1、ANSI/LEC/ASQ D61123-1997 Reliability testing - compliance plans for success ratio Approved as an American National Standard by: American Society for Quality ANSI/IEC/ASQ D61123-1997 MERICAN Approved as an American National Standard by: American Society for Quality An American National Standard Appro
2、ved on September 16, 1997 American National Standards: An American National Standard implies a consensus of those substantially concerned with its scope and provisions. An American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general public. The existence o
3、f an American National Standard does not in any respect preclude anyone, whether he or she has approved the standard or not, from manufacturing, purchasing, or using products, processes, or procedures not conforming to the standard. American National Standards are subject to periodic review and user
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7、d in the document, the term “International Standard” refers to the American National Standard adoption of this and other International Standards. ASQ Mission: To facilitate continuous improvement and increase customer satisfac- tion by identifying, communicating, and promoting the use of quality pri
8、nciples, cori- cepts, and technologies; and thereby be recognized throughout the world as the leading authority on, and champion for, quality. 1098 765432 1 Printed in the United States of America Printed on acid-free paper Published by: American Society for Quality Quality Press 61 1 East Wisconsin
9、 Avenue Milwaukee, Wisconsin 53201 -3005 800-248-1 946 Web site http:/www.asq.org I/IEC/ASQ D61123-1997 Contents Page Foreword . I Clause 1 2 3 4 5 6 7 8 9 10 Scope . 2 Normative references . 2 Other references Definitions List of symbols . Application . 6.1 Reliability requirement. . 6.2 Repair and
10、 replacement 6.3 Types of test plans 6.4 General test procedure General decision criteria . e . 3 4 . 4 . 4 . 4 . 5 . 5 Truncated sequential test plans . 5 8.1 Characteristics . 5 . 8.4 Expected number of trials to decision . Fixed trial/failure terminated test plans . 10 9.1 Characteristics . 10 9.
11、2 Decision criteria, . 1 O Design of trial or failure terminated test plans . 12 10.1 Characteristics . . 12 10.2 Approach . 12 10.3 Common 10.4 Other cases 10.5 Examples of 13 10.6 Procedur 10.7 Decision . ANSI/IEC/ASQ D61123-1997 Annexes A Additional information on sequential test plans . 23 6 Des
12、ign of trial or failure terminated test plans-Examples . 25 C Design of trial or failure terminated test plans-Mathematical procedures and formulas., 27 iv I/IEC/ASQ D6i 123-1999 ILITY TES Compliance test plans for s rati Foreword 1) The formal decisions or agreements of the IEC on technical matters
13、, prepared by Technical Committees on which all the National Committees having a special interest therein are represented, express, as nearly as possible, an international consensus of opinion on the subjects dealt with. 2) They have the form of recommendations for international use and they are acc
14、epted by the National Committees in that sense. 3) In order to promote international unification, the IEC expresses the wish that all National Committees should adopt the test of the IEC recommendation for their national rules in so far as national condi- tions will permit. Any divergence between th
15、e IEC recommendation and the corresponding national rules should, as far as possible, be clearly indicated in the latter. This International Standard IEC 1123 has been prepared by IEC Technical Committee No. 56: Dependability. This International Standard replaces IEC 605-5 (1982) including Amendment
16、 1 (1987). The text of this standard is based on IEC 605-5, first edition, including Amendment No. 1 and the fol- lowing documents: 56( CO) 1 44 56( CO) 1 52 Full information on the voting for the approval of this standard can be found in the Voting Report indi- cated in the above table. Annexes A,
17、B and C are for information only. 1 ANSI/IEC/ASQ D61123-I997 Re1 ia bi lity Testing Compliance test plans for success ratio 1 Scope This International Standard specifies procedures for applying and preparing compliance test plans for success ratio or failure ratio. The procedures are based on the as
18、sumption that each trial is statistically independent. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subje
19、ct to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and IS0 maintain registers of currently valid International Standards. I EC 60050( 191 ): 19
20、90, International Electrotechnical Vocabulary-Chapter 79 1: Dependability and quality of service. IEC 60605-1 : 1978, Equipment reliability testing-Part 7: General requirements. Amendment 1 (1C382). 3 Other references IEC 6041 O: 1973, Sampling plans and procedures for inspection by attributes. IS0
21、3534: 1977, Statistics-Vocabulary and symbols. 4 Definitions Terms and definitions are in accordance with IEC 60050(191). In addition, the following definitions are applicable for this International Standard: 4.1 success ratio: The probability that an item will perform a required function or that a
22、trial will be successful under stated conditions. NOTE-An observed success ratio is the ratio of the number of non-faulty items or of successful trials at the completion of testing, to the total number of test items or number of trials. 2 C/ASQ D61123-19 4.2 failure ratio: The probability that an it
23、em will fail or that a trial will be unsuccessful under stated conditions. NOTE-An observed failure ratio is the ratio of the number of faulty items or of unsuccessful trials at the completion of test- ing, to the total number of test items or number of trials. 5 List of symbols a a C D D h n nf n,
24、*t P Po P1 Pa 4 nominal producers risk (type I risk) true producers risk (type I risk) nominal consumers risk (type II risk) true consumers risk (type II risk) acceptable number of failures or unsuccessful events during the test NOTE-r, number of failures for rejection in IEC 605-5, first edition (1
25、982), corresponds to c + 1. nominal discrimination ratio, D = p1 / po = (1 - 9,) / (1 - qo) NOTE-, is the corresponding symbol in IEC 605-5, first edition (1982). true discrimination ratio intercept values of the accept and reject lines on the vertical axis of the sequential test diagram (see figure
26、 1) number of items, number of trials, number of events, sample size number of items, number of trials, number of events, sample size required for acceptance accumulated number of trials in a sequential test plan number of items, number of trials, number of events, sample size at truncation true fai
27、lure ratio, p = 1 - q specified acceptable failure ratio, corresponding to acceptable quality level (AQL) unacceptable failure ratio, corresponding to limiting quality (LQ) probability of acceptance true success ratio, q = 1 - p NOTE-Ris the corresponding symbol in IEC 605-5, first edition (1982). A
28、NSI/IEC/ASQ D61123-I997 go specified acceptable success ratio, go = 1 - po g, unacceptable success ratio, g, = 1 - pl r number of relevant failures or relevant unsuccessful events r, number of relevant failures or relevant unsuccessful events at truncation s slope of accept and reject lines in the s
29、equential test diagram (see figure 1) 6 Application 6.1 Reliability requirement The requirement is assumed to be specified as: - acceptable failure ratio, po or - acceptable success ratio, 40 (PO = 1 - go). These test plans are based on the assumption that each trial is statistically independent and
30、 that the probability of success (or failure) is constant, .e. the binomial distribution assumptions apply. The true producers and consumers risks for the test plans differ from the nominal characteristics a and due to the necessary approximations to whole numbers and to the truncation of the sequen
31、tial tests. 6.2 Repair and replacement The test plans given in this standard are applicable to reused as well as non-reused (one-shot) teins. Reused items may be repaired between successive trials, provided that the state and performance are the same at the start of all trials. For non-reused items,
32、 a separate test item is used for each trial. 6.3 Types of test plans Test plans are given for three types of tests: -truncated sequential tests (see clause 8); - fixed trial/failure terminated tests (see clause 9); - designed trial/failure terminated tests (see clause 1 O). The detailed reliability
33、 test specification shall state which type of test and which test plan are to be used. Guidance for the choice of type of test is similar to that given in IEC 605-1, 7.3.1, for truncated sequen- tial and time/failure terminated tests for the case in which the reliability measure is a function of tim
34、e. 4 6.4 General test procedure The test items shall be subjected to the number of trials according to the relevant test plan. For reused, replaced or repaired items, the detailed reliability test specifications should preferably state the number of test items as well as the maximum number of trials
35、 for each test item. A trial is defined as the operation or cycle as described in the detailed reliability test specification. eneral decision criteria All test plans and decision criteria are based on either: - an acceptable number of relevant failures for a specified number of trials; or - an acce
36、ptable number of trials for a specified number of relevant failures. The numbers of trials and relevant failures (see IEC 605-1, 9.2) are counted and compared with the deci- sion criteria of the test plan. The detailed decision criteria for the three types of test plans are given in 8.2, 9.2 and 10.
37、7, respectively. Truncated sequential test plans 8.1 Characteristics Sequential test plans are characterized by decision rules for accepting or rejecting compliance, or for continuing testing, after any number of trials. They are determined by selected values of risks and dis- crimination ratio. In
38、order to implement a test plan, go has to be specified (or derived). Associated operating characteristic curves and values of the expected relevant number of trials to deci- sion are included. Table 1 presents the appropriate test plans for various values of the specified qo, D, a and . The table co
39、ntains parameter values of h, s, n, and r, for each test plan (see figure 1). NOTE-The truncation affects the values of a and . However, the truncation values of table 1 are chosen so that the maximum values of a and are less than 0.055; 0.105; 0.205 and 0.305, for values of a and 0.05; 0.10; 0.20 a
40、nd 0.30 respectively. The truncation values were obtained from a computer program which calculated a and for increasing values of n, and r, until the maximum values were within the above stated bounds. .e Decision criteria The decision criteria are as follows: - accept if sn, - h r; - continue if sn
41、, - h sn, + h. ANSI/IEC/ASQ D61123-I997 1 .o 40 1 -s qi 0.0 The sequential test plans shall be truncated at lines based on the values given in table 1, The truncation gives rise to the following additional criteria: - accept if n = n, and r r,. The accumulated results are checked against the criteri
42、a after each trial and a decision is made whether to accept, continue or reject. pa 1 .o 1 -a 0.5 0.0 Figure 1-Truncated sequential test 8.3. Operating characteristic curve For any of the truncated sequential tests, the following approximate points on the operating characteristic curve are given: 6
43、WASQ D61123-1997 o 1.0 c m Q 0 o m I a l-a L O 0.0 91 l-s 90 1 .o True success ratio a Figure 2-OC curve .4. Expected number of trials to decision For any of the truncated sequential test plans, the following approximate points can be determined for the curve of the expected number of trials to deci
44、sion versus the true success ratio: ANSI/IEC/ASQ D61123-I997 Expected number of trials s(l - s) h(l - 2a) h - S h 1-s - 0.0 41 1 -s qo 1 .o True success ratio 4 Figure 3-Curve of expected number of trials Table I-Truncated sequential tests qo 0.9995 0.9990 0.995 0.990 0.980 0.970 0.960 0.950 0.940 0
45、.930 0.920 0.910 0.900 0.850 0.800 0 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.50 1.75 2.00 3.00 1.5
46、0 1.75 2.00 3.00 1.50 1.75 2.00 3.00 S 0.00062 0.00067 0.00072 0.00091 0.00125 0.00134 0.00144 0.00182 0.00617 0.00670 0.00722 0.0091 1 0.01233 0,01341 0.01444 0.01824 0.02467 0.02682 0.02889 0.03633 O ,0370 1 0.04085 0.04336 0.05493 0.04936 0.05369 0.05785 0.07330 0.06171 0.06714 0.07236 0.09103 0.
47、07407 0.09060 0.08699 0.11057 0.08643 0.09407 O. 1 O1 44 0.12930 0,09880 O. 10755 0.11602 0.14814 0.11117 O. 1 21 05 0.13062 0.16709 0.12355 O. 13456 O. 14524 O. 1861 7 o. 18555 0.20236 0.28379 0.24774 0.27063 0.29330 0.38685 0.21882 - h 7.2574 4.2449 2.6777 7.2529 5.2545 4.2418 2.6753 7.2171 5.2263
48、 4.2173 2.6557 7.1723 5.1910 4.1866 2.6313 7.0827 5.1204 4.1252 2.5822 6.9931 5.0498 4.0637 2.5329 6.9034 4.9791 4.0022 2.4835 6.8137 4.9083 3.9406 2.4337 6.7240 4.8375 3.8788 2.3838 6.6342 4.7666 3.8170 2.3336 6.5444 4.6956 3.7551 5.2580 2.2831 6.4546 4.6246 3.6931 2.2323 6.3647 4.5535 3.6309 2.181
49、2 5.9144 4.1968 3.3184 1.9195 5.4628 3.8376 3.0020 1.6433 =5% n, 307,850 57,176 17,223 102,220 47,667 28,536 97,383 8,609 20,038 9,269 1,540 9,803 4,530 2,634 767 4,713 2,169 1,263 374 3,015 1,389 817 2,220 1,017 589 170 1,721 78 1 455 133 1,419 636 366 103 1,177 533 303 86 1,008 455 264 74 88 1 395 234 64 772 343 204 54 457 204 115 31 304 137 78 17 5,458 228 - r1 122 60 38 14 121 60 38 14 119 59 37 13 117 58 36 13 113 56 35 13 1 o9 54 34 12 107 53 33 12 105 51 32 12 103 50 31 11 1 O0 49 30 11 98 48 30 11 86 47 30 11 85 46 28 10 - a4 41 25 9 75 37 23
