Reliability prediction procedure

This standard specifies uniform procedures and methods for the reliability prediction of electronic, electrical and other equipment and systems. The complexity of the product can range from the simplest single to a complete system. GB 7827-1987 Reliability Prediction Procedure GB7827-1987 Standard Download Decompression Password: www.bzxz.net
This standard specifies uniform procedures and methods for the reliability prediction of electronic, electrical and other equipment and systems. The complexity of the product can range from the simplest single to a complete system.

1 General Principles
1.1 Scope
National Standard of the People's Republic of China
Reliability prediction procedure
Reliability prediction procedure UDC 621.3 - 192
GB 7827-87
This standard specifies the unified procedures and methods for reliability prediction of electronic and electrical equipment and systems (hereinafter referred to as products). The complexity of products can range from the simplest unit to a complete system. 1.2 The purpose of reliability prediction is to estimate whether a product can meet the specified reliability requirements, so as to provide a measure of product reliability for design decisions. Basic reliability prediction is used to estimate the requirements for maintenance and logistics support due to product unreliability, and mission reliability prediction is used to estimate the probability that a product will complete its specified functions during the execution of its mission. When these two predictions are used at the same time, they can provide a basis for identifying aspects that need special emphasis and attention, and provide a basis for comparing the user cost-effectiveness of different design structures. 2 Cited Standards
GB3187-82 "Basic Terms and Definitions of Reliability" GB7289-87 "Guidelines for Prediction Reports on Reliability, Maintainability and Effectiveness" 3-General Procedure
The following steps are the general procedures for product reliability prediction. 3.1 Define Product
Define the product to specify:
a. Purpose, intended use or mission;
b. Performance parameters and allowable limits;
c. Structural and functional limits;
d. The conditions that constitute mission failure;
e: "Working use model.
3.2 Determine the components of the product
The components of the product are the basic units for structural decomposition of the product. Therefore, the types and descriptions of the components should be provided according to the level of analysis.
3.3 Determine the reliability block diagram
The reliability block diagram is a block diagram that shows the interdependence of all components when the product can successfully complete the task each time it is used. It can express the various series, parallel or complex combinations of the product's mission in a concise and intuitive way. 3.4 Determine environmental information
It is necessary to specify the failure of the components. Environmental information that affects the rate. This information should include specific natural and induced environments related to the events and functions described by the service and working cycle. 3.5 Determination of stress information wwW.bzxz.Net
To determine the operating stresses to which each component is subjected, a stress analysis should be performed based on the available detailed design data. To take into account the effects of applied stresses, the failure rates of the components should be corrected by appropriate factors. The failure rates listed in the estimated report should be marked as estimated, calculated or measured, respectively. Approved by the National Bureau of Standards on June 3, 1987
Implemented on January 1, 1988
3.6 Determination of failure distribution
GB 7827-87
In the calculations, a failure distribution appropriate to the specific product should be used. In the case where the failure distribution of the product is unknown, an exponential, multinomial, Weibull or other distribution may be assumed. The failure distribution used should be stated in the prediction report, and all assumptions should be supported by empirical or statistical tests. 3.7 Determine the failure rate
The failure rate of each component of the product is required for each major event and environment specified in the working use model. All sources of failure information should be approved by the user before use. The basic failure rate calculated from most information sources must be corrected by an appropriate coefficient for the specific product application. The correction factors used should be listed and verified in the prediction report. 3.8 Establish a reliability model
See Chapter 4 of this standard. ||tt| |3.9 Predicted product reliability
Predict product reliability using prediction methods (see Chapter 5 of this standard) and corresponding reliability data. The presentation of the prediction results should be consistent with the specified reliability requirements, and a prediction report should be prepared. 3.10 Preparing a prediction report
See GB7289-87 "Guidelines for Preparing Prediction Reports on Reliability, Maintainability and Effectiveness" 4 Reliability Model
4.1 Basic Reliability Model
The basic reliability model is used for the prediction of basic reliability. The basic reliability model is a series model. Therefore, all components (including those that are purely used to do the product's spare and replacement work) should be treated in series, unless the product has neither a spare nor a replacement operating mode, the basic reliability model cannot be used to estimate the product's mission reliability. The level of detail of the basic reliability model should reach the following product level, that is, there is available information for them, and the piece failure rate data can be used to estimate the impact of maintenance and logistics support on product design. 4.2 Mission Reliability Model
The mission reliability model is used for mission reliability prediction. The mission reliability model is usually a series-parallel model or a more complex model.
The steps to establish a mission reliability model are as follows: Step 1, determine the mission objectives and intended use of the product. Step 2, establish and specify the performance parameters and allowable limits of the product. Step 3, determine the structural and functional limits of the product. Step 4, determine the conditions that constitute mission failure. Step 5, determine the work use model.
The terms used for product components in the mission reliability model should be consistent with those used in the basic reliability model. The mission reliability model should include reliability block diagrams and related mathematical models. The mission reliability model should be able to describe the intended use of each component of the product in the mission. Components intended for redundant work should be reflected in the model as parallel structures or other structures applicable to the mission phase and mission scope. 4.3 Methods of establishing models
The methods of establishing models include ordinary probability method, Boolean truth table method, logic diagram (i.e., non-intersection) method and Lante Carlo simulation method. Model establishment methods are used in situations where products are decomposed into components. 5 Reliability Prediction Methods
5.1 Categories
Reliability prediction is classified as follows:
Class I: Feasibility Prediction
Class II: Preliminary Prediction
Class III: Detailed Prediction
5.1.1 Feasibility Prediction (Class I)
GB 7827-87
Feasibility prediction is used in the product solution demonstration stage. In this stage, the level of detail of the design information is generally limited to describing the overall situation of the product. Detailed structural information is generally limited to information derived from existing products with functions and working requirements similar to the developed product.
5.1.2 Preliminary Prediction (Class II)
Preliminary prediction is used in the early stage of detailed design. In this stage, the written design structure information is engineering drawings and preliminary sketches. The level of detail of the available information can reach the components of the product, and there is no available stress analysis information. 5.1.3 Detailed prediction (Class III)
Detailed prediction is specified for use during and after the detailed design stage. The characteristic of this stage is that each component of the product needs to have working environment and stress information.
5.2 Methods
Reliability prediction methods include similar product method, similar circuit method, active component method, parts counting method and component stress analysis method. The first three methods are commonly used for Class I prediction, the fourth method is used for Class II prediction, and the last method is used for Class III prediction. Additional notes:
This standard was proposed by the Ministry of Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Reliability and Maintainability of Electrical and Electronic Products. The main drafters of this standard are Su Deqing, Shi Dinghua and Liao Mensheng. 246
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