The state standard of the union cf.
STATE STANDARD OF THE UNION OF THE SSR
RELIABILITY IN TECHNOLOGY
COMPOSITION AND GENERAL RULES OF THE TASK
RELIABILITY REQUIREMENTS
GOST 27.003-90
USSR STATE MANAGEMENT COMMITTEE
PRODUCT QUALITY AND STANDARDS
Moscow
STATE STANDARD OF THE UNION OF THE SSR
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Reliability in engineering COMPOSITION AND GENERAL RULES OF THE TASK Industrial product dependability. Dependability |
GOST |
Introduction date 01.01.92
This standard applies to all types of products and establishes the composition, procedure and general rules for setting reliability requirements for their inclusion in the regulatory and technical (NTD) and design documentation. The standard is mandatory for products developed by order of the Ministry of Defense, and recommended for other products. The requirements of this standard can be specified in the NTD by type of equipment. The terms used in this standard and their definitions are in accordance with GOST 27.002.
1. GENERAL PROVISIONS
1.1. Reliability requirements - a set of quantitative and (or) qualitative requirements for reliability, durability, maintainability, shelf life, the fulfillment of which ensures the operation of products with specified indicators of efficiency, safety, environmental friendliness, survivability and other quality components that depend on the reliability of the product, or the possibility of using this product as an integral part of another product with a given level of reliability. 1.2. When setting reliability requirements, the following are determined (selected) and agreed between the customer (consumer) and the product developer (manufacturer): a typical operating model (or several models), in relation to which (which) the reliability requirements are set; failure criteria for each operation model, for which reliability requirements are set; criteria for limit states of products, for which requirements for durability and shelf life are established; the concept of "output effect" for products, the reliability requirements for which are established using the "efficiency retention factor" indicator K ef; nomenclature and values of reliability indicators (RI), in relation to each operation model; methods for monitoring the compliance of products with specified requirements for reliability (reliability control); requirements and (or) restrictions on design, technological and operational methods of ensuring reliability, if necessary, taking into account economic restrictions; the need to develop a program to ensure reliability. 1.3. A typical product operation model should contain: a sequence (cyclogram) of stages (types, modes) of operation (storage, transportation, deployment, waiting for intended use, intended use, maintenance and scheduled repairs) indicating their duration. characteristics of the adopted system of maintenance and repair, provision of spare parts, tools and operating materials; levels of external influencing factors and loads for each stage (type, mode) of operation; the number and qualifications of maintenance and repair personnel. 1.4. The nomenclature of the specified PN of the product is selected in accordance with the provisions of this standard and agreed in the prescribed manner between the customer (consumer) and the developer (manufacturer). Indicators, as a rule, should be selected from among the indicators, the definitions of which are given in GOST 27.002. It is allowed to use indicators whose names and definitions specify the relevant terms established by GOST 27.002, taking into account the characteristics of the product and (or) the specifics of its use, but do not contradict the standardized terms. Symbols of indicators used in this standard are given in Appendix 1, examples of possible modifications of standardized indicators - in Appendix 2. 1.5. The total number of indicators assigned to the product should be minimal, but characterize all stages of its operation. All indicators must have an unambiguous interpretation, and for each of them there must be methods of control (evaluation) at all stages of the life cycle of products. 1.6. For products that are subject to storage (transportation) before or during operation, shelf life indicators are set. At the same time, the conditions and modes of storage (transportation) should be determined and taken into account, in relation to which the indicated indicators are set. 1.7. For remanufactured products, as a rule, a complex PN or a set of individual indicators of reliability and maintainability that defines it is set, and the first option for setting requirements is preferable. At the request of the customer, in addition to the complex indicator, one of the indicators of reliability or maintainability that determines it can be set. It is not allowed to simultaneously set the complex and all single indicators that define it. For maintainability indicators, the conditions and types of restoration, repair and maintenance should be determined and taken into account, in relation to which these indicators are set. Example. For renewable products of continuous action, the output effect from the use of which is proportional to the total duration of the stay of products in working condition, the main indicator is To d. By agreement between the customer and the developer, the following combinations of specified indicators are possible: To d and T about or To d and T in, or T oh and T a . Invalid combination: To G, T oh and T in . 1.8. With a statistical method of control, to select a plan for monitoring the compliance of products with specified reliability requirements for each PN, the necessary initial data are established: acceptance R a and reject R b , levels, risks of customer (consumer) b and supplier (manufacturer) a or confidence probability g and the value of the ratio of the upper R in and bottom R n confidence boundaries. 1.9. Requirements for constructive methods of ensuring reliability may include: requirements and (or) restrictions on the types and multiplicity of redundancy; requirements and (or) restrictions on costs (cost) in the manufacture and operation, weight, dimensions, volume of the product and (or) its individual components, spare parts kits, equipment for maintenance and repairs; requirements for the structure and composition of spare parts and accessories; requirements for the system of technical diagnostics (technical condition monitoring); requirements and (or) restrictions on methods and means of ensuring maintainability and storability; restrictions on the range of components and materials permitted for use; requirements for the use of standardized or unified components, etc. 1.10. Requirements for technological (production) methods of ensuring reliability may include: requirements for the accuracy parameters of technological equipment and its certification; requirements for the stability of technological processes, the properties of raw materials, materials, components; requirements for the need, duration and modes of technological run (running, electric thermal training, etc.) of products in the manufacturing process; requirements for methods and means of monitoring the level of reliability (defectiveness) during production, etc. 1.1. Requirements for operational methods of ensuring reliability may include: requirements for the system of maintenance and repairs; requirements for the algorithm of technical diagnostics (technical condition monitoring); requirements for the number, qualifications, duration of training (training) of maintenance and repair personnel; requirements for methods for eliminating failures and damages, the procedure for using spare parts and accessories, rules for adjustments, etc.; requirements for the volume and form of presentation of information on reliability collected (recorded) during operation. etc. 1.12. Reliability requirements include: tactical and technical specifications (TTZ), technical specifications (TOR) for the development or modernization of products; technical specifications (TS) for the manufacture of experimental and serial products (if the rules or conditions for their confirmation are agreed); standards of general technical requirements (OTT), general technical specifications (OTU) and technical specifications (TU). In passports, forms, instructions and other operational documentation, reliability requirements (reliability indicators) are indicated by agreement between the customer (consumer) and the developer (manufacturer) as a reference. Reliability requirements can be included in contracts for the development and supply of products.2. PROCEDURE FOR SETTING REQUIREMENTS FOR RELIABILITY AT DIFFERENT STAGES OF THE LIFE CYCLE OF PRODUCTS
2.1. The reliability requirements included in the technical specification (TOR) are initially determined at the stage of research and development justification by performing the following work: analysis of the requirements of the customer (consumer), purpose and operating conditions of the product (or its analogues), restrictions on all types of costs, including including design, manufacturing technology and operating costs; development and coordination with the customer (consumer) of failure criteria and limit states; selection of a rational nomenclature of specified PN; establishing the values (norms) of the PN of the product and its components. 2.2. At the product development stage, as agreed between the customer (consumer) and the developer, it is allowed to clarify (adjust) the reliability requirements with an appropriate feasibility study by performing the following work: considering possible schematic and design options for constructing the product and calculating the expected level of reliability for each of them, as well as indicators characterizing the types of costs, including operating costs, and the possibility of fulfilling other specified restrictions; selection of a schematic and constructive variant of constructing a product that satisfies the customer in terms of the totality of PV and costs; clarification of the values of the PN of the product and its components. 2.3. When forming specifications for serial products, it includes, as a rule, those PNs from those specified in the technical specifications (TOR) that are supposed to be controlled at the stage of manufacturing the product. 2.4. At the stages of serial production and operation, it is allowed, by agreement between the customer and the developer (manufacturer), to correct the values of individual PVs based on the results of tests or controlled operation. 2.5. For complex products during their development, pilot and mass production, it is allowed to set step-by-step values of PV (subject to increased reliability requirements) and parameters of control plans, based on established practice, taking into account the accumulated statistical data on previous analog products, and as agreed between the customer (consumer) and developer (manufacturer). 2.6. In the presence of prototypes (analogues) with a reliably known level of reliability, the scope of work for setting reliability requirements, given in paragraphs. 2.1 and 2.2, can be reduced due to those indicators, information on which is available at the time of the formation of the TTZ (TR) section, TS "Reliability Requirements".3. SELECTION OF THE NOMENCLATURE OF SET PN
3.1. The choice of the nomenclature of PN is carried out on the basis of the classification of products according to the characteristics characterizing their purpose, the consequences of failures and the achievement of the limit state, the features of application modes, etc. 3.2. The determination of the classification features of products is carried out by engineering analysis and the coordination of its results between the customer and the developer. The main source of information for such an analysis is the TTZ (TK) for the development of a product in terms of the characteristics of its purpose and operating conditions, and data on the reliability of analog products. 3.3. The main features by which products are subdivided when setting reliability requirements are: certainty of the purpose of the product; the number of possible (taken into account) states of products in terms of operability during operation; mode of application (functioning); possible consequences of failures and (or) reaching the limit state during application and (or) consequences of failures during storage and transportation; the ability to restore a healthy state after a failure; the nature of the main processes that determine the transition of the product to the limit state; the possibility and method of restoring a technical resource (service life); possibility and necessity of maintenance; the possibility and necessity of control before use; the presence of computer equipment in the composition of products. 3.3.1. According to the certainty of the purpose, the products are divided into: products for a specific purpose (IKN), which have one main option for their intended use; endowing with general purpose (ION), having several applications. 3.3.2. According to the number of possible (taken into account) states (according to operability), products are divided into: type I products, which during operation can be in two states - operable or inoperable; products of type II, which, in addition to the two states indicated, may be in a certain number of partially inoperable states, into which they pass as a result of a partial failure. Note e. To simplify the procedure for setting (and subsequent control), by agreement between the customer and the developer, it is allowed to lead products of type II to products of type I by conditionally dividing the set of partially inoperative states into two subsets of states, one of which is classified as operational, and the other - to inoperable state. To divide the set of states into two subsets, a general rule is recommended: if in a partially inoperable state it is advisable to continue to use the products for their intended purpose, then this state is classified as operable, otherwise it is inoperable. It is also allowed to disaggregate products of type II into component parts of type I and establish reliability requirements for the product as a whole in the form of a set of PN of its component parts. For products that have a channel principle of construction (communication systems, information processing, etc.), the requirements for reliability and maintainability can be set in the calculation of one channel or for each channel with channels that are unequal in efficiency. 3.3.3. According to the modes of application (functioning), products are divided into: products of continuous long-term use; products of multiple cyclic use; single-use products (with a previous waiting period for use and storage). 3.3.4. According to the consequences of failures or reaching the limit state during use, or the consequences of failures during storage and transportation, products are divided into: products, failures or transition to the limit state of which lead to consequences of a catastrophic (critical) nature (to a threat to human life and health, significant economic losses etc.); products whose failures or transition to the limit state do not lead to consequences of a catastrophic (critical) nature (without a threat to human life and health, insignificant or "moderate" economic losses, etc.). 3.3.5. If it is possible to restore a working state after a failure during operation, the products are divided into: recoverable; non-recoverable. 3.3.6. According to the nature of the main processes that determine the transition to the limit state, products are divided into: aging; wearable; aging and worn out at the same time. 3.3.7. According to the possibility and method of restoring the technical resource (service life) by carrying out scheduled repairs (medium, capital, etc.), products are divided into: non-repairable; repaired in an anonymous way; repaired in a non-depersonalized way.Table 1
Generalized scheme for choosing the nomenclature of specified PN
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Product Feature |
Nomenclature of set PN |
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| Efficiency retention ratio K ef or its modifications (examples of possible modifications K eff are given in Appendix 2); indicators of durability, if the concept of "limiting state" can be unambiguously formulated for the product and criteria for its achievement are defined; shelf life indicators, if the product provides for storage (transportation) in its entirety and assembled form, or shelf life indicators of separately stored (transported) parts of the product | |||
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Recoverable |
Integrated duty cycle and, if necessary, one of the reliability or maintainability indicators that determine it (in accordance with clause 1.7); indicators of durability and storage, selected similarly to products of type I I | ||
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Unrecoverable |
Single indicator of failure-free operation; indicators of durability and storage, selected similarly to products of type II | ||
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Recoverable and non-recoverable |
A set of PN components of the product, considered poppy products of type I | ||
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Recoverable |
Integrated duty cycle and, if necessary, one of the reliability or maintainability indicators that determine it (in accordance with clause 1.7); indicators of durability and storage, selected similarly to ICH type I | ||
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Unrecoverable |
Single indicator of failure-free operation; indicators of durability and storage, selected similarly to ICH type I | ||
4. CHOICE AND JUSTIFICATION OF THE VALUES OF ST
4.1. Values (norms) of PN of products are set in TTZ (TK), TS, taking into account the purpose of products, the level achieved and the identified trends in improving their reliability, a feasibility study, the capabilities of manufacturers, the requirements and capabilities of the customer (consumers), the initial data of the selected control plan. When applying product control plans with specified acceptance R a and rejection R b levels design at the development stage is carried out in such a way that at the production stage the actual level of PV corresponding to the level of R a . Level value R a represents, at the development stage, the design norm of the ST. 4.2. The calculated (estimated) values of the ST of the product and its components, obtained after the completion of the next stage (stage) of work, are taken as reliability standards in force at the next stage (stage), after which these standards are specified (corrected), etc. 4.3. Calculation, experimental or calculation-experimental methods are used to substantiate the values of ST. 4.4. Calculation methods are used for products for which there are no statistical data obtained during testing of analogues (prototypes). 4.5. Experimental methods are used for products for which it is possible to obtain statistical data during testing or having analogues (prototypes), (allowing to evaluate their ST, as well as trends in changing ST from one analogue to another. Such estimates of ST are used instead of the calculated values of ST of the product and ( or) its component parts.4.6 Computational-experimental methods are a combination of computational and experimental methods.They are used in cases where statistical data on reliability are available for individual components, and calculation results for others, or when preliminary test results of products, 4.7. For the stage-by-stage setting of reliability requirements, calculation and experimental methods are used based on models of reliability growth in the process of testing products and mastering them in production. Growth models are determined by statistical data obtained during the creation and (or) operation analogue products. 4.8. Guidelines for justifying the values of the specified indicators are given in Appendix 5.5. RULES FOR ESTABLISHING FAILURE CRITERIA AND LIMIT STATES
5.1. Categories of failures and limit states are established in order to unambiguously understand the technical condition of products when setting requirements for reliability, testing and operation. The definitions of failure criteria and limit states should be clear, specific, and not subject to ambiguous interpretation. Criteria for limit states should contain indications of the consequences that occur after their discovery (sending products for repair of a certain type or write-off). 5.2. The criteria for failures and limit states should ensure the ease of detecting the fact of a failure or transition to a limit state visually or using the provided means of technical diagnostics (technical condition monitoring). 5.3. Criteria for failures and limit states should be established in the documentation in which the values of ST are given. 5.4. Examples of typical failure criteria and limit states of products are given in Appendix 6, and examples of the construction and presentation of sections "Requirements for reliability" in various RTDs are in Appendix 7.APPENDIX 1
Reference
SYMBOLS USED IN THIS STANDARD
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K i.e. |
Technical utilization factor; |
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Availability factor; |
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K o.g |
Operational readiness factor; |
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K t.i.ozh |
- K i.e. standby application; |
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K city of |
- To d standby application; |
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Efficiency retention ratio; |
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R(t b.r) |
Probability of no-failure operation during running time t b.r; |
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t b.r. |
Operating time, within which the probability of failure-free operation of the product is not lower than the specified one; |
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R(t in) |
Probability of recovery (for a given time t in) ; |
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Waiting time for intended use; |
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Average recovery time; |
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T c.ozh |
Average recovery time in standby mode; |
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R 0(on) |
Probability of failure-free operation (switching on); |
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T about |
Mean time to failure (time to failure); |
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Mean time to failure; |
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Failure rate; |
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T r.av.sp |
Average resource before write-off (full); |
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T r.sr.c.r |
Average resource before major (medium, etc.) repair; |
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T sl.med.sp |
Average service life before decommissioning (full); |
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T sl.sr.c.r |
Average service life before overhaul (medium, etc.) repair; |
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T p g cn |
Gamma-percentage resource before write-off (full); |
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T r g k.r |
Gamma-percentage resource before major (medium, etc.) repair; |
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T sl g cn |
Gamma Percentage Life to Retirement (Full); |
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T sl g to r |
Gamma-percentage service life before overhaul (medium, etc.) repair; |
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T c. cf |
Average shelf life; |
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- gamma percentage shelf life; |
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P(t xp) |
Probability of trouble-free storage; |
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Shelf life; |
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R (l tr) |
Probability of trouble-free transportation; |
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Transportation distance; |
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Acceptance level PN; |
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R b |
Rejection level PN; |
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Supplier's (manufacturer's) risk; |
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Risk of the consumer (customer); |
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Confidence probability; |
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Upper confidence limit of ST; |
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R n |
Lower confidence limit of PN. |
APPENDIX 2
Reference
EXAMPLES OF POSSIBLE MODIFICATIONS AND DEFINITIONS OF STANDARDIZED INDICATORS
1. The definitions of PN in GOST 27.002 are formulated in general terms, without taking into account the possible specifics of the purpose, application, design of products and other factors. When setting PN for many types of products, there is a need to specify their definitions and names, taking into account: the definition of the concept of "output effect" for products, the main indicator of which is the "efficiency retention coefficient" K eff; stage of operation, in relation to which the PN is set; the classification of failures and limit states adopted for the products under consideration.2. K eff according to GOST 27.002 is a generalized name for a group of indicators used in various branches of technology and having their own names, designations and definitions. Examples of such indicators can be: for technological systems: "productivity retention coefficient"; shift (month, quarter, year)", etc.; for space technology: "probability of completing the flight program" by the spacecraft, etc.; for aviation technology: "probability of performing a typical task (flight task) in a given time" aircraft, etc. At the same time, the words "productivity", "product", "product quality", "flight program", "typical task", "flight task", etc., characterizing the "output effect " products.3. For some products, the PN should be set in relation to the individual stages of their operation (application). So, for example, for aviation technology, the following varieties of the indicator "mean time between failures" are used: "mean time between failures in flight"; "mean time between failures during preflight preparation", etc.; for rocket technology: "probability of failure-free preparation to the launch and failure-free launch of the missile"; "probability of failure-free flight of the missile"; "probability of failure-free operation at the target".4. For many critical products, the PN is set separately for critical and other failures. For example, for aviation equipment, in addition to the "mean time between failures", "mean time between failures leading to a departure delay" is set, etc. " and "mean time between failures of a faulty nature (per failure)".APPENDIX 3
METHODOLOGY FOR SELECTING THE NOMENCLATURE OF ASSIGNED ST
1. The general principle of choosing a rational (minimum necessary and sufficient) nomenclature of specified PNs is that in each specific case the product is classified sequentially according to established features that characterize its purpose, features of the circuit design and specified (assumed) operating conditions. Depending on the totality of the classification groupings to which it is assigned, a set of indicators to be set is determined using work tables.2. The procedure for selecting the nomenclature of specified duty cycles for new (developed or modernized) products consists of three independent stages: selection of reliability and maintainability and (or) complex indicators; selection of durability indicators; selection of persistence indicators.3. The nomenclature of reliability, maintainability and (or) complex indicators is established for products of type I in accordance with Table. 2, and for products of type II - table. 3.4. It is advisable to set the reliability indicators taking into account the criticality of failures. At the same time, criteria for each type of failure should be formulated in TTZ (TK), TS.5. For products that include discrete technology devices (computers), reliability, maintainability and complex indicators should be set taking into account failures of a faulty nature (failures). In this case, the given indicators are explained by adding the words "taking into account failures of a faulty nature" or "without taking into account failures of a faulty nature". In the case of a phased specification of requirements, it is allowed not to take into account failures at early stages. Appropriate criteria should be formulated for failures of a faulty nature.6. For products controlled before use for their intended purpose, it is allowed to additionally set the average (gamma-percentage) time for bringing the product to readiness or the average (gamma-percentage) duration of readiness control.7. For serviced products, it is additionally allowed to establish indicators of the quality of maintenance.8. The choice of indicators of durability of IKN and ION is carried out in accordance with table. 4. For the purpose of simplification in table. 4 shows the most common type of scheduled repairs - major. If necessary, similar durability indicators can be set relative to "medium", "basic", "dock" and other scheduled repairs.9. The choice of indicators of preservation of IKN and ION is carried out in accordance with table. 5.10. For products whose transition to the limit state or failure of which during storage and (or) transportation can lead to catastrophic consequences, and the control of the technical condition is difficult or impossible, instead of the gamma percentage indicators of durability and shelf life, the assigned resource, service life and shelf life should be set. . At the same time, in the TTZ (TR), TS indicate what part (for example, not more than 0.9) the assigned resource (service life, shelf life) should be from the corresponding gamma percentage indicator with a sufficiently high confidence probability g (for example, not less than 0.98 ).table 2
Selection of the nomenclature of reliability and maintainability indicators or complex indicators for products of type I
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Classification of products according to the characteristics that determine the choice of PN |
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By appointment |
According to the mode of application (functioning) |
Possible restoration and maintenance |
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Recoverable |
Non-recoverable |
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serviced |
Unattended |
Serviced and non-serviced |
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| Products of continuous long-term use (NPDP) |
K g** or K i.e. ; T about ; T in * |
K G ; T about ; T in * |
R( t b.r)** or T Wed |
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| Products of repeated cyclic use (MCRP) |
K o .g ( t b.r) = To G × P (t b.r); T in |
R on ( R 0) and T Wed T Wed |
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| Single use devices (preceded by a waiting period) (SER) |
K t.i.ozh; P (t b.r); T in, oh * |
K city of ; P (t b.r); T in, oh * |
P (t oh); P (t b.r); |
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| Products NPDP and MKCP |
K t.i; T o ; T in * |
K G ; T about ; T in * |
T g ** or T Wed |
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| OKRP products |
R on ( R 0) |
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Table 3
Selection of nomenclature of reliability and maintainability indicators or complex indicators for products of type II
* Set in addition to K ef in the presence of restrictions on the duration of recovery. If necessary, taking into account the specifics of the products, instead of T c one of the maintainability indicators can be set: gamma-percentage recovery time N in g; likelihood of recovery R(t c) or the average complexity of restoration G in. ** Set for products that perform critical functions; otherwise, the second indicator is set.Table 4
Selection of the nomenclature of durability indicators
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Classification of products according to the characteristics that determine the choice of indicators |
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Possible consequences of transition to the limit state |
The main process that determines the transition to the limit state |
Possibility and method of restoring a technical resource (service life) |
||
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Non-repairable |
Repaired in an anonymous way |
Repaired in a non-depersonalized way |
||
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Products whose transition to the limit state when used as intended can lead to catastrophic consequences (technical condition monitoring is possible) |
Wear |
T R. g cn |
T r g k.r |
T p g cn; T r g k.r |
|
Aging |
T sl g cn |
T sl g k.r |
T sl g cn; T sl g k.r |
|
|
T p g cn; T sl g cn |
T p g k.r; T sl g k.r |
T p g cn; T p g k.r; 7 T sl g cn; T sl g k.r |
||
|
Products whose transition to the limit state when used as intended does not lead to catastrophic consequences |
Wear |
T R. cf. cn |
T R. cf. k.r. |
T R. cf. cn; T R. cf. k.r. |
|
Aging |
T sl.. cf. cn |
T sl. cf. k.r. |
T sl.. cf. cn; T sl. cf. k.r. |
|
|
Wear and tear at the same time |
T R. cf. cn; T sl.. cf. cn |
T R. cf. k.r; T sl. cf. k.r. |
T R. cf. cn; T R. cf. k.r; T sl.. cf. cn; T sl. cf. k.r. |
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Table 5
Choice of nomenclature of preservation indicators
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A feature that determines the choice of preservation indicators |
Set indicator |
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Possible consequences of reaching the limit state or failure during storage and (or) transportation |
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| Products, the achievement of the limiting state of which or the failure of which during storage and (or) transportation can lead to catastrophic consequences (technical condition monitoring is possible) |
T with g |
| Products, the achievement of the limiting state of which or the failures of which during storage and (or) transportation do not lead to catastrophic consequences |
T s.sr. |
APPENDIX 4
Reference
EXAMPLES OF SELECTING THE NOMENCLATURE OF SET INDICATORS
Example 1. Portable radio stationRadio station - ICH type I, multiple cyclic use, recoverable, serviceable. Set indicators according to table 2:K o.g = K g×p( t b. p); T in.
A radio station is a product whose transition to the limit state does not lead to catastrophic consequences, aging and wearing out at the same time, repaired in an impersonal way, and stored for a long time. Specified indicators of durability and storability according to the table. 4 and 5: T r.sr.c.r; T sl.sr.r.r., T c.sr. Example 2. Universal electronic computer (computer) COMPUTER - ION type I, continuous long-term use, recoverable, serviceable, the transition to the limit state does not lead to catastrophic consequences, aging, non-repairable, not stored for a long time. Specified indicators according to the table. 2 and 4: K t.i; T about (or T in the presence of restrictions on the duration of recovery after failure); T Example 3. Transistor A transistor is an ION of type I (a highly reliable component for interindustry use), continuous long-term use, non-recoverable, maintenance-free, the transition to the limit state does not lead to catastrophic consequences, wearing out, aging during storage. Specified indicators according to the table. 2, 4 and 5: l,; T r.sr.sp; T s.sr.
annex 5
Reference
METHODOLOGICAL INSTRUCTIONS ON THE SUBSTANTIATION OF THE VALUES (NORMS) OF THE SET PN
1. General Provisions
1.1. The methodological approach to substantiating the PN norms for ICH and ION is different. 1.2. The methodology for substantiating the PN norms does not depend on the type of indicator, therefore the PN is denoted by one common symbol R. 1.3. The technique is applied in those cases when the following are known or can be established: a) possible options for constructing a product and a set of measures to improve reliability relative to the initial "base" level; b) values of the increase in reliability (D R i) and costs (D Withi) for each of these options (measures); c) the type of dependence "efficiency - reliability" - E=E(R) , the knowledge of which is necessary additionally, along with "a" and "b" when solving the problem, when the output effect and the cost of ensuring reliability are the values of the same type (see clause 2.2.2.1). options for constructing a product turn out to be different, then the final decision is made on the basis of a comparative analysis of such options, taking into account the level of designation indicators, weight and size, technical, economic and other quality characteristics. product and the distribution of PN norms between its component parts.
2. Determination of norms of PN (R tr) for new developments of ICH
2.1. Statement of the problem and initial data2.1.1. The level of reliability of the product must not be lower than a certain minimum R min , at which the creation (use) of the product still makes sense, taking into account the limiting factors. R min - can be a number or range.2.1.2. If there are several limiting factors, then one of them is chosen, based on the condition that the restriction on it in the process of increasing reliability occurs earlier than others. Next, one limiting factor is considered, which is taken as the most common - the cost C og p .2.1.3. In general, the efficiency dependence E(R) and cost C(R) product from the level of its reliability has the form presented in Fig. one.
The nature of dependenciesE(R) , C (R) andDE (R) = E(R)- C (R) (when E and With values of one kind)
2.1.4. Under these conditions, the problem can be formulated as follows: it is necessary to determine the level of reliability of the product, as close as possible to the optimal, satisfying the constraints R ³ sR min ; C (R) £ C og p . 2.2. Solution of problem 2.2.1. The general procedure for solving the problem is as follows. The level of reliability of the original version of the product is assessed, the reasons for its insufficient reliability are studied, and possible measures to improve reliability and various options for constructing products are considered. For each event (option), the costs D Withi to increase the level of reliability, a possible increase in D R i reliability indicators, build the optimal dependence C (R) or R(C) and determine the increase in efficiency D Ei. Of all the activities, choose the most effective one according to D Ei or D Ei/D Withi, and then the calculation is repeated with a new initial variant (with a reliability level R reached after the next event). A generalized scheme for solving the problem is shown in Fig. 2.2.2.2. Particular cases of the solution, which differ in the ratio of the output effect of the product and the cost of ensuring the required reliability, are given below. 2.2.2.1. The output effect and the cost of ensuring reliability are values of the same type (measured in the same units; most often it is the economic effect and cash costs), and the damage from failures is insignificant or commensurate with the cost of the product. In this case, they constitute the target function DE (R) , which is the difference or ratio of the functions E(R) and C (R). If it is important to ensure the maximum absolute value of the effect, then calculate the difference DE (R)= E (R)- C (R) , which has the maximum R(Fig. 1). If it is important to get the maximum effect per unit of funds spent (relative effect), then the ratio is calculated K n = E(R)/C (R). After the optimum is found, it is necessary to check the fulfillment of the cost constraint. If it fails [ With (R opt)>С ogr], it is expedient to set the maximum reliability R (C ogr), achievable under the given constraint, and check the fulfillment of the constraint [ R (C ogre) ³ R min]. If it is not met, then the problem cannot be solved, and a revision of the initial data, constraints, etc. is necessary. If the cost constraint is met [ With(R wholesale) £ C og p], then check the condition R wholesale ³ R min . When executed, it is set R wholesale, in case of failure - R min , with constraint check With (R min) £ C limited 2.2.2.2. The output effect and the cost of ensuring reliability are of the same type, but the damage from failures is large (incommensurable with the cost of the product) due to the loss of high efficiency or due to catastrophic consequences. This is possible for two reasons: either a serviceable product has a very high effect and it decreases sharply in case of failures, or failures cause such great harm that the effect reaches negative values. In this case R opt is shifted to the right and the problem is solved starting from the definition R(With ogr) according to the constructed optimal dependence R(C). Then (as in the case according to clause 2.2.2.1) the condition is checked R(With ogr) ³ R min. If the test result is positive, set R(With ogr), if negative - the problem is not solved. 2.2.2.3. The output effect of the product and the costs of ensuring reliability are quantities of various types; product failures lead to large losses (as in clause 2.2.2.2). The problem here is solved in the same way as in clause 2.2.2.2 - one should strive to increase reliability until the customer's capabilities are exhausted. 2.2 .2.4. The output effect of the product and the costs of ensuring reliability are values of different types, but product failures do not lead to losses significantly greater than the costs of the product. In this case, determine R min and check the condition: R min³ R(With ogre). If it is satisfied, then set the level R ex ranging from R min up to R(With ogr) based on the results of engineering analysis (since the effect and costs are not comparable), if not performed, the task is not solved (i.e., it is necessary to return to the revision of the initial data). 2.2.3. The algorithm for solving the problem is shown in Fig. 2. In this case, the operations of the algorithm can be performed with different accuracy. For example, to compare R(With ogre) with R min is optional to set the exact value R min , it is enough to analyze the influence R(With ogr) on the level of product efficiency. If this level is acceptable, then R(With ogr) ³ R min and vice versa. The cost constraint can be formulated not only as a specific value With ogr, but also in the form of consequences to which certain costs lead. Then you can specify the cost ranges that are considered acceptable and unacceptable. In this case, comparison, for example, With wholesale and With ogr is carried out by analysis With wholesale, and if it is recognized as acceptable, then we can consider With wholesale ³ With limit 2.3. Construction of the optimal function "reliability-cost" 2.3.1. Building a Function C (R) or R (C) is necessary to determine the optimal or maximum level of reliability achievable under a given constraint.2.3.2. Addiction R (C) used to justify the requirements should be optimal in the sense that each of its points should correspond to the highest reliability for a given cost and the lowest cost for a given reliability. The solution of this problem is carried out by enumeration of possible options for constructing the product. If each product variant is shown on the graph as a point with coordinates R and With, then they all form a certain set (Fig. 3). The line enveloping the set from the left and from above passes through the most reliable options corresponding to a certain cost. This line is a function R (With) or C (R). The remaining options are obviously worse and their consideration is inappropriate (in this case, it is assumed that all options have "equivalent" other parameters, in particular, destination parameters).
Generalized Reliability Level Selection Scheme
2.3.3. For the case when the increase in reliability is achieved by redundancy, the following method of enumeration of options for building a product is recommended: a) determine the "zero" option for building a product in which there is no reserve; b) consider options, in each of which one backup device of the same type is introduced, for each of these options calculate the increments of the product reliability index DR and its cost D With;c) choose the option with the maximum ratio D R/D With; (the reserve adopted in this option is not revised further); d) options are considered, in each of which one more device of each type is introduced, including the already selected option with an added reserve. Then the procedure is repeated for positions "c" and "d ". In this case, the sequence of selected options forms the desired curve - the envelope of the set, i.e., the optimal dependence of reliability on cost.
Optimum Reliability-Cost Function
2.3.4. In the general case, they consider increasing the reliability of the product not only through redundancy, but also through any other measures. If the components of the product are quite complex products, then for each of them various options for improving reliability are also possible. Then the procedure is carried out in two stages: for each of the constituent parts, a particular optimal function is built R (C) and the corresponding sequence of options for constructing this component; construct the optimal function R (C) for the product as a whole, while at each step of the procedure, an increase in the reliability of the product is considered due to the transition of each component to the next point of its particular optimal function R (C), m, i.e., to the next version of the construction.
3. Definition of norms of PN R tr for new ION developments
3.1. The fundamental difference between general-purpose products is the variety of their application, which makes it impossible to analyze the impact of reliability on the result of the work.3.2. If it is possible to indicate characteristic areas of application for the ION or such an application that makes the highest demands, then it should be considered as an IQN, and the problem is reduced to the previous one. If this fails, then the requirements can be assigned based on peer data. In this case, the following actions are performed: they build the optimal sequence of product options (it is also the optimal dependence R (C), as indicated in paragraph 2.3); check the fulfillment of the condition R(With ogr) ³ R analogue. If the condition is met, i.e., the restrictions make it possible to make a new product no worse than the best existing analogues, then, according to the results of engineering analysis, the value R the ex must be in the range R min -R(With ogre) . If the conditions are not met, then the problem in the considered version is not solved.
APPENDIX 6
Reference
EXAMPLES OF TYPICAL FAILURE CRITERIA AND LIMIT STATES
1. Typical failure criteria can be: the termination of the performance of the specified functions by the product; decrease in the quality of functioning (performance, power, accuracy, sensitivity and other parameters) beyond the permissible level; distortion of information (wrong decisions) at the output of products that have and we will sing as part of a computer or other devices of discrete technology, due to failures (failures of a faulty nature) ; external manifestations indicating the onset or prerequisites for the onset of an inoperable state (noise, knocking in the mechanical parts of products, vibration, overheating, release of chemicals, etc.).2. Typical criteria for the limit states of products can be: failure of one or more components, the restoration or replacement of which at the place of operation is not provided for by the operational documentation (should be carried out in repair bodies); mechanical wear of critical parts (assemblies) or a decrease in the physical, chemical, electrical properties of materials to the maximum permissible level; decrease in the time between failures (increased failure rate) of products below (above) the permissible level; exceeding the established level of current (total) maintenance and repair costs or other signs that determine the economic inexpediency of further operation.APPENDIX 7
Reference
EXAMPLES OF CONSTRUCTION AND STATEMENT OF SECTIONS "RELIABILITY REQUIREMENTS" IN TTZ (TR), TS, STANDARDS OF TYPES OF OTT (OTU) AND TU
1. Reliability requirements are drawn up in the form of a section (subsection) with the heading "Reliability requirements".2. In the first paragraph of the section, the nomenclature and values of PN are given, which are recorded in the following sequence: complex indicators and (or) single indicators of reliability and maintainability; indicators of durability; indicators of persistence. Recommended wording: "Reliability
in the conditions and modes of operation, the name of the product established by paragraphs _________ of this TTZ (TK), TS, must be characterized by the following values of PN ... (these indicators are given below). Example. Reliability of channel-forming telegraph equipment under the conditions and modes of operation established by paragraphs. _________, should be characterized by the following values of indicators: mean time between failures - at least 5000 hours; average recovery time at the operation site by forces and means of the shift on duty - no more than 0.25 hours; full average service life - at least 20 years; average shelf life in the original packaging in a heated room - at least 6 years.2.1. In OTT standards, reliability requirements are given in the form of maximum allowable PN values for products of this group.2.2. In the standards of the OTU (TU) types and in the TS, the reliability requirements are set in the form of the maximum permissible values of those indicators that are controlled during the manufacture of a product of this group, and are given as reference values of the indicators specified in the TOR for the development of the product, but in the manufacturing process it is not controlled.3. In the second paragraph, definitions (criteria) of failures and limit state are given, as well as the concepts of "output effect" or "product efficiency", if the efficiency retention factor is set as the main PN K ef). Recommended formulations: Limit state 
consider ... Refusal 
consider ... The output effect is estimated at ... Efficiency 
equal to ... Example 1. The limiting state of a car is considered to be: deformation or damage to the frame that cannot be eliminated in operating organizations; the need to simultaneously replace two or more main units; excess of the annual total cost of maintenance and current repairs by ... rub. Example 2. Car failure consider: engine crankshaft jamming; engine power reduction below ...; engine smoke at medium and high speeds; tire pressure drop, tire puncture, etc. Example 3. The output effect of a mobile diesel power plant is estimated by generating a given amount of electricity for a given time with established quality parameters.4. The third paragraph provides general requirements for reliability assessment methods and initial data for assessing the compliance of products with the reliability requirements of each of the methods. Recommended wording: "Compliance 
reliability requirements set out in paragraphs. ..., at the design stage, they are evaluated by the calculation method using data on the reliability of components according to 
; at the stage of preliminary tests - by the calculation and experimental method according to 
, taking values of confidence probability not less than. ...; at the stage of mass production by control tests according to 
, using the following inputs for test planning: rejection rate R b (indicate values); customer risk B (indicate values); acceptance level R a (indicate values); supplier risk a (indicate values). In some cases, it was allowed to use other initial data in accordance with the current NTD.5. In the fourth paragraph of the section, if necessary, requirements and restrictions are given on ways to ensure the specified values of PN (in accordance with paragraphs 1.9-1.11 of this standard). INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the USSR State Committee for Product Quality Management and StandardsDEVELOPERSBUT. Demidovich, cand. tech. sciences (topic leader); L.G. Smolyanitskaya; AND I. Rezinovsky, cand. tech. sciences; A.L. Ruskin; M.V. Zhurtsev, cand. tech. sciences; E.V. Dzirkal, Candidate of Engineering sciences; V.V. Yukhnevich; A.K. Petrov; T.V. Nevezhina; V.P. Chagan; N.G. Moiseev; G.I. Lebedev; N.S. Fedulova 2 APPROVED AND INTRODUCED BY Decree of the USSR State Committee for Product Quality Management and Standards dated December 29, 1990 No. 3552 3. DATE OF VERIFICATION - 19964. REPLACE RD 50-650-87 5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS|
1. Basic provisions. one 2. The procedure for setting requirements for reliability at various stages of the life cycle of products. 3 3. Choice of the nomenclature of the given mon.. 4 4. Selection and justification of the values of mon.. 6 5. Rules for establishing failure criteria and limit states. 6 Appendix 1 Conventions used in this standard. 7 Annex 2 Examples of possible modifications and definitions of standardized indicators. 7 Appendix 3 The methodology for choosing the nomenclature of the given mon.. 8 Appendix 4 Examples of choosing the nomenclature of specified indicators. ten Annex 5 Guidelines for substantiating the values (norms) of the given mon.. 11 Appendix 6 Examples of typical failure criteria and limit states. fifteen Annex 7 Examples of the construction and presentation of the sections "requirements for reliability" in ttz (tz), tu, standards of types ott (otu) and tu .. 15 |
GOST 27.301-95
Group T51
INTERSTATE STANDARD
RELIABILITY IN TECHNOLOGY
RELIABILITY CALCULATION
Key points
Dependability in technics.
Dependability prediction. basic principles
ISS 21.020
OKSTU 0027
Introduction date 1997-01-01
Foreword
1 DEVELOPED MTK 119 "Reliability in engineering"
INTRODUCED by Gosstandart of Russia
2 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 7 of April 26, 1995)
Voted to accept:
State name | Name of the national standardization body |
Republic of Belarus | State Standard of the Republic of Belarus |
The Republic of Kazakhstan | State Standard of the Republic of Kazakhstan |
The Republic of Moldova | Moldovastandard |
the Russian Federation | Gosstandart of Russia |
The Republic of Uzbekistan | Uzgosstandart |
Ukraine | State Standard of Ukraine |
3 The standard was developed taking into account the provisions and requirements of the international standards IEC 300-3-1 (1991), IEC 863 (1986) and IEC 706-2 (1990)
4 By Resolution of the Committee of the Russian Federation for Standardization, Metrology and Certification of June 26, 1996 N 430, the interstate standard GOST 27.301-95 was put into effect directly as the state standard of the Russian Federation on January 1, 1997.
5 INSTEAD OF GOST 27.410-87 (in part of clause 2)
6 REVISION
1 area of use
1 area of use
This standard establishes general rules for calculating the reliability of technical objects, requirements for methods and the procedure for presenting the results of reliability calculations.
2 Normative references
This standard uses references to the following standards:
GOST 2.102-68 Unified system for design documentation. Types and completeness of design documents
GOST 27.002-89 Reliability in engineering. Basic concepts. Terms and Definitions
GOST 27.003-90 Reliability in engineering. Composition and general rules for setting reliability requirements
3 Definitions
This standard uses general terms in the field of reliability, the definitions of which are established by GOST 27.002. Additionally, the standard uses the following terms related to the calculation of reliability.
3.1. reliability calculation: The procedure for determining the values of the reliability indicators of an object using methods based on their calculation based on reference data on the reliability of the elements of the object, according to the reliability data of analogue objects, data on the properties of materials and other information available at the time of calculation.
3.2 reliability prediction: A particular case of calculating the reliability of an object based on statistical models that reflect trends in the reliability of analogue objects and / or expert assessments.
3.3 element: An integral part of the object, considered in the calculation of reliability as a whole, not subject to further disaggregation.
4 Fundamentals
4.1 Reliability calculation procedure
The reliability of an object is calculated at the stages of the life cycle and the stages of the types of work corresponding to these stages, established by the reliability assurance program (RP) of the object or documents replacing it.
The PON should establish the calculation goals at each stage of the types of work, the regulatory documents and methods used in the calculation, the timing of the calculation and performers, the procedure for formalizing, presenting and monitoring the calculation results.
4.2 Purpose of reliability calculation
The calculation of the reliability of an object at a certain stage of the types of work, corresponding to a certain stage of its life cycle, may have as its goals:
substantiation of quantitative requirements for reliability to the object or its components;
verification of the feasibility of the established requirements and / or assessment of the probability of achieving the required level of reliability of the object within the established time frame and with the allocated resources, justification of the necessary adjustments to the established requirements;
comparative analysis of the reliability of options for the circuit-constructive construction of an object and the rationale for choosing a rational option;
determination of the achieved (expected) level of reliability of the object and / or its components, including the calculated determination of reliability indicators or distribution parameters of the reliability characteristics of the component parts of the object as initial data for calculating the reliability of the object as a whole;
justification and verification of the effectiveness of the proposed (implemented) measures to improve the design, manufacturing technology, maintenance and repair system of the facility, aimed at improving its reliability;
solving various optimization problems in which reliability indicators act as objective functions, controlled parameters or boundary conditions, including such as optimizing the structure of an object, distributing reliability requirements between indicators of individual components of reliability (for example, reliability and maintainability), calculation of spare parts kits , optimization of maintenance and repair systems, justification of warranty periods and assigned service life (resource) of the object, etc.;
verification of the compliance of the expected (achieved) level of reliability of the object with the established requirements (reliability control), if direct experimental confirmation of their level of reliability is technically impossible or economically inexpedient.
4.3 General calculation scheme
4.3.1 The calculation of the reliability of objects in the general case is a procedure for successive step-by-step refinement of estimates of reliability indicators as the design and manufacturing technology of the object, its operation algorithms, operating rules, maintenance and repair systems, failure criteria and limit states, accumulation of more complete and reliable information about all the factors that determine reliability, and the use of more adequate and accurate calculation methods and calculation models.
4.3.2 Calculation of reliability at any stage of the types of work provided for by the PON plan includes:
identification of the object to be calculated;
determination of the goals and objectives of the calculation at this stage, the range and required values of the calculated reliability indicators;
selection of the calculation method(s) that is adequate to the features of the object, the purposes of the calculation, the availability of the necessary information about the object and the initial data for the calculation;
drawing up calculation models for each indicator of reliability;
obtaining and preliminary processing of initial data for calculation, calculation of the values of the reliability indicators of the object and, if necessary, their comparison with the required ones;
registration, presentation and protection of calculation results.
4.4 Object identification
4.4.1 Identification of an object for calculating its reliability includes obtaining and analyzing the following information about the object, its operating conditions and other factors that determine its reliability:
purpose, scope and functions of the object;
criteria for the quality of functioning, failures and limit states, possible consequences of failures (achievement of the limit state by the object) of the object;
the structure of the object, the composition, interaction and levels of loading of its elements, the possibility of restructuring the structure and / or algorithms for the functioning of the object in case of failures of its individual elements;
availability, types and methods of reservation used in the facility;
a typical object operation model that establishes a list of possible operating modes and functions performed at the same time, the rules and frequency of alternating modes, the duration of the object's stay in each mode and the corresponding operating time, the range and parameters of loads and external influences on the object in each mode;
the planned system of maintenance (TO) and repair of the object, characterized by types, frequency, organizational levels, methods of implementation, technical equipment and material and technical support for its maintenance and repair;
distribution of functions between operators and means of automatic diagnostics (control) and object management, types and characteristics of human-machine interfaces that determine the performance parameters and reliability of operators;
staff qualification level;
the quality of the software used in the facility;
planned technology and organization of production in the manufacture of the object.
4.4.2 The completeness of object identification at the considered stage of its reliability calculation determines the choice of an appropriate calculation method that provides an accuracy acceptable at this stage in the absence or impossibility of obtaining some of the information provided for in 4.4.1.
4.4.3 The sources of information for identifying the object are the design, technological, operational and repair documentation for the object as a whole, its components and components in the composition and sets corresponding to this stage of reliability calculation.
4.5 Calculation methods
4.5.1 Reliability calculation methods subdivide:
according to the composition of the calculated reliability indicators (RI);
according to the basic principles of calculation.
4.5.2 According to the composition of the calculated indicators, calculation methods are distinguished:
reliability,
maintainability,
durability,
persistence,
complex indicators of reliability (methods for calculating availability factors, technical use, maintaining efficiency, etc.).
4.5.3 According to the basic principles for calculating the properties that make up the reliability, or complex indicators of the reliability of objects, there are:
forecasting methods,
structural calculation methods,
physical methods of calculation.
Forecasting methods are based on the use of data on the achieved values and identified trends in the change in the ST of objects similar or close to those considered in terms of purpose, operating principles, circuit design and manufacturing technology, element base and materials used, conditions and modes to assess the expected level of object reliability. operation, principles and methods of reliability management (hereinafter referred to as analogue objects).
Structural calculation methods are based on the representation of an object in the form of a logical (structural-functional) diagram that describes the dependence of the states and transitions of the object on the states and transitions of its elements, taking into account their interaction and the functions they perform in the object, followed by descriptions of the constructed structural model by an adequate mathematical model and calculation PV of the object according to the known characteristics of the reliability of its elements.
Physical calculation methods are based on the use of mathematical models that describe physical, chemical and other processes that lead to failures of objects (to the achievement of the limit state by objects), and the calculation of the ST based on the known loading parameters of the object, the characteristics of the substances and materials used in the object, taking into account the features of its design and manufacturing technology.
The characteristics of the listed methods and recommendations for their use are given in Appendix A.
4.5.4 The method for calculating the reliability of a particular object is selected depending on:
calculation purposes and requirements for the accuracy of determining the object's ST;
the availability and / or the possibility of obtaining the initial information necessary for the application of a certain calculation method;
the level of sophistication of the design and manufacturing technology of the object, its maintenance and repair system, which makes it possible to apply the appropriate calculation models of reliability.
4.5.5 When calculating the reliability of specific objects, it is possible to simultaneously apply various methods, for example, methods for predicting the reliability of electronic and electrical components with the subsequent use of the results obtained as input data for calculating the reliability of the object as a whole or its components by various structural methods.
4.6 Initial data
4.6.1 The initial data for calculating the reliability of an object can be:
a priori data on the reliability of analogue objects, components and components of the object under consideration based on the experience of their use in similar or close conditions;
estimates of reliability indicators (parameters of the laws of distribution of reliability characteristics) of the component parts of the object and parameters of the materials used in the object, obtained experimentally or by calculation directly in the process of development (manufacturing, operation) of the object in question and its components;
calculated and/or experimental estimates of the loading parameters of the component parts and structural elements used in the object.
4.6.2 The sources of initial data for calculating the reliability of an object can be:
standards and technical specifications for the component parts of the object, the components of intersectoral application used in it, substances and materials;
reference books on the reliability of elements, the properties of substances and materials, the standards for the duration (labor intensity, cost) of typical maintenance and repair operations and other information materials;
statistical data (data banks) on the reliability of analogue objects, their constituent elements, the properties of the substances and materials used in them, on the parameters of maintenance and repair operations, collected in the process of their development, manufacture, testing and operation;
the results of strength, electrical, thermal and other calculations of the object and its components, including calculations of the reliability indicators of the component parts of the object.
4.6.3 If there are several sources of initial data for calculating the reliability of an object, the priorities in their use or methods for combining data from different sources should be established in the calculation methodology. In the reliability calculation included in the set of working documentation for the facility, it should be preferable to use the initial data from the standards and specifications for components, elements and materials.
4.7.1 The adequacy of the chosen method of calculation and the constructed calculation models for the purposes and tasks of calculating the reliability of an object is characterized by:
the completeness of the use in the calculation of all available information about the object, its operating conditions, the maintenance and repair system, the reliability characteristics of the components, the properties of the substances and materials used in the object;
the validity of the assumptions and assumptions adopted in the construction of models, their influence on the accuracy and reliability of the estimates of the ST;
the degree of compliance of the level of complexity and accuracy of the calculation models with the reliability of the object with the available accuracy of the initial data for the calculation.
4.7.2 The degree of adequacy of models and methods for calculating reliability is assessed by:
comparison of the results of calculation and experimental evaluation of the ST of objects-analogues, for which similar models and methods of calculation were used;
studies of the sensitivity of models to possible violations of the assumptions and assumptions adopted in their construction, as well as to errors in the initial data for calculation;
examination and approbation of the applied models and methods, carried out in the prescribed manner.
4.8 Requirements for calculation methods
4.8.1 To calculate the reliability of objects, the following are used:
standard calculation methods developed for a group (kind, type) of objects that are homogeneous in purpose and principles of ensuring the reliability of objects, drawn up in the form of relevant regulatory documents (state and industry standards, enterprise standards, etc.);
calculation methods developed for specific objects, the design features and / or conditions of use of which do not allow the use of standard reliability calculation methods. These methods, as a rule, are included directly in the reporting documents for the calculation of reliability or are issued in the form of separate documents included in the documentation set of the corresponding stage of the development of the object.
4.8.2 A typical reliability calculation method should contain:
characteristics of the objects to which the methodology applies, in accordance with the rules for their identification established by this standard;
a list of calculated PV of the object as a whole and its components, methods used to calculate each indicator;
standard models for calculating the ST and the rules for their adaptation for calculating the reliability of specific objects, the calculation algorithms corresponding to these models and, if available, software tools;
methods and corresponding techniques for assessing the parameters of loading of the component parts of objects taken into account in reliability calculations;
requirements for initial data for calculating reliability (sources, composition, accuracy, reliability, presentation form) or directly the initial data themselves, methods for combining heterogeneous initial data for calculating reliability obtained from different sources;
decision rules for comparing the calculated PV values with the required ones, if the calculation results are used to control the reliability of objects;
methods for estimating errors in the calculation of ST, introduced by the assumptions and assumptions adopted for the models and calculation methods used;
methods for assessing the sensitivity of calculation results to violations of the accepted assumptions and / or to errors in the initial data;
requirements for the form of presentation of the results of the calculation of the ST and the rules for protecting the results of the calculation at the relevant checkpoints of the ST and during the examination of projects of facilities.
4.8.3 The methodology for calculating the reliability of a particular object should contain:
information about the object, providing its identification for the calculation of reliability in accordance with the requirements of this standard;
nomenclature of calculated PV and their required values;
models for calculating each ST, the assumptions and assumptions adopted in their construction, the corresponding algorithms for calculating ST and the software used, estimates of errors and sensitivity of the selected (built) models;
initial data for calculation and sources of their receipt;
methods for assessing the loading parameters of an object and its components or directly assessing these parameters with reference to the relevant results and methods of strength, thermal, electrical and other calculations of the object.
4.9 Presentation of calculation results
4.9.1 The results of the calculation of the reliability of the object are drawn up in the form of a section of the explanatory note to the corresponding project (outline, technical) or in the form of an independent document (PP according to GOST 2.102, report, etc.) containing:
goals and methodology (link to the relevant standard methodology) of calculation;
calculated values of all PV and conclusions on their compliance with the established requirements for the reliability of the facility;
identified shortcomings in the design of the facility and recommendations for their elimination with estimates of the effectiveness of the proposed measures in terms of their impact on the level of reliability;
a list of components and elements that limit the reliability of the object or for which there are no necessary data for calculating the PV, proposals for including additional measures to increase (in-depth study) of their reliability or to replace them with more reliable ones (worked out and tested);
conclusion on the possibility of moving to the next stage of the object development with the achieved calculated level of its reliability.
4.9.3 Estimated load ratings, conclusions on their compliance with the established requirements and the possibility of moving to the next stage of the types of work on the development (putting into production) of the object, recommendations for improvements to improve its reliability are included in the acceptance test report, if a decision is made to control reliability object by calculation method.
APPENDIX A (informative). RELIABILITY CALCULATION METHODS AND GENERAL RECOMMENDATIONS FOR THEIR APPLICATION
APPENDIX A
(reference)
1 Reliability prediction methods
1.1 Forecasting methods are used:
to justify the required level of reliability of objects in the development of technical specifications and / or to assess the probability of achieving the specified PV in the development of technical proposals and analysis of the requirements of the TOR (contract). An example of the appropriate methods for predicting the maintainability of objects is contained in MP 252-87;
for an approximate assessment of the expected level of reliability of objects at the early stages of their design, when there is no necessary information for the application of other methods for calculating reliability. An example of a methodology for predicting the reliability indicators of radio-electronic equipment units, depending on its purpose and the number of elements (groups of active elements) used in it, is contained in the American military standard MIL-STD-756A;
to calculate the failure rates of mass-produced and new electronic and electrical components of various types, taking into account the level of their loading, manufacturing quality, areas of application of the equipment in which the elements are used. Examples of relevant methods are contained in the American military reference book MIL-HDBK-217 and domestic reference books on the reliability of IEP for general industrial and special purposes;
to calculate the parameters of typical tasks and operations of maintenance and repair of objects, taking into account the design characteristics of the object, which determine its maintainability. Examples of relevant techniques are contained in MP 252-87 and the US military reference MIL-HDBK-472.
1.2 To predict the reliability of objects, the following are used:
methods of heuristic forecasting (peer review);
forecasting methods based on statistical models;
combined methods.
Heuristic forecasting methods are based on statistical processing of independent estimates of the values of the expected ST of the object being developed (individual forecasts) given by a group of qualified specialists (experts) based on the information provided by them about the object, its operating conditions, the planned manufacturing technology and other data available at the time of the assessment. . A survey of experts and statistical processing of individual forecasts of ST are carried out by methods generally accepted for expert evaluation of any quality indicators (for example, the Delphi method).
Forecasting methods based on statistical models are based on extra- or interpolation of dependencies that describe the identified trends in the change in the ST of analogue objects, taking into account their design and technological features and other factors, information about which is known for the object under development or can be obtained at the time of the assessment. Models for forecasting are built according to the data on the ST and the parameters of analogous objects using known statistical methods (multivariate regression or factor analysis, methods of statistical classification and pattern recognition).
Combined methods are based on the combined use of forecasting methods based on statistical models and heuristic methods for predicting the reliability of objects, followed by comparison of the results. At the same time, heuristic methods are used to assess the possibility of extrapolation of the statistical models used and to refine the forecast for them of the ST. The use of combined methods is advisable in cases where there is reason to expect qualitative changes in the level of reliability of objects that are not reflected by the corresponding statistical models, or when the number of analogue objects is insufficient for the use of only statistical methods.
2 Structural methods for calculating reliability
2.1 Structural methods are the main methods for calculating the reliability, maintainability and complex PV indicators in the process of designing objects that can be disaggregated into elements, the reliability characteristics of which are known at the time of the calculations or can be determined by other methods (forecasting, physical, according to statistical data collected in the process their use under similar conditions). These methods are also used to calculate the durability and persistence of objects whose limit state criteria are expressed in terms of the durability (storability) parameters of their elements.
2.2 Calculation of ST by structural methods generally includes:
representation of the object in the form of a block diagram that describes the logical relationships between the states of the elements and the object as a whole, taking into account structural and functional relationships and interaction of elements, the adopted maintenance strategy, types and methods of redundancy and other factors;
description of the constructed structural diagram of reliability (RSS) of the object by an adequate mathematical model that allows, within the framework of the introduced assumptions and assumptions, to calculate the PV of the object according to the data on the reliability of its elements under the considered conditions of their application.
2.3 The following can be used as structural diagrams of reliability:
structural block diagrams of reliability, representing an object in the form of a set of elements connected in a certain way (in the sense of reliability) (IEC 1078 standard);
object fault trees representing a graphical display of cause-and-effect relationships that cause certain types of its failures (IEC 1025 standard);
graphs (diagrams) of states and transitions that describe the possible states of an object and its transitions from one state to another in the form of a set of states and transitions of its elements.
2.4 Mathematical models used to describe the corresponding SSN are determined by the types and complexity of these structures, the assumptions made regarding the types of distribution laws for the reliability characteristics of elements, the accuracy and reliability of the initial data for calculation, and other factors.
The most commonly used mathematical methods for calculating ST are considered below, which does not exclude the possibility of developing and applying other methods that are more adequate to the structure and other features of the object.
2.5 Methods for calculating the reliability of non-recoverable objects of type I (according to the classification of objects in accordance with GOST 27.003).
As a rule, to describe the reliability of such objects, reliability block diagrams are used, the rules for the compilation and mathematical description of which are established by IEC 1078. In particular, the specified standard establishes:
methods of direct calculation of the probability of non-failure operation of an object (FBR) according to the corresponding parameters of the elements' non-failure operation for the simplest parallel-series structures;
methods for calculating FBGs for more complex structures belonging to the class of monotonic ones, including the method of direct enumeration of states, the method of minimal paths and sections, the method of expansion with respect to any element.
To calculate indicators such as the average time to failure of an object in these methods, the method of direct or numerical integration of the distribution of time to failure of an object, which represents the composition of the corresponding distributions of time to failure of its elements, is used. If information about the distribution of time to failure of the elements is incomplete or unreliable, then various boundary estimates of the object's PV are used, known from reliability theory.
In the particular case of a non-recoverable system with various redundancy methods and with an exponential distribution of time to failure of elements, its structural display in the form of a transition graph and its mathematical description using a Markov process are used.
When used to structurally describe fault trees in accordance with IEC 1025, the respective failure probabilities are calculated using the Boolean representation of the fault tree and the minimum cut method.
2.6 Methods for calculating the reliability and complex duty cycles of restored objects of type I
A universal calculation method for objects of any structure and for any sections of the distribution of operating time between failures and recovery times of elements, for any strategies and methods of restoration and prevention, is the method of statistical modeling, in the general case, including:
synthesis of a formal model (algorithm) for the formation of a sequence of random events occurring during the operation of an object (failures, restorations, switching to a reserve, the beginning and end of maintenance);
development of software for the implementation on a computer of the compiled algorithm and calculation of the object's ST;
conducting a simulation experiment on a computer by repeatedly implementing a formal model that provides the required accuracy and reliability of the calculation of ST.
The method of statistical modeling for calculating reliability is used in the absence of adequate analytical models from among those considered below.
For redundant sequential structures with restoration and arbitrary methods of element redundancy, Markov models are used to describe the corresponding state graphs (diagrams).
In some cases, for objects with non-exponential distributions of operating time and recovery time, the non-Markov problem of calculating the ST can be reduced to a Markov one by introducing fictitious states of the object into its transition graph in a certain way.
Another effective method for calculating the ST of objects with a reserve is based on presenting their operating time between failures as the sum of a random number of random terms and directly calculating the ST of objects without using the methods of the theory of random processes.
2.7 Methods for calculating maintainability indicators
Methods for calculating maintainability indicators in the general case are based on the presentation of the maintenance or repair process of a certain type as a set of individual tasks (operations), the probabilities and goals of which are determined by the reliability (durability) indicators of objects and the adopted maintenance and repair strategy, and the duration (labor intensity, cost) performance of each task depends on the constructive suitability of the object for maintenance (repair) of this type.
In particular, when calculating the maintainability indicators of objects during current unscheduled repairs, the distribution of time (labor input, cost) of its restoration represents the composition of the distributions of costs for individual restoration tasks, taking into account the expected probability of each task being completed for a certain period of operation of the object. These probabilities can be calculated, for example, using fault trees, and the cost distribution parameters for performing individual tasks are calculated using one of the methods established, for example, MP 252-87 (standard-factor, regression models, etc.).
The general calculation scheme includes:
compiling (for example, using AVPKO methods according to GOST 27.310) a list of possible object failures and assessing their probabilities (intensities);
selection from the compiled list by the method of stratified random sampling of a sufficiently representative number of tasks and calculation of the parameters of the distributions of their duration (labor intensity, cost). As such distributions, a truncated normal or alpha distribution is usually used;
construction of an empirical distribution of costs for the current repair of an object by adding, taking into account the probabilities of failures, the distributions of costs for individual tasks and smoothing it using the appropriate theoretical distribution (log-normal or gamma distribution);
calculation of indicators of maintainability of the object according to the parameters of the selected distribution law.
2.8 Methods for calculating the reliability indicators of objects of type II (according to the classification of GOST 27.003)
For objects of this type, a PN of the "efficiency conservation factor" () type is used, in the calculation of which the general principles for calculating the reliability of objects of type I are preserved, but each state of the object, determined by the set of states of its elements or each possible trajectory in the state space of the elements, must be set in accordance with a certain value of the share of retained nominal efficiency from 0 to 1 (for objects of type I, the efficiency in any state can take only two possible values: 0 or 1).
There are two main calculation methods:
state averaging method (analogous to the direct state enumeration method) used for short-term objects performing tasks whose duration is such that the probability of changing the state of the object during the task execution can be neglected and only its initial state can be taken into account;
trajectory averaging method used for long-term objects, the duration of which tasks is such that the probability of changing the state of the object during their execution due to failures and restorations of elements cannot be neglected. In this case, the process of functioning of the object is described by the implementation of one of the possible trajectories in the state space.
There are also some special cases of calculation schemes for determining , used for systems with certain types of efficiency functions, for example:
systems with an additive performance indicator, each element of which makes a certain independent contribution to the output effect from the application of the system;
systems with a multiplicative efficiency indicator obtained as a product of the corresponding performance indicators of subsystems;
systems with redundant functions;
systems that perform a task in several possible ways using different combinations of elements involved in the task by each of them;
symmetrical branching systems;
systems with intersecting coverage areas, etc.
In all the schemes listed above, systems are represented by a function of its subsystems or PN elements.
The most fundamental point in the calculations is the evaluation of the efficiency of the system in various states or in the implementation of various trajectories in the state space, carried out analytically, or by modeling, or experimentally directly on the object itself or its full-scale models (layouts).
3 Physical methods for calculating reliability
3.1 Physical methods are used to calculate the reliability, durability and persistence of objects for which the mechanisms of their degradation under the influence of various external and internal factors are known, leading to failures (limiting states) during operation (storage).
3.2 The methods are based on the description of the corresponding degradation processes with the help of adequate mathematical models that allow calculating the ST taking into account the design, manufacturing technology, modes and operating conditions of the object according to reference or experimentally determined physical and other properties of substances and materials used in the object.
In the general case, these models for one leading degradation process can be represented by a model of emissions of some random process beyond the boundaries of the admissible area of its existence, and the boundaries of this area can also be random and correlated with the specified process (non-exceeding model).
In the presence of several independent degradation processes, each of which generates its own distribution of the resource (time to failure), the resulting resource distribution (time to failure of the object) is found using the "weakest link" model (distribution of the minimum of independent random variables).
3.3 The components of non-exceedance models can have different physical nature and, accordingly, be described by different types of distributions of random variables (random processes), and can also be in damage accumulation models. This is the reason for the wide variety of non-exceedance models used in practice, and only in relatively rare cases do these models allow a direct analytical solution. Therefore, the main method for calculating the reliability of non-exceeding models is statistical modeling.
APPENDIX B (informative). List of reference books, normative and methodical documents on reliability calculation
APPENDIX B
(reference)
1 B.A. Kozlov, I.A. Ushakov. Handbook for calculating the reliability of radio electronics and automation equipment. M.: Soviet radio, 1975. 472 p.
2 Reliability of technical systems. Handbook, ed. I.A.Ushakova. Moscow: Radio and communication, 1985. 608 p.
3 Reliability and efficiency in engineering. Handbook in 10 volumes.
T.2 ed. B.V. Gnedenko. M.: Mashinostroenie, 1987. 280 s;
Vol. 5, ed. V.I.Patrushev and A.I.Rembeza. M.: Mashinostroenie, 1988. 224 p.
4 B.F. Khazov, B.A. Didusev. Handbook for calculating the reliability of machines at the design stage. M.: Mashinostroenie, 1986. 224 p.
5 IEC 300-3-1 (1991) Reliability management. Part 3. Guidelines. Section 1. Overview of reliability analysis methods.
6 IEC standard 706-2 (1991) Guidelines for ensuring the maintainability of hardware. Part 2, section 5. Maintainability analysis at the design stage.
7 IEC standard 863 (1986) Presentation of reliability, maintainability and availability prediction results.
8 IEC 1025 (1990) Fault tree analysis.
9 IEC 1078 (1991) Reliability analysis methods. Reliability calculation method using block diagrams.
10 RD 50-476-84 Guidelines. Reliability in technology. Interval assessment of the reliability of a technical object based on the results of tests of components. General provisions.
11 RD 50-518-84 Guidelines. Reliability in technology. General requirements for the content and forms of presentation of reference data on the reliability of components for cross-industry use.
12 MP 159-85 Reliability in engineering. Choice of types of distributions of random variables. Guidelines.
13 MP 252-87 Reliability in engineering. Calculation of maintainability indicators during product development. Guidelines.
14 Р 50-54-82-88 Reliability in engineering. The choice of ways and methods of reservation.
15 GOST 27.310-95 Reliability in engineering. Analysis of the types, consequences and criticality of failures. Basic Provisions .
16 US military standard MIL-STD-756A. Modeling and forecasting reliability.
17 US Military Standards Handbook MIL-HDBK-217E. Forecasting the reliability of elements of radio-electronic equipment.
18 US Military Standards Handbook MIL-HDBK-472. Maintainability prediction.
The text of the document is verified by:
official publication
Reliability in technology: Sat. GOSTs. -
Moscow: IPK Standards Publishing House, 2002
GOST 27.301-95
INTERSTATE STANDARD
RELIABILITY IN TECHNOLOGY
RELIABILITY CALCULATION
MAIN PROVISIONS
Official edition
INTERSTATE COUNCIL FOR STANDARDIZATION, METROLOGY AND CERTIFICATION
Foreword
1 DEVELOPED MTK 119 "Reliability in Engineering"
INTRODUCED by Gosstandart of Russia
2 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 7-95 of April 26, 1995)
3 The standard was developed taking into account the provisions and requirements of the international standards IEC 300-3-1 (1991), IEC 863 (1986) and IEC 706-2 (1990)
4 By the Decree of the Committee of the Russian Federation for Standardization, Metrology and Certification dated June 26, 1996 No. 430, the interstate standard GOST 27.301-95 was put into effect "directly as the state standard of the Russian Federation on January 1, 1997.
5 INSTEAD OF GOST 27.410-87 (in part of clause 2)
© IPK Standards Publishing House, 1996
This standard cannot be fully or partially reproduced, replicated and distributed as an official publication on the territory of the Russian Federation without the permission of the State Standard of Russia
1 Scope .................................................1
3 Definitions..............................................1
4 Fundamentals....................................2
4.1 Reliability calculation procedure....................................2
4.2 Objectives of the reliability calculation....................................2
4.3 General scheme of calculation....................................3
4.4 Object identification...............................................3
4.5 Calculation Methods....................................4
4.6 Initial data...............................................6
4.8 Requirements for calculation methods ............................... 7
4.9 Presentation of calculation results ..................................9
Annex A Reliability calculation methods and general recommendations for their application ..................................10
Appendix B List of reference books, regulatory and methodological documents for the calculation of reliability ..... 15
INTERSTATE STANDARD
Reliability in engineering
RELIABILITY CALCULATION
Key points
Dependability in technics. Dependability prediction. basic principles
Introduction date 1997-01-01
1 AREA OF USE
This standard establishes general rules for calculating the reliability of technical objects, requirements for methods and the procedure for presenting the results of reliability calculations.
GOST 2.102-68 ESKD. Types and completeness of design documents
GOST 27.002-89 Reliability in engineering. Basic concepts. Terms and Definitions
GOST 27.003-90 Reliability in engineering. Composition and general rules for setting reliability requirements
GOST 27.310-95 Reliability in technology. Analysis of the types, consequences and criticality of failures. Key points
3 DEFINITIONS
This standard uses general terms in the field of reliability, the definitions of which are established by GOST 27.002. Additionally, the standard uses the following terms related to the calculation of reliability.
Official Edition ★
3.1. Reliability calculation - a procedure for determining the values of object reliability indicators using methods based on their calculation based on reference data on the reliability of object elements, on the basis of data on the reliability of analogue objects, data on the properties of materials and other information available at the time of calculation.
3.2 Reliability prediction - a special case of calculating the reliability of an object based on statistical models that reflect trends in the reliability of analogue objects and/or expert assessments.
3.3 Element - an integral part of the object, considered in the calculation of reliability as a whole, not subject to further disaggregation.
4 MAIN CONDITIONS
4.1 Reliability calculation procedure
The reliability of an object is calculated at the stages of the life cycle and the stages of the types of work corresponding to these stages, established by the reliability assurance program (RP) of the object or documents replacing it.
The PON should establish the calculation goals at each stage of the types of work, the regulatory documents and methods used in the calculation, the timing of the calculation and performers, the procedure for formalizing, presenting and monitoring the calculation results.
4.2 Purpose of reliability calculation
The calculation of the reliability of an object at a certain stage of the types of work, corresponding to a certain stage of its life cycle, may have as its goals:
substantiation of quantitative requirements for reliability to the object or its components;
verification of the feasibility of the established requirements and / or assessment of the probability of achieving the required level of reliability of the object within the established time frame and with the allocated resources, justification of the necessary adjustments to the established requirements;
comparative analysis of the reliability of options for the circuit-constructive construction of an object and the rationale for choosing a rational option;
determination of the achieved (expected) level of reliability of the object and / or its components, including the calculated determination of reliability indicators or distribution parameters of the reliability characteristics of the component parts of the object as initial data for calculating the reliability of the object as a whole;
substantiation and verification of the effectiveness of the proposed (implemented) measures to improve the design, manufacturing technology, maintenance and repair system of the facility, aimed at improving its reliability;
solving various optimization problems in which reliability indicators act as objective functions, controlled parameters or boundary conditions, including such as optimizing the structure of an object, distributing reliability requirements between indicators of individual components of reliability (for example, reliability and maintainability), calculation of spare parts kits , optimization of maintenance and repair systems, justification of warranty periods and assigned service life (resource) of the object, etc.;
verification of the compliance of the expected (achieved) level of reliability of the object with the established requirements (reliability control), if direct experimental confirmation of their level of reliability is technically impossible or economically inexpedient.
4.3 General calculation scheme
4.3.1 The calculation of the reliability of objects in the general case is a procedure for successive step-by-step refinement of estimates, reliability indicators as the design and manufacturing technology of the object, its operation algorithms, operating rules, maintenance and repair systems, failure criteria and limit states, accumulation of more complete and reliable information about all factors that determine reliability, and the use of more adequate and accurate calculation methods and calculation models.
4.3.2 Calculation of reliability at any stage of the types of work provided for by the PON plan includes:
identification of the object to be calculated; determination of the goals and objectives of the calculation at this stage, the range and required values of the calculated reliability indicators;
selection of the calculation method(s) that is adequate to the features of the object, the purposes of the calculation, the availability of the necessary information about the object and the initial data for the calculation;
drawing up calculation models for each indicator of reliability; obtaining and preliminary processing of initial data for calculation, calculation of the values of the reliability indicators of the object and, if necessary, their comparison with the required ones;
registration, presentation and protection of calculation results.
4.4 Object identification
4.4.1 Identification of an object for calculating its reliability includes obtaining and analyzing the following information about the object, its operating conditions and other factors that determine its reliability:
purpose, scope and functions of the object; criteria for the quality of functioning, failures and limit states, possible consequences of failures (achievement of the limit state by the object) of the object;
the structure of the object, the composition, interaction and levels of the loaded elements included in it, the possibility of restructuring the structure and / or algorithms for the functioning of the object in case of failures of its individual elements;
availability, types and methods of reservation used in the facility; a typical object operation model that establishes a list of possible operating modes and functions performed at the same time, the rules and frequency of alternating modes, the duration of the object's stay in each mode and the corresponding operating time, the range and parameters of loads and external influences on the object in each mode;
the planned system of maintenance (TO) and repair of the object, characterized by types, frequency, organizational levels, methods of implementation, technical equipment and material and technical support for its maintenance and repair;
distribution of functions between operators and means of automatic diagnostics (control) and object management, types and characteristics of human-machine interfaces that determine the performance parameters and reliability of operators; staff qualification level;
the quality of the software used in the facility; planned technology and organization of production in the manufacture of the object.
4.4.2 The completeness of object identification at the considered stage of its reliability calculation determines the choice of an appropriate calculation method that provides an accuracy acceptable at this stage in the absence or impossibility of obtaining some of the information provided for in 4.4.1.
4.4.3 The sources of information for identifying the object are the design, technological, operational and repair documentation for the object as a whole, its components and components in the composition and sets corresponding to this stage of reliability calculation.
4.5 Calculation methods
4.5.1 Reliability calculation methods subdivide:
according to the composition of the calculated reliability indicators (RI); according to the basic principles of calculation.
4.5.2 According to the composition of the calculated indicators, calculation methods are distinguished:
reliability,
maintainability,
durability,
persistence,
complex indicators of reliability (methods for calculating availability factors, technical use, maintaining efficiency, etc.).
4.5.3 According to the basic principles for calculating the properties that make up the reliability, or complex indicators of the reliability of objects, there are:
forecasting methods, structural methods of calculation, physical methods of calculation.
Forecasting methods are based on the use of data on the achieved values and identified trends in the change in the ST of objects that are similar or close to those considered in terms of purpose, operating principles, circuit design and manufacturing technology, element base and materials used, conditions and operating modes, principles and methods of reliability management (hereinafter referred to as analogue objects).
Structural calculation methods are based on the representation of an object in the form of a logical (structural-functional) diagram that describes the dependence of the states and transitions of the object on the states and transitions of its Elements, taking into account their interaction and the functions they perform in the object, followed by descriptions of the constructed structural model by an adequate mathematical model and calculation PV of the object according to the known characteristics of the reliability of its elements.
Physical calculation methods are based on the use of mathematical models that describe physical, chemical and other processes that lead to failures of objects (to the achievement of the limit state by objects), and the calculation of the ST based on the known loading parameters of the object, the characteristics of the substances and materials used in the object, taking into account the features of its design and manufacturing technology.
4.5.4 The method for calculating the reliability of a particular object is selected depending on:
calculation purposes and requirements for the accuracy of determining the object's ST; the availability and / or the possibility of obtaining the initial information necessary for the application of a certain calculation method;
the level of sophistication of the design and manufacturing technology of the object, its maintenance and repair system, which makes it possible to apply the appropriate calculation models of reliability.
4.5.5 When calculating the reliability of specific objects, it is possible to simultaneously apply various methods, for example, methods for predicting the reliability of electronic and electrical components with the subsequent use of the results obtained as input data for calculating the reliability of the object as a whole or its components by various structural methods.
4.6 Initial data
4.6.1 The initial data for calculating the reliability of an object can be: a priori data on the reliability of analogue objects, composite
parts and components of the object under consideration according to the experience of their use in similar or close conditions;
estimates of reliability indicators (parameters of the laws of distribution of reliability characteristics) of the component parts of the object and parameters of the materials used in the object, obtained experimentally or by calculation directly in the process of development (manufacturing, operation) of the object in question and its components;
calculated and/or experimental estimates of the loading parameters of the component parts and structural elements used in the object.
4.6.2 The sources of initial data for calculating the reliability of an object can be:
standards and technical specifications for the component parts of the object, the components of intersectoral application used in it, substances and materials;
reference books on the reliability of elements, the properties of substances and materials, the standards for the duration (labor intensity, cost) of typical maintenance and repair operations and other information materials;
statistical data (data banks) on the reliability of analogue objects, their constituent elements, the properties of the substances and materials used in them, on the parameters of maintenance and repair operations, collected in the process of their development, manufacture, testing and operation;
the results of strength, electrical, thermal and other calculations of the object and its components, including calculations of the reliability indicators of the component parts of the object.
4.6.3 If there are several sources of initial data for calculating the reliability of an object, the priorities in their use or methods for combining data from different sources should be established in the calculation methodology. In the reliability calculation included in the set of working documentation for the facility, it should be preferable to use the initial data from the standards and specifications for components, elements and materials.
4.7.1 The adequacy of the chosen method of calculation and the constructed calculation models for the purposes and tasks of calculating the reliability of an object is characterized by:
completeness of use in the calculation of all available information
about the object, the conditions of its operation, the maintenance and repair system, the reliability characteristics of the components, the properties of the substances and materials used in the object;
the validity of the assumptions and assumptions adopted in the construction of models, their influence on the accuracy and reliability of the estimates of the ST;
the degree of compliance of the level of complexity and accuracy of the calculation models with the reliability of the object with the available accuracy of the initial data for the calculation.
4.7.2 The degree of adequacy of models and methods for calculating reliability is assessed by:
comparison of the results of calculation and experimental evaluation of the ST of objects-analogues, for which similar models and methods of calculation were used;
studies of the sensitivity of models to possible violations of the assumptions and assumptions adopted in their construction, as well as to errors in the initial data for calculation;
examination and approbation of the applied models and methods, carried out in the prescribed manner.
4.8 Requirements for calculation methods
4.8.1 To calculate the reliability of objects, the following are used: typical calculation methods developed for a group (kind, type) of objects that are homogeneous in purpose and principles of ensuring the reliability of objects, drawn up in the form of relevant regulatory documents (state and industry standards, enterprise standards, etc.);
calculation methods developed for specific objects, the design features and / or conditions of use of which do not allow the use of standard reliability calculation methods. These methods, as a rule, are included directly in the reporting documents for the calculation of reliability or are issued in the form of separate documents included in the documentation set of the corresponding stage of the development of the object.
4.8.2 A typical methodology for calculating reliability should contain: a description of the objects to which the methodology applies,
in accordance with the rules for their identification established by this standard;
a list of calculated PV of the object as a whole and its components, methods used to calculate each indicator;
standard models for calculating the ST and the rules for their adaptation for calculating the reliability of specific objects, the calculation algorithms corresponding to these models and, if available, software tools;
methods and corresponding techniques for assessing the parameters of loading of the components of objects taken into account in reliability calculations;
requirements for initial data for calculating reliability (sources, composition, accuracy, reliability, presentation form) or directly the initial data themselves, methods for combining heterogeneous initial data for calculating reliability obtained from different sources;
decision rules for comparing the calculated PV values with the required ones, if the calculation results are used to control the reliability of objects;
methods for estimating errors in the calculation of ST, introduced by the assumptions and assumptions adopted for the models and calculation methods used;
methods for assessing the sensitivity of calculation results to violations of the accepted assumptions and / or to errors in the initial data;
requirements for the form of presentation of the results of the calculation of the ST and the rules for protecting the results of the calculation at the relevant checkpoints of the ST and during the examination of projects of facilities.
4.8.3 The methodology for calculating the reliability of a particular object should contain;
information about the object, providing its identification for the calculation of reliability in accordance with the requirements of this standard;
nomenclature of calculated PV and their required values; models for calculating each ST, the assumptions and assumptions adopted in their construction, the corresponding algorithms for calculating ST and the software used, estimates of errors and sensitivity of the selected (built) models;
initial data for calculation and sources of their receipt;
methods for assessing the loading parameters of an object and its components or directly assessing these parameters with reference to the relevant results and methods of strength, thermal, electrical and other calculations of the object.
4.9 Presentation of calculation results
4.9.1 The results of the calculation of the reliability of the object are drawn up in the form of a section of the explanatory note to the corresponding project (outline, technical) or an independent document (PP according to GOST 2.102, report, etc.) containing:
calculated values of all PV and conclusions on their compliance with the established requirements for the reliability of the facility;
identified shortcomings in the design of the facility and recommendations for their elimination with estimates of the effectiveness of the proposed measures in terms of their impact on the level of reliability;
a list of components and elements that limit the reliability of the object or for which there are no necessary data for calculating the PV, proposals for including additional measures to increase (in-depth study) of their reliability or to replace them with more reliable ones (worked out and tested);
conclusion on the possibility of moving to the next stage of the object development with the achieved calculated level of its reliability.
4.9.3 Estimated load ratings, conclusions on their compliance with the established requirements and the possibility of moving to the next stage of the types of work on the development (putting into production) of the object, recommendations for improvements to improve its reliability are included in the acceptance test report, if a decision is made to control reliability object by calculation method.
APPENDIX A (informative)
BY THEIR APPLICATION
1 Reliability prediction methods
1.1 Forecasting methods are used:
to justify the required level of reliability of objects in the development of technical specifications and / or to assess the probability of achieving the specified PV in the development of technical proposals and analysis of the requirements of the TOR (contract). An example of the relevant methods for predicting the maintainability of objects is contained in MP 252-
for an approximate assessment of the expected level of reliability of objects at the early stages of their design, when there is no necessary information for the application of other methods for calculating reliability. An example of a methodology for predicting the reliability indicators of radio-electronic equipment units, depending on its purpose and the number of elements (groups of active elements) used in it, is contained in the American military standard M1L-STD-756A;
to calculate the failure rates of mass-produced and new electronic and electrical components of various types, taking into account the level of their loading, manufacturing quality, areas of application of the equipment in which the elements are used. Examples of relevant methods are contained in the American military reference book MIL-HDBK-217 and domestic reference books on the reliability of IEP for general industrial and special purposes;
to calculate the parameters of typical tasks and operations of maintenance and repair of objects, taking into account the design characteristics of the object, which determine its maintainability. Examples of relevant techniques are contained in MP 252-87 and the US military reference MIL-HDBK-472.
12 To predict the reliability of objects used;
methods of heuristic forecasting (peer review);
forecasting methods based on statistical models;
combined methods.
Heuristic forecasting methods are based on statistical processing of independent estimates of the values of the expected ST of the object being developed (individual forecasts) given by a group of qualified specialists (experts) based on the information provided by them about the object, its operating conditions, the planned manufacturing technology and other data available at the time of the estimates Questioning of experts and statistical processing of individual forecasts of PI is carried out by methods generally accepted in the expert assessment of any quality indicators (for example, the Delphi method).
Forecasting methods based on statistical models are based on extra- or interpolation of dependencies that describe the identified trends in changes in the ST of analogue objects, taking into account their design and technological features and other factors, information about which is known for the object under development or can be obtained at the time of the estimates. Models for forecasting are built according to the data on the ST and the parameters of analogue objects using known statistical methods (multivariate regression or factor analysis, methods of statistical classification and pattern recognition)
Combined methods are based on the combined use of forecasting methods based on statistical models and heuristic methods for predicting the reliability of objects, followed by comparison of the results. At the same time, heuristic methods are used to assess the possibility of extrapolating the statistical models used and >accurate the forecast based on them PI. The use of combined methods is advisable in cases where there is reason to expect qualitative changes in the level of reliability of objects that are not reflected by the corresponding statistical models, or when only statistical methods are insufficient for using only statistical methods. the number of analog objects.
2 Structural methods for calculating reliability
2.1 Structural methods are the main methods for calculating the reliability, maintainability and complex PV indicators in the process of designing objects that can be disaggregated into elements, the reliability characteristics of which are known at the time of the calculations or can be determined by other methods (forecasting, physical, according to statistical data collected in the process their use under similar conditions). These methods are also used to calculate the durability and persistence of objects, the criteria for the limiting state of which are expressed through the parameters of durability (storability) of their elements.
2 2 Calculation of PV by structural methods generally includes: representation of an object in the form of a block diagram that describes the logical relationships between the states of the elements and the object as a whole, taking into account structural and functional relationships and interaction of elements, the adopted maintenance strategy, types and methods of redundancy and other factors,
description of the constructed reliability block diagram (RSS) of an object by an adequate mathematical model that allows, within the framework of the introduced assumptions and assumptions, to calculate!. ST of the object according to the data on the reliability of its elements in the considered conditions of their use
2.3 As reliability block diagrams, the following can be used: reliability block diagrams representing an object in the form of a set
certain o6j>a number of connected (in terms of reliability) elements (standard M "-Zh 107l;
failure trees; sv of an object, representing a graphical display of cause-and-effect relationships that cause certain types of its failures (IEC 1025 standard);
graphs (diagrams) of states and transitions that describe the possible states of an object and its transitions from one state to another in the form of a set of states and transitions of its elements.
2.4 Mathematical models used to describe cosh nsts gnukitsi \ 1 "S" P. are determined by the types and complexity of these structures, the assumptions made regarding the types of distribution laws for the reliability characteristics of elements, the accuracy and reliability of the initial data for calculation, and other factors.
Below are the most common mathematical? methods for calculating the ST, which does not exclude the possibility of developing and applying other methods that are more adequate to the structure and other features of the object
2 5 Methods for calculating the non-failure operation of non-recovery of the v s 6 s c to in type I (according to the classification of objects in accordance with GOST 27 003)
As a rule, to describe the reliability of such objects, a block is used (reliability schemes, the rules for compiling and mathematical description of which are established by M "-Zh 1078. In particular, they are established by the specified standard.
methods of direct calculation of the probability of non-failure operation of an object (FBR) according to the corresponding parameters of the elements' non-failure operation for the simplest parallel-series structures;
methods for calculating FBGs for more complex structures belonging to the class of monotonic ones, including the method of direct enumeration of states, the method of minimal paths and sections, the method of expansion with respect to any element.
To calculate indicators such as the average time to failure of an object in these methods, the method of direct or numerical integration of the distribution of time to failure of an object, which represents the composition of the corresponding distributions of time to failure of its elements, is used. F-if the information about the distribution of time to failure of the elements is incomplete or unreliable, then various boundary estimates of the object's PV are used, known from the reliability theory |1-4|
In the particular case of a non-recoverable system with various redundancy methods and with an exponential distribution of time to failure of elements, its structural display in the form of a transition graph and its mathematical description using the Markov process are used.
When used to structurally describe fault trees in accordance with IEC 1025, the respective failure probabilities are calculated using the Boolean representation of the fault tree and the minimum cut method.
2 6 Methods for calculating the reliability and complex duty cycle of recoverable objects of type 1
A universal calculation method for objects of any structure and for any combination of distributions of operating time between failures and recovery times of elements, for any strategies and methods of restoration and prevention, is the method of statistical modeling, in the general case, including:
synthesis of a formal model (algorithm) for the formation of a sequence of random events occurring during the operation of an object (failures, restorations, switching to a reserve, the beginning and end of maintenance);
development of software for the implementation on a computer of the compiled algorithm and calculation of the object's ST;
conducting a simulation experiment on a computer by repeatedly implementing a formal model that provides the required accuracy and reliability of the calculation of ST
The method of statistical modeling for calculating reliability is used in the absence of adequate analytical models from among those considered below.
For redundant sequential structures with restoration and arbitrary methods of redundant elements, Markov models are used to describe the corresponding graphs (diaphmas) of states.
In some cases, for objects with non-exponential distributions of operating time and recovery time, the non-Markov problem of calculating the ST can be reduced to a Markov one by introducing fictitious states of the object into its transition graph in a certain way.
Another effective method for calculating the ST of objects with a reserve is based on presenting their operating time between failures as the sum of a random number of random terms and directly calculating the ST of objects without using the methods of the theory of random processes.
2.7 Methods for calculating maintainability indicators Methods for calculating maintainability indicators in the general case are based on the presentation of the process of maintenance or repair of a certain type as a set of individual tasks (operations), the probabilities and objectives of which are determined by the indicators of reliability (durability) of objects and the adopted maintenance strategy and
repair, and the duration (labor intensity, cost) of each task depends on the structural suitability of the facility for maintenance (repair) of this type. individual recovery tasks, taking into account the expected probability of completing each task for a certain period of operation of the object. The indicated probabilities can be calculated, for example, using fault trees, and the cost distribution parameters for performing individual tasks are calculated using one of the methods established, for example, MP 252-87 ( normative-coefficient, according to regression models, etc.).
The general calculation scheme includes:
compiling (for example, by AVPKO methods according to GOST 27 310) a list of possible object failures and assessing their probabilities (intensities);
selection from the compiled list by the method of stratified random sampling of some fairly representative number of tasks and calculation of the parameters of their duration distributions (labor input, cost). As such distributions, a truncated normal or alpha distribution is usually used;
construction of an empirical distribution of costs for the current repair of an object by adding, taking into account the probabilities of failures, the distributions of costs for individual tasks and smoothing it using the appropriate theoretical distribution (log-rhythmic-normal or gamma distribution),
calculation of indicators of maintainability of an object according to the parameters of the selected distribution law
2.8 Methods for calculating the reliability indicators of objects of the type
1 I (according to the classification of GOST 27 003)
For objects of this type, a PN of the “efficiency conservation factor” (£*)> type is used), the calculation of which preserves the general principles for calculating the reliability of objects of type I, but for each state of the object, determined by the set of states of its elements or each of its possible trajectories in the state space of elements , a certain value of the share of retained nominal efficiency must be assigned from 0 to 1 (for objects of type I, the efficiency in any state can take only two possible values:
There are two main calculation methods
state averaging method (analogous to the direct state enumeration method) used for short-lived objects performing tasks whose duration is such that the probability of changing the state of the object during the task execution can be neglected and only its initial state can be taken into account;
trajectory averaging method used for long-term objects, the duration of which tasks are such that the probability of changing the state of the volume during their execution due to failures cannot be neglected. .^becomings of elements. In this case, the process of the object functioning is described by the implementation of one of the possible trajectories in the state space
There are also some special cases of calculation schemes for determining K*\,. used for systems with certain types of efficiency functions, for example, systems with an additive efficiency indicator, each element of which makes a certain independent contribution "output efs)\u003e skt from the use of the system, system\u003e. a multiplicative performance indicator obtained as a product of the corresponding performance indicators of subsystems; systems with redundant functions;
systems that perform a task in several possible ways using various combinations of elements involved in the task by each of them,
symmetrical branching systems,
systems with intersecting coverage areas, etc.
In all the schemes listed above, the systems are represented by the function A "eff of its subsystems or PN elements.
The most fundamental point in the calculations of A^f is the evaluation of the system efficiency in various states or in the implementation of various trajectories in the state space, carried out analytically, or by modeling, or experimentally directly on the object itself or its full-scale models (mockups).
3 Physical methods for calculating reliability
3 1 Physical methods are used to calculate the reliability, durability and persistence of objects for which the mechanisms of their degradation under the influence of various external and internal factors are known, leading to failures (limiting states) during operation (storage)
3 2 The methods are based on the description of the corresponding degradation processes with the help of adequate mathematical models that make it possible to calculate the ST taking into account the design, manufacturing technology, modes and operating conditions of the object according to reference or experimentally determined physical and other properties of substances and materials used in the object.
In the general case, these models for one leading degradation process can be represented by a model of emissions of some random process beyond the boundaries of the admissible area of its existence, and the boundaries of this area can also be random and correlated with the specified process (non-exceeding model). .
In the presence of several independent degradation processes, each of which generates its own resource distribution (time to failure), the resulting resource distribution (time to failure of an object) is found using the “weakest link” model (distribution of the minimum of independent random variables).
3 3 Components of non-exceedance models can have different physical nature and, accordingly, be described by different types of distributions of random variables (random processes), and can also be in damage accumulation models. This is the reason for the wide variety of non-exceedance models used in practice, and only in relatively rare cases do these models allow a direct analytical solution. Therefore, the main method for calculating the reliability of non-exceeding models is statistical modeling.
APPENDIX B (informative)
LIST OF HANDBOOKS, REGULATORY AND METHODOLOGICAL DOCUMENTS ON RELIABILITY CALCULATION
1 B.A. Koyov, I.A. Ushakov. Handbook for calculating the reliability of radio electronics and automation equipment M: Soviet radio, 1975 472 s
2 Reliability of technical systems. Handbook, ed. I.A. Ushakov. M.: Radio
i svyaz, 1985. 608 p. .
3 Reliability and efficiency in engineering. Handbook in 10 volumes.
Vol. 2, ed. B.V. Gnedenko. M.: Mashinostroenie, 1987. 280 s;
Vol. 5, ed. V I Patrushev; and A.I. Rembeza. M.: Mashinostroenie, 1988 224 p.
4 B.F. Khazov, B. A. Didusev. Handbook for calculating the reliability of machines at the design stage. M.: Mashinostroenie, 1986. 224 p.
5 IEC Standard 300-3-1(1991) Reliability management Part 3 of the Guide Section 1. Overview of reliability analysis methods.
6 IEC Standard 706-2(1991) Guidelines for ensuring the maintainability of hardware. Part 2, Section 5, Maintainability Analysis at the Design Stage
7 IEC 863(1986) Presentation of prediction results for reliability, maintainability and availability
8 IEC 1025(1990) Fault tree analysis.
9 IEC 1078(1991) Methods for reliability analysis. Reliability calculation method using block diagrams.
10 RD 50-476-84 Guidelines. Reliability in engineering Interval assessment of the reliability of a technical object based on the results of tests of components. General provisions.
11 RD 50-518-84 Guidelines. Reliability in engineering General requirements for the content and forms of presentation of reference data on the reliability of components for interbranch applications.
12 MP 159-85 Reliability in engineering Choice of types of distributions of random variables. Guidelines.
13 MR 252-87 Reliability in engineering Calculation of maintainability indicators during product development. Guidelines.
14 Р 50-54-82-88 Reliability in engineering Choice of ways and methods of redundancy.
15 GOST 27.310-95 Reliability in technology. Analysis of the types, consequences and criticality of failures. Basic provisions.
16 US military standard MIL-STD-756A. Modeling and forecasting reliability.
17 US Military Standards Handbook MIL-HDBK-2I7E Prediction of Reliability of Electronic Equipment Elements.
18 US Military Standards Handbook MIL-HDBK-472. Maintainability Prediction
UDC 62-192.001.24:006.354 OKS 21.020 T51 OKSTU 0027
Keywords: reliability, reliability calculation, reliability prediction, calculation procedure, requirements for methods, presentation of results
Editor R. S. Fedorova Technical editor V. N. Prutkova Proofreader M. S. Kabasoni Computer proofing by A. N. Zolotareva
Ed. persons. No. 021007 dated 10.08.95. Handed over to the set 10/14/96. Signed for printing 10.12.96 1.16. Uch.-ed.l. 1.10. Circulation 535 copies. From 4001. Order. 558.
IPK Standards Publishing House 107076, Moscow, Kolodezny per., 14.
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