Some standard content:
National Standard of the People's Republic of China
Reliability test for electronic measuring instrumente
1 Subject content and scope of application
1.1 Subject content
GB 11463-89
This standard specifies the basic requirements and test methods for reliability test of electronic measuring instrument (hereinafter referred to as product). 1.2 Scope of application
This standard is applicable to the reliability test of products whose failure law obeys exponential distribution. 2 Referenced standards
GB 2422 Basic environmental test procedures for electrical and electronic products Environmental test terms GB3187 Basic terms and definitions GB6587.1 General requirements for environmental test of electronic measuring instrument GB5060. General requirements for reliability test
3 Terms and symbols
Terms and definitions not defined in this standard shall be in accordance with the provisions of GB2422 and GB3187. 3.1 The lower limit of the assumed value of the mean trouble-free working time m When the true value of the mean trouble-free working time of the product is close to the assumed value, the standard test plan will reject the product with a high probability. 3.2 The upper limit of the assumed value of the mean trouble-free working time m When the true value of the mean trouble-free working time of the product is close to the assumed value, the standard test plan will accept the product with a high probability. 3.3 The confidence interval of the verified value of the mean trouble-free working time is the possible range of the true value of the mean trouble-free working time of the product under the specified confidence level and test conditions. 3.4 The observed value of the mean trouble-free working time of the product under the specified test conditions, which is equal to the cumulative and relevant test time of the tested product divided by the number of related failures.
3.5 The predicted value of the mean trouble-free working time m The predicted mean trouble-free working time determined by the reliability prediction method based on the structure and usage of the product. 3.6 User risk rate 3
When the true value of the mean trouble-free working time of the product is equal to the lower limit value m of its assumed mean trouble-free working time, the probability that the product is judged as acceptable by the test plan.
3.7 Producer risk rate
When the true value of the mean trouble-free working time of the product is equal to the upper limit value m of its assumed mean trouble-free working time, the probability that the product is judged as acceptable by the test plan.
Approved by the Ministry of Machinery and Electronics Industry of the People's Republic of China on March 31, 1989 and implemented on January 1, 1991
3.8 Identification ratio
GB 1146389
The ratio of the upper limit value (m.) of the assumed mean trouble-free working time to its lower limit (ml), that is, D=3.9 Related failure number r
After the reliability test, the number of failures that must be counted when the observed value of the mean trouble-free working time of the batch of products is calculated. 3.10 Test time
The cumulative trouble-free working time of the sample under the variable test state. Once a certain sample fails, the statistics of the relevant test time of the sample will be interrupted. After the failure is eliminated and the test is restarted, the calculation will be resumed. 3.11 Cumulative relevant test time T
The sum of the relevant test time of all tested products (cumulative test negative hours) (1)
Where, the relevant test time of the first sample, hn—sample size.
4 Reliability test types and test plans
4.1 Reliability test types
4.1.1 Reliability determination test
A test to determine the reliability characteristic value of the product. 4.1.2 Reliability verification test
A test to verify whether the reliability characteristic value of the product meets the specified reliability requirements. 4.1.2.1 Reliability identification test
Reliability identification test is applicable to;
#. Design finalization;
b. Production finalization
c: Appraisal after changes in design, process, raw materials, components, etc. The test results should be used as one of the bases for determining whether the product can be finalized, changed, etc. 4.1.2.2 Reliability acceptance test
Reliability acceptance test is applicable to: Check whether the products produced in batches can meet the reliability requirements. The test results should be used as one of the bases for determining whether the batch of products can be delivered for use.
4.1.3 On-site reliability test
Reliability verification or measurement test conducted under on-site use conditions. On-site tests can provide more realistic test results, and only require less test facilities and test costs. However, on-site tests cannot be conducted under controlled conditions, and the reproducibility of on-site tests is not as good as that of laboratory tests. Whether to use on-site reliability tests as reliability verification tests or as its supplementary tests is determined by the manufacturer and the user in terms of test conditions and test requirements. 4.2 Test scheme
4.2.1 Fixed time constant number truncation test scheme
The time constant number truncation test scheme recommended by this standard is shown in Table 1. Scheme number
4-2.2 Sequential test scheme
GB11463-89
Table 1 Fixed time constant number load development test scheme
Characteristics of the scheme
Specified risk rate, %
The sequential test scheme recommended by this standard is shown in Table 2. Scheme number
Discrimination ratio
Table 2 Sequential test scheme
Characteristics of the scheme
Specified risk rate, %
-Moving situation, select scheme numbers 2-1, 2-2 and 2-3, and the tables and figures of the test method are shown in Appendix A (Supplement). 4.3 Selection of test scheme
Truncation time
(number of me books)
Integer ratio
Drum tail failure
Time to make a judgment
(times
The test scheme for reliability identification test and acceptance test of products can be selected from Table 1 and Table 2. The selection principle is: a. When it is required to estimate and verify the true value of the mean trouble-free working time of the product through the test, it is recommended to use the fixed-time constant tail test scheme.
For reliability identification test, technical standards recommend the use of fixed-time constant tail test scheme. b. When it is only necessary to make an acceptance or rejection judgment on the mean trouble-free working time of the product based on a predetermined judgment risk rate (n.3) and discrimination ratio (D,), and it is not necessary to determine the total test time and funds before the test, it can be selected The same sequential test plan. For the reliability acceptance test of the product, this standard recommends the use of a sequential test plan. The guidance for selecting the type of test plan is shown in GB5080.1. 5 Test requirements
5.1 Reliability prediction
Before the reliability identification test, a product reliability prediction should be carried out, and the product's half mean failure time prediction value should be close to or greater than the theoretical value. To ensure that the reliability test plan accepts the product with a high probability. 5.2 Pretreatment
Before the test, the test column shall not be subjected to aging and other pretreatment that is different from the products delivered for use. Before the test, the product is allowed to undergo preventive maintenance and treatment consistent with field use. 5.3 Determination of test samples
5.3.1 The test samples shall be randomly selected from the products that have passed the characteristic inspection. 5.3.2 The sample composition of the reliability identification shall not be less than 2% of GB 11463-89
5.3.3 The sample of reliability acceptance test is generally drawn according to the batch size of the product. The recommended sample size is shown in Table 3. Table 3 Reliability acceptance test sample
Sample size
17--52
97~200
220 and above
5.4 Test time
Size of sample
10% of the whole teaching
5.4.1 The expected test time is the selected truncation time divided by the sample size when the fixed-time constant number truncation test plan is adopted. When the sequential test is adopted, it is the maximum cumulative relevant test time of the selected plan divided by the sample size. When calculating, mr=Dmm. The value of m1 is the lower limit of MTBF given in the product standard. 5.4.2 When a fixed-time constant-number truncation test scheme is adopted, the test is terminated when the test reaches the truncation test time or the number of truncation-related failures. 5.4.3 When a sequential test scheme is adopted, if a judgment can be made within the maximum cumulative relevant test time, the test is terminated. When the test reaches the maximum cumulative relevant test time, the test must be terminated, and a judgment is made on the entire test according to the judgment standard. 5.5 Test preparation
5.5.1 Inspection and test of functions and performance
Before the reliability test, the sample should be inspected and tested for its functions and (or) performance characteristics in accordance with the requirements of the product standard, and the inspection results should be recorded in detail for reference.
5. 5.2 Requirements for test equipment, instruments and meters The test equipment should be able to meet the test requirements, and the test instruments and meters used should comply with the specified measurement cycle. 5.5.3. Formulate the implementation plan for reliability test. Before the test, the implementation plan for reliability test should be formulated. Its contents should include: a. Product model and name: Product reliability index: Selection of reliability test plan: Determination of sample size: Provision of main failure criteria: Requirements for test equipment and test instruments Arrangement of test time and provisions of detection time; h. Formulate the plan and the opinions signed by the municipal approval personnel. 6 Test stress and timing: 6.1 Test stress: 1. The application of test stress of group II instruments should be selected according to Table 4. For group II instruments, the stress types listed in Table 4 should be determined in the product standard and agreed upon by the manufacturer and the user.
Stress type
Environmental group
, Group I
Cheek rate cycle range, grip amplitude, sweep
Frequency rate is in accordance with the requirements of Group I and Group I in GB 6587.1
.
Cycle 2 times on the vertical plane.
Non-working state
According to GB B587.1I group perturbation
6.2 Test timing diagram
GB 11463—89
Table 4 Test stress type
Electrical stress
Power on and off cycle,/16 voltage cycle; within each 24h, 1/3
time voltage is 196V
1/3||time voltage is 220V
1/3||time positive voltage is 242V
Power on and off cycle, voltage cycle
1/2 time is 220V
1/4 time is 198V
1/4 time is 243V
, 1 group of instrument test timing diagram shall be carried out according to Figure 1. 6.2.1
High temperature stress shall be in accordance with the upper limit of the working range of Group I and Group II in GB 6587.1 respectively. Low humidity: -1℃+2℃
Storage for 4h
High temperature +502℃
Test for 4h
90%～95%RH
Storage for 4b
Test for 2h
The test sequence of Group I instruments shall be specified in the product standard or agreed upon by the manufacturer and user, and shall reproduce the typical working conditions and environmental stresses occurring in use as closely as possible. Chengli
Shangyang temperature
Performance chicken skin
Kinetic energy inspection
Figure 1 Test timing diagram
6.2.3 In the test, power on for 7h and power off for 1h is a working cycle. In each working cycle, the panel function is checked twice. The function inspection items and methods are specified in the product standard.
6.2.4 For battery-powered products, the battery voltage is reduced from the full state to the lower limit of the battery charge as a voltage cycle. 6.2.5 In the test, the performance characteristics shall be tested in accordance with the provisions of the product standard. After the vibration test and in every 1/3 of the scheduled test time, at least one test shall be carried out. The power supply voltage during the test is 198V, 220V.242V respectively. The sequential test must be tested once before the general (acceptance).
GB11463-89
6.2.6 The cumulative relevant test time of each sample shall not be less than half of the average power-on time of all samples. 6.2.7 Within each 21-hour test cycle, for samples with multi-function modes, each function mode shall be tested alternately. 7 Failure and failure criteria
7.1 Failure
Failure means that the product cannot complete its specified function under specified conditions and within specified time: its performance characteristics exceed the limits specified in the product standard.
7.1.1 Independent failure
refers to failure caused by the sample itself, generally including: component failure
failure caused by defects in the component itself.
b. Product design failure
failure caused by defects in product design. Product manufacturing failure
failure caused by improper product manufacturing process or poor quality of production process. d. Software error
Effect caused by program errors of microcomputers or microprocessors. e. Failure of the regulating mechanism
Failure caused by defects in the regulating and controlling mechanism of the product itself, resulting in the product being unable to complete the specified functions. f. Failure of the built-in test system
Failure caused by defects in the built-in test system, resulting in the product performance characteristics not being able to be maintained between the specified upper and lower limits. g. Repeated failure
In the same or equivalent use, the same component fails twice or more due to the same basic failure mechanism. h. Intermittent spike effect
Failure in which the product automatically recovers its function within a certain period of time without repair after failure. 1. Failure caused by operation and maintenance procedures
Failure caused by improper operation, maintenance, and repair procedures provided by the manufacturer. 7.1.2 Dependent spike effect
Failure caused by direct or indirect failure of other failures in the sample, or failure caused by failure of test equipment, instruments, meters, etc.
a. Misuse failure
Failure caused by applying stress exceeding the specified stress level to the specimen, improper installation and excessive testing of the operator.
b. Failure of the party's responsibility
Failure caused by the equipment, operation, maintenance and repair procedures provided by the user of the tester. . Failure caused by components with a limited life
Failure caused by components with a specified life span that have been in use for more than the specified replacement period but have not been replaced. 7.1.3 Unconfirmed failure
: Failure that has not been identified as the cause of the failure, has not recurred during the test, or is still under investigation at the end of the test. 7.1.4 Failure that leads to an immediate rejection decision will cause dangerous or unsafe failures to the test, use and maintenance personnel, or cause a large number of materials to be damaged. 7.2 Failure judgment
7.2.1 Judgment criteria
GB11463-89
During the test, relevant and non-related judgments should be made for the spikes that appear. 7.2.1.1 Related failures:
refers to all independent failures caused by the product's own conditions and expected to occur in the field (generally refers to the various failures described in Article 7.1.1 of this standard). When interpreting the test results or calculating the reliability characteristic value, the number of related failures must be counted. 7.2.1.2 Non-related failures
Failures that are not caused by the product's own conditions and are not expected to occur in the field (generally refers to the various failures violated in Article 7.1.2 of this standard). When analyzing the test results or calculating the reliability characteristic value, all non-related failures are not counted in the number of failures. 7.2.2 Failure judgments that require special provisions: For the failure of the internal fuse of the product. Special provisions should be made. If only one such failure occurs during the test, it can be considered as a non-correlated failure. If it occurs twice or more and it cannot be confirmed that it is a dependent failure, it should be counted as a related failure. b. When repeated failures occur during the test, each failure should be counted in the number of failures. After analyzing the cause, the test should be continued without taking necessary measures. The test time should be longer than the time when the repeated failure first occurred until such failures no longer occur during the test. In this case, no matter how many repeated failures occur, only one non-correlated failure should be counted. Otherwise, no matter how many repeated failures occur, they should be counted in the number of related failures. c. For unconfirmed failures or intermittent failures, if it cannot be confirmed that they are non-correlated failures, they should be judged as related failures. :7.3 Judgment of failure time
If it is not possible to make an accurate judgment on the time when the failure occurs, it is judged that the failure occurred at the time of the last observation and inspection. 7.4 Treatment of sharp failure
7.4.1 When failure occurs during the test, the failure situation should be recorded truthfully and in detail, and the failed sample should be withdrawn from the test for inspection. 7.4.2 Before overhauling failed samples, the following measures should be taken: a. Allow necessary simulation tests or supplementary tests to confirm failures; b. Predict and check possible failures to eliminate them at the same time; c. Preliminary estimate of failure categories; 7.4.3 During the troubleshooting of failed samples, the following provisions should be followed: a. Allow adjustments to the relevant adjustment parts that caused the failures, but the irrelevant parts should not be changed at will; b. All components that have been confirmed to be failed should be replaced. However, any component whose performance has degraded but has not exceeded the rated value should not be replaced unless it can be proved that the stress experienced by the degraded component exceeds the allowable rated value due to the failure of other components. The replaced components with degraded performance should not be reinstalled in the product; c.The replaced failed components shall be registered and kept as they are, in order to prepare for detailed failure analysis: d. If the replaced components cannot eliminate the failure and the original components have not been confirmed to be failed, the original components shall be replaced; the repairable components and whole parts in the sample shall not be replaced, otherwise, each replacement shall be counted as a related failure: e.
1. Although the sample has signs of failure, but has not been judged as a failure, the ongoing test shall not be interrupted to take repair measures, otherwise, each repair action taken shall be counted as a related failure; g. For the failures found during the troubleshooting process, if it cannot be determined that they are non-related failures, they shall be counted as related failures! h. After the fault is repaired, necessary confirmation of the repair effect shall be carried out. Failures that occur during this period can be regarded as non-related failures, and the time of the confirmation test shall not be counted as relevant test time: 1. It is allowed to replace components that have been used to their expected life but have not shown failure or have been confirmed to be failed according to the maintenance system, and carry out necessary inspections and adjustments related to the replacement. For components and parts that have degraded performance but have not yet reached the end of their service life, cannot be confirmed to be failed, and have no special provisions for maintenance, they shall not be replaced preventively at will. Otherwise, each replacement shall be counted as a related failure. Failures caused by inspection shall not be counted in the test results, but shall be recorded and analyzed. 8 Acceptance and Rejection Judgment
B.1 Acceptance
GB 11463-89
If there is no failure that leads to rejection and the test results meet the acceptance judgment criteria, the trial product or product represented by the sample shall pass the reliability appraisal or acceptance. 8.2 Rejection
If the sample of the test is unacceptable, the trial product represented by the sample shall be submitted for design finalization or production finalization appraisal, and the reliability design shall be re-performed. The batch of products represented by the sample of the acceptance test shall be rejected. 8.3 Corrective measures
83.1 For the batch of products received, the manufacturer shall analyze all failures that occurred during the test and take corresponding corrective measures. 8.3.2 When the batch of products is judged to be rejected, the manufacturer shall formulate a corrective action plan. 8.3.3 Changing the performance or reliability indicators of the product shall not be considered as a corrective measure. 9 Test data processing
9.1 Estimation of the observed value of the mean trouble-free time (m) Divide the cumulative test time T by the cumulative number of related failures r, that is: AT
9.2 Estimation of the confidence interval of the mean trouble-free working time (m) In order to obtain the interval estimate of the verification value of the mean trouble-free working time, the interval estimate used must be specified. 9.2.1 When the test makes a acceptance decision, the estimation method of the confidence interval of the mean trouble-free working time (m) is as follows: Estimate the observed value of the mean trouble-free working time (m) according to 9.1.||t t||b, according to the corresponding cumulative related failure number, change the specified confidence level to read the corresponding lower limit factor and upper limit factor from Table 5, (2)
month lower limit factor and upper limit factor are multiplied by the observed value of the average unexplained working time (m), and the lower limit value (mL) and upper limit value (mu) of the confidence interval of the mean trouble-free working time (m) are obtained. d. Fill in the calculation results of the working surface according to the following formula: 研=××%(L,m
where: ××%……- represents the confidence level of the interval estimate. e. For the numbers not listed in Table 6, the following formula is used to calculate: MTRF The lower limit factor of
The upper limit factor of MTBF
Where: r—Number of nested related failures:
c——Interval estimation confidence level
X\一X, the lower quantile value of the distribution.
(3)
9.2.2. If the test is rejected and an interval estimate is required, the estimation method is the same as Article 9.2.1, where the table is changed to Table 6. For the calculation of the teaching values not listed in Table 6, the lower limit factor is calculated using formula (4), and the degree of freedom 2°+2 in formula (4) is changed to 2. The upper limit factor is still calculated using formula (5).
GB11463---89
9.2.3 One-sided interval estimation of average trouble-free working time When the test makes an acceptance decision, the average unexcused working time The unilateral lower limit value (mL) is equal to the lower limit factor multiplied by the plan value (m). The lower limit factor of MTBF =
x\(c,2r—2)
m(c,2r+2)
If the test makes a rejection decision and it is necessary to calculate the unilateral lower limit value (m) of the average unexcused seat working time, change the white in formula (8) and 9) from 2r+2 to 2r for calculation,
Table 5 Confidence limit factors of MTBF verification value (used when accepting) Set
Accumulated number of related failures
0% lower limit
10 Reliability test report and record
70% upper limit
60% upper limit
10.1 Reliability test report
The test report should provide reliable data for the final judgment of the test results. The content should include: *, product model, name and manufacturer, h. selected test plan and test stress, 90% lower limit, 0% upper limit, GB 1146389, failure types and treatments during the test, c. d. test data treatment, final conclusion of the test and recommended measures, e. f. person responsible for the test. The format is shown in Table B1 in Appendix B (reference).
Table 6 Confidence limit factors for NTBF verification value (for rejection) Confidence interval probability
Cumulative number of related failures
70% lower limit
70% upper limit
10.2 Failure analysis report for reliability test
80% lower limit
80% upper limit
s0% lower limit
90%. Upper limit
Each failure should have a report. The content of the report includes the description of the failure and the judgment of the failure, the analysis and correction of the failure, and the opinions signed by the test operator, maintenance personnel, test supervisor and technical supervisor on the failure handling. The format is shown in Appendix B (reference document) Table B2.
10.3 Test records
The test and operation conditions should be recorded in detail. The test records include reliability test logs, function and performance characteristics test records, and the format is shown in Appendix (reference document) Table R3 and Table B4. A1 Timing fixed number truncation test plan
GB 11463-89
Appendix A
Test method range
(supplement)
Test plan 1-1 Working characteristic curve
Test plan 1-2 Working characteristic curve
Actual state·
Actual
A2 Sequential test plan
GB11463-89
Figure A3 Test plan 13 Working characteristic curve
Net=x, time, maximum time fixed point
10 Use, chlorine accumulation index test
Figure A4 Test plan 2-13 Changes to the performance or reliability indicators of the product are not considered corrective measures. 9 Test data processing
9.1 Estimation of the observed value of the mean trouble-free time (m) Divide the cumulative test time T by the cumulative number of related failures r, that is: AT
9.2 Estimation of the confidence interval of the mean trouble-free working time (m) In order to obtain the interval estimate of the verification value of the mean trouble-free working time, the interval estimate used must be specified. 9.2.1 When the test makes a decision, the estimation method of the confidence interval of the mean trouble-free working time (m) is as follows: Estimate the observed value of the mean trouble-free working time (m) according to 9.1. ||t t||b, according to the corresponding cumulative related failure number, change the specified confidence level to read the corresponding lower limit factor and upper limit factor from Table 5, (2)
month lower limit factor and upper limit factor are multiplied by the observed value of the average unexplained working time (m), and the lower limit value (mL) and upper limit value (mu) of the confidence interval of the mean trouble-free working time (m) are obtained. d. Fill in the calculation results of the working surface according to the following formula: 研=××%(L,m
where: ××%……- represents the confidence level of the interval estimate. e. For the numbers not listed in Table 6, the following formula is used to calculate: MTRF The lower limit factor of
The upper limit factor of MTBF
Where: r—Number of nested related failures:
c——Interval estimation confidence level
X\一X, the lower quantile value of the distribution.
(3)
9.2.2. If the test is rejected and an interval estimate is required, the estimation method is the same as Article 9.2.1, where the table is changed to Table 6. For the calculation of the teaching values not listed in Table 6, the lower limit factor is calculated using formula (4), and the degree of freedom 2°+2 in formula (4) is changed to 2. The upper limit factor is still calculated using formula (5).
GB11463---89
9.2.3 One-sided interval estimation of average trouble-free working time When the test makes an acceptance decision, the average unexcused working time The unilateral lower limit value (mL) is equal to the lower limit factor multiplied by the plan value (m). The lower limit factor of MTBF =
x\(c,2r—2)
m(c,2r+2)
If the test makes a rejection decision and it is necessary to calculate the unilateral lower limit value (m) of the average unexcused seat working time, change the white in formula (8) and 9) from 2r+2 to 2r for calculation,
Table 5 Confidence limit factors of MTBF verification value (used when accepting) Set
Accumulated number of related failures
0% lower limit
10 Reliability test report and record
70% upper limit
60% upper limit
10.1 Reliability test report
The test report should provide reliable data for the final judgment of the test results. The content should include: *, product model, name and manufacturer, h. selected test plan and test stress, 90% lower limit, 0% upper limit, GB 1146389, failure types and treatments during the test, c. d. test data treatment, final conclusion of the test and recommended measures, e. f. person responsible for the test. The format is shown in Table B1 in Appendix B (reference).
Table 6 Confidence limit factors for NTBF verification value (for rejection) Confidence interval probability
Cumulative number of related failures
70% lower limit
70% upper limit
10.2 Failure analysis report for reliability test
80% lower limit
80% upper limit
s0% lower limit
90%. Upper limit
Each failure should have a report. The content of the report includes the description of the failure and the judgment of the failure, the analysis and correction of the failure, and the opinions signed by the test operator, maintenance personnel, test supervisor and technical supervisor on the failure handling. The format is shown in Appendix B (reference document) Table B2.
10.3 Test records
The test and operation conditions should be recorded in detail. The test records include reliability test logs, function and performance characteristics test records, and the format is shown in Appendix (reference document) Table R3 and Table B4. A1 Timing fixed number truncation test plan
GB 11463-89
Appendix A
Test method range
(supplement)
Test plan 1-1 Working characteristic curve
Test plan 1-2 Working characteristic curve
Actual state·
Actual
A2 Sequential test plan
GB11463-89
Figure A3 Test plan 13 Working characteristic curve
Net=x, time, maximum time fixed point
10 Use, chlorine accumulation index test
Figure A4 Test plan 2-13 Changes to the performance or reliability indicators of the product are not considered corrective measures. 9 Test data processing
9.1 Estimation of the observed value of the mean trouble-free time (m) Divide the cumulative test time T by the cumulative number of related failures r, that is: AT
9.2 Estimation of the confidence interval of the mean trouble-free working time (m) In order to obtain the interval estimate of the verification value of the mean trouble-free working time, the interval estimate used must be specified. 9.2.1 When the test makes a decision, the estimation method of the confidence interval of the mean trouble-free working time (m) is as follows: Estimate the observed value of the mean trouble-free working time (m) according to 9.1. ||t t||b, according to the corresponding cumulative related failure number, change the specified confidence level to read the corresponding lower limit factor and upper limit factor from Table 5, (2)
month lower limit factor and upper limit factor are multiplied by the observed value of the average unexplained working time (m), and the lower limit value (mL) and upper limit value (mu) of the confidence interval of the mean trouble-free working time (m) are obtained. d. Fill in the calculation results of the working surface according to the following formula: 研=××%(L,m
where: ××%……- represents the confidence level of the interval estimate. e. For the numbers not listed in Table 6, the following formula is used to calculate: MTRF The lower limit factor of
The upper limit factor of MTBF
Where: r—Number of nested related failures:
c——Interval estimation confidence level
X\一X, the lower quantile value of the distribution.
(3)
9.2.2. If the test is rejected and an interval estimate is required, the estimation method is the same as Article 9.2.1, where the table is changed to Table 6. For the calculation of the teaching values not listed in Table 6, the lower limit factor is calculated using formula (4), and the degree of freedom 2°+2 in formula (4) is changed to 2. The upper limit factor is still calculated using formula (5).
GB11463---89
9.2.3 One-sided interval estimation of average trouble-free working time When the test makes an acceptance decision, the average unexcused working time The unilateral lower limit value (mL) is equal to the lower limit factor multiplied by the plan value (m). The lower limit factor of MTBF =
x\(c,2r—2)
m(c,2r+2)
If the test makes a rejection decision and it is necessary to calculate the unilateral lower limit value (m) of the average unexcused seat working time, change the white in formula (8) and 9) from 2r+2 to 2r for calculation,
Table 5 Confidence limit factors of MTBF verification value (used when accepting) Set
Accumulated number of related failures
0% lower limit
10 Reliability test report and record
70% upper limit
60% upper limit
10.1 Reliability test report
The test report should provide reliable data for the final judgment of the test results. The content should include: *, product model, name and manufacturer, h. selected test plan and test stress, 90% lower limit, 0% upper limit, GB 1146389, failure types and treatments during the test, c. d. test data treatment, final conclusion of the test and recommended measures, e. f. person responsible for the test. The format is shown in Table B1 in Appendix B (reference).
Table 6 Confidence limit factors for NTBF verification value (for rejection) Confidence interval probability
Cumulative number of related failures
70% lower limit
70% upper limit
10.2 Failure analysis report for reliability test
80% lower limit
80% upper limit
s0% lower limit
90%. Upper limit
Each failure should have a report. The content of the report includes the description of the failure and the judgment of the failure, the analysis and correction of the failure, and the opinions signed by the test operator, maintenance personnel, test supervisor and technical supervisor on the failure handling. The format is shown in Appendix B (reference document) Table B2.
10.3 Test records
The test and operation conditions should be recorded in detail. The test records include reliability test logs, function and performance characteristics test records, and the format is shown in Appendix (reference document) Table R3 and Table B4. A1 Timing fixed number truncation test plan
GB 11463-89
Appendix A
Test method range
(supplement)
Test plan 1-1 Working characteristic curve
Test plan 1-2 Working characteristic curve
Actual state·
Actual
A2 Sequential test plan
GB11463-89
Figure A3 Test plan 13 Working characteristic curve
Net=x, time, maximum time fixed point
10 Use, chlorine accumulation index test
Figure A4 Test plan 2-1
Each failure should have a report. The content of the report includes the description of the failure and the judgment of the failure, the analysis and correction of the failure, and the opinions of the test operator, maintenance personnel, test leader and technical leader on the failure handling. The format is shown in Appendix B (reference document) Table B2.
10.3 Test records
The test and operation conditions should be recorded in detail. The test records include reliability test logs, function and performance characteristics test records, and the format is shown in Appendix (reference document) Table R3 and Table B4. A1 Timing fixed number truncation test plan
GB 11463-89
Appendix A
Test method range
(supplement)
Test plan 1-1 Working characteristic curve
Test plan 1-2 Working characteristic curve
Actual state·
Actual
A2 Sequential test planwww.bzxz.net
GB11463-89
Figure A3 Test plan 13 Working characteristic curve
Net=x, time, maximum time fixed point
10 Use, chlorine accumulation index test
Figure A4 Test plan 2-1
Each failure should have a report. The content of the report includes the description of the failure and the judgment of the failure, the analysis and correction of the failure, and the opinions of the test operator, maintenance personnel, test leader and technical leader on the failure handling. The format is shown in Appendix B (reference document) Table B2.
10.3 Test records
The test and operation conditions should be recorded in detail. The test records include reliability test logs, function and performance characteristics test records, and the format is shown in Appendix (reference document) Table R3 and Table B4. A1 Timing fixed number truncation test plan
GB 11463-89
Appendix A
Test method range
(supplement)
Test plan 1-1 Working characteristic curve
Test plan 1-2 Working characteristic curve
Actual state·
Actual
A2 Sequential test plan
GB11463-89
Figure A3 Test plan 13 Working characteristic curve
Net=x, time, maximum time fixed point
10 Use, chlorine accumulation index test
Figure A4 Test plan 2-1
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