1、NIH.-ID3K-781Ao9(jSUPERSEDINGMIL-HDBK-78114 JULY 1987MIL-STD-781D17 OCT 1986DEPARTMENT OF DEFENSEHANDBOOKFORRELMBILITY TEST METHODS, PLANS, ANDENVIRONMENTS FORENGIIWERING, DEVELOPMENTQUALIFICATION,AND PRODUCTIONDoThis handbook is for guidance only.not cite this document as a requirement.J:?V hTEST M
2、ETHODS AND TEST PLANS . . 9Reliability test program 9Integrated reliability test planning 9i!Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Paragraph!MIL-HDBK-781CONTENTS (Continued)Page4.34.3.14.3.1.14.3.1.24.3,1.34.3.1.44.3.1.54.44.4,14,4.24.54.5.
3、14.5.24.5.34.64.6.14.6.1.14.6.1.24.6.1.34.6.144.6.1.54.74715.5.15.25.215.2.1.15.2.1.25.2.1 .2.15.2.1 .2.25.2.1 .2.352.25.31532. . . .,., ,Environmental test conditions . . . . Combined environmental test conditions .9Electncd stress .9Vibration stress .99Thermal stress .9Moisture .l OEquipment cycli
4、ng l OTest instrumentation and facilities !loTolermce oftestentirommts l OCalibration oftest apparatus . . . 10Performance baselines . . . . . . . . .10Pretest petiommce .i.l OPeflommce during test l OPost.test fiommce llFailure reporting, analysis and correction action systemCAS) llProblem mdftilur
5、e repotting llIdentification and control of fded items !. 11Problem and failure investigations .l 1Ftilure verification llCorrective action . . . . . .Probiem and ftilure tracking and closeout .12. 11Failure categories l2Failure classification 12RECOMMENDED COMBINED ENVIRONMENTAL TESTCONDITIONS $.!1
6、3Puose .l3Test plting l3Integrated reliability testing . . . . . . .13Reliabili ohplating l3Reliability test reviews 14Test readiness reviews !.l4Status reviews .14Test completion review .o.$.l4Application Matrix . . . . . 16Test methods 16(howth monitoring method . . . . . 16Durabihty/economic life
7、 test . . . . . . . . 16ESS elraluation methods 16Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Paragraph5.3,353.3.15.3,3.25.45.4.15.4.25.4.2.15,4.2.25.4.2.35.4.2.45.2.4.55.55.5.15.5.1.15.51.25.5.1,35.5.1.45525.5.2.15.5.2.25.5.2.35,65.75.7. )5.7.25
8、,7,35.7.3.15.7.3.25,85,8.15.8.25.95,9.15.9.259.35.945955.9.659.75971M11mHD13K-781CONTENTS (Continued)PageTest ohms. . !16MTBF assurance test ,. 16Standard test pians l7Test methods mdtestplm sdection factors l7Test method andtest plan selection .l7Test method mdtestplm pmeter selection., 18Equipment
9、 performance 18Equipment qumtity .l8Test duration 18Decision risks . 9Discrimination ratio 19Reliability development/growth evaluation methods. . 19The Duane method !c.2oSymbols 2oConstmion ofameplot 4.2OExample. .2lProblems of plotting average failure rate .22The AMSAA Method . .23Determination oft
10、rendfiom test data 23Reliability growth analysis .24Illustrative exmple .26I)urability/econmic Me test 28ESS monitoring methods 30Computed ESStime intenal method .3OGraphical method .ooo3lStandard ESS . . . 31Themalstress .3lVibration qress . 32MTBF assurance test 32Derivation ofuation 34Prmdure .35
11、Squentid test plms .$.c35Symbols 37Applications !. 37Theoretical background 37Test tmncation 4OSequential test example. ., 40Standard PRST accept-reject criteria and OC curves .42Cotidence limits forsequential tests .42Confidence limits at acceptance.,., . . 43YProvided by IHSNot for ResaleNo reprod
12、uction or networking permitted without license from IHS-,-,-MIL-HDBK-781CONTENTS (Continued)-Paragraph59.7.1.15.9.7,25.9.7.2.15.9.85.9,8.15.105.10.15.10.25.10.35.1045.10.4.15.10.55.10.65.10.75.10.85.10.8.15.10.8.1.15.10.8.25.10.8.2,15,10.95.10.105.10.10.15.10.10.2510.10.35.115.1).15.11.25.11.35.11.3
13、.15.11.3.25.11.3.35.11.45.125.12.15,12.251235.124512526PageExample: black box X . ,43Confidence limts at rejection .!.44Example: black box X 45Sequential tests: Program Managers assessment 45Procedure . 46Fixed-duration tests 46Spbols 46Example problem . . . . . . . . . . . . . . . . . . . . . . . .
14、 . . . . . . . . . . . . . . . . .! . . . . . . . . . . . . . . . . . . . . . . . . ,. 48Sdudfixd-duration test plmsmd OCcuwes 48Atemative fixed.duration test plas 48Derivation ofdtemative plans 48MTBFestimation fiomobseIved test data .49Exclusion ofhothesis test vaIues . 49Specified cofidmce iewal
15、.49MTBFestimation fiomfixed-duration test plans49MT13Festimation at failure occumence . . 49Exampleat ftilure occurrence .MTBFesthation ataccep_ Example at acceptance Projection of expected field MTBF .Fixed-duration tests: Program Manager. 50. 50. 51. 52s assessment . 52Acwpttimes .52Comparison wit
16、h standard fixed-duration tests 51OCcues . . . . . . . . . . . 52All-equipment production reliability acceptance test plan . 52Test duration . 53Evaluation 53Accept-reject criteria for the all-equipment test 53Acceptance .!. 53Rejection . 53Reaching the boundary line . 53Additional all-equipment pro
17、duction reliability acceptancetest plansc. 54Reliabiiity estimates fiomutit-level results 54CdcuIation methti .54Numerical examples t. 57The case of onlone failure in some subsystem(s) . . 59hestimator of the failure rateupper bound .62Departures from AO method requirements. . . .No observed failure
18、s 64viProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ParagraphMIL-HDBK-781CONTENTS (Continued)Page5.1275.12.86.6.16.1.16.26.36,3.16.3.26.46.416.4.26.436.56.5.16.5.26.5.36.5.46.66.6.16.6.1.1.6.6.1 .1.16.6.1 .1.26.6.1 .1.36.61.26.61.2.16.6.1 .2.26.6,1
19、 .2.36.6.1.36.6.1 .3.16.6.1 .3.26.6.1 .3.36.6.26.6.2.16,6.226.6.2.36.6.2.4.66.36031Type I censoring . . 64Computer program . 65TEST INSTRUMENTATION AND FACILITIES . 67Purpose .!.,.,.0. 67Scope . 67Thermal and Vibration Suey . 67Mission and life-cycle environmental profiles and test conditions . 68Mi
20、ssion and life cycle environmental profiles . 68Entiromental test renditions .68Combined environments for fixed-ground equipment . 68Electronic stress and duty cycle .68Thermal stress .!.69Hutidity .69Combined environments for mobile ground equipment 69Electrical stress and duty cycle 69Vibration st
21、ress 70Thermal stress . 70Moisture . 71Combined environments for shipboard and underwatervehicle equipments 71Navdsutiace crafi 7lExternally mounted equipment ,.0 71Electrical stress mddutycycle 7lVibration stress . .71Temperature andhutitidy stress . 71lntemally mounted uipment . 72Electrical stres
22、s andduty cycle 72Vibration stress .0. 72Temperature mdhutidity stress .72Internally mounted equipment, temperature controlled space . 73Electrical stress and duty cycle 73Vibration stress . 73Temperature andhumidity stress profiie 73Naval submarine 74Elwtrical andduty cycle stress 74Vibration stres
23、s 74Temperature and humidity stress profile 74Moisture .75Marine crafl (Army). . . . . . 75Thermal stress - 75vii1Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ParagraphMIL-HDBK-781CONTENTS (Continued)Page6.6.3.26,6.3.36.6.46.76.7.16.7.26.7.2.16.7.
24、2.26.7.2.367.2.46.7.2.4.16.7.2.4.26.7.2.4.36.7.2.56.7.2.66.7.2.76.7.2.86.7.367.46.7.4.167.426.7.4.36.7.4.46.7.56,7.5.16.7.5.26.7.5.36.7.5.46.7.5.4.16.7.5.4.26.7.5.4.36,7.5.4,46.7.5.4.56.7.5.5686.8.16.8.1.16.8.1.2gpVibration stress 75Electrical stress d duty cycle 75Undenvater vehicles 0.0.!,!.,., 75
25、Combined environments for jet aircrafi equipment .75Mission profiles 75Environmental test profiles 76Mission phase (temperature mode) .! 77Duration . 77Mtitude mdMachnumber 77Compment temperature 77hbimt.cooled equipment 78Supplementally cooldequipment .79Temperature rate of change . 79Vibration - 8
26、0Hutidity 8lEquipment operation . 81El.ndwress . 81Construction of an environmental profile . 81Test profile development . 81Vibration 82Tempmature . 82Example of test profile 82Test profiles forvanous aircrti es .82Composite environmental test profile for multimissionapplications 83Required informa
27、tion 83Temperature .83Vibration 84Construction of thecomposite test profile .- 85Temperature 0. 85Vibration .! 86Humidity .86Equipmmt operation .“. 86Electrical stress . 86Example of composity test profile .!. 86Combined environments for VKTOL equipment . 87Missiondascription . . . . . . 87Te AV/STO
28、L tissions . 88Type BV/STOL missions. . . 88Thermal stress 88.LIll _ . .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ParagraphMI L-HDBK-781CONTENTS (Continued)Page6.8.36.8,46.8,56.8,66.8,76.96,9.16.9.1,16.9.1.26.91.36.9.1.46.9.1.56.9.1.66.9.26.9.2
29、.16.9,2.26.9.2.36.106.10.16.10.26.10.2.16.10.2.26.10,2.36.10.2.46.10.2.4.16.10.2.4.26.10.2.4.36.10.2.56.10,2.5.16.10.2.5.26.10.2.66.10.2.6.16.10.2.6.26,10,36116.11 16111161112Vibration stress . . . .88Electrical stress ,. ,. 89Humidity .,., . 89Equipment operation .89Test profiles 89Combined environ
30、ments for turbopropeller aircraft andhelicopter equipment . 89Turbopropeller aircrafi environments 4. 89Electrical stress .89Vibration . 89Themdstress .89Hutidity stress .89Supplementally cooled equipment .9OChmbertir hufidity 9OHelicopter environments . 90Electrical stress, 90Vibration 9OThermal st
31、ress . 90Combined environments for air-launched weapons andassembled external stores 90Wssion profiles .t9lEnvironmental test profiles $. 91Wssionphase .93Duration . . 93Eltincd stress .93Vibration stress . .94Equipment petiommce test 94Fully assembled captive-carry stores performance test .94tieral
32、notes o.95Thcmdstmss .95Supplementally cooled equipments !.!. 95Other equipments 96Humidity stress 0.,.,. ,!. ., 96Supplementally cooled equipment . 96Chamber air humidity .,.,.,. ., 96Example of construction of environmental profile 96Missile transportation. handling, and storage 98Rail transport c
33、onciitions . . . . . . ,98Vibration testing . . . . . . . . . . .98Shock testing 99ixProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ParagraphMIL-HDBK-781CONTENTS (Continued)Page611.1.36.11.1.47.7,17.1.17.27.2.17.2.27.2.2.17.2.2.27.2.37.2.47,2.57.2.6
34、88.18.28.38.4Temperature testing .99Test timeline 0.99STWSTRMNTATION FACITES lOOPurpose ,100Scope 4.100Test facilities and apparatus .100Test chambers 100Equipment cooling 0 101Etiemdmoling .l OlIntemdwolant method l OlTest instmmentation 101Calibration mdaccuracy lOlTesting thetest facility . .101I
35、nstallation of theteitem inthetest facili l OlNOTES . . . 103Intendd use l O3SurHtion o.lO3Subject term (keyword) listing .103Changes from previous issue l O3A-= =. = -Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE111111IvvVIVIIVIIIIXAIXBXAXBX
36、ImXIIIXIVxvXVIIXVIIIXIx)0(XXIIXXIIIXxivXxviMIL-HDBK-781CONTENTS (Continued)PageApplication matfix .lO4Summaofvatiables forthc WSmodel .l O5Summary of equations, AMSAA model .106Equation selection guide, AMSAA model 107Critical values of C*Mparametric form of theCramer-Von Mises statistic .lo8Confide
37、nce intervals for MTBF, failure-terminated test .109Confidence intemls for MTBF, time-terminated test .0.,4.110AMS#A model example ! .4111(1 -y) 100 percent standard cofidence limits on MTBF tieraccept decision (lower. e*L(y.i) . 112-116(1 -y) 100 percent standard confidence limits on MTBF afieracce
38、pt decision (upper - e*L(y,i) ,0117-120(1 -y) 100 percent standard confidence limits on MTBF afterreject decision (lower -OL(y,t) . 121-125(1 -y) 100 percent standmd confidence limits on MTE3Ftierreject decision (upper- olL(y,t) . 126-130Summoffixed.duration test plas l3lSumma of high risk fixed-dur
39、ation test plans !,0131Demonstrated MTBF confidence limit multipliers, for failurecdcuIation o.l32Demonstrated MTBFconfidence limit multipliers, for timecalculation !.133Accept times of fixed-duration test plans, Program ManagersAsessment . 134-136Comparison of risks, standard fixed-duration tests v
40、ersusProgram Managers Assessment l37Test times, standard fixed-duration test plans versus ProgramMmagers Assessment l38Failure times forthe numerical example 139Example of correct or it is the ratio of the upper test MT13F(O.) to the lower test MTBF (el) that is, d=e(+e,.3.1.3 . The simukaneous occu
41、rrence of two or more independentfailures. When two or more failed parts are found during troubleshooting and failures cannot beshown to be dependent, multiple failures are presumed to have occurred.3.1.3.1 . The occurrence of WVOor more failures of the same part inidentical or equivalent applicatio
42、ns when the failures are caused by the same basic failuremechanism and the failures occur at a rate which is inconsistent with the parts predicted failurerate.3.1.3.2 . An independent malfimction of equipment under test; a rootcause.3.1.4 Jvleures of . . . . Reliability measurement should be as spec
43、ified in 3.1.4.1through 3.1.4.10.3.1.4.1 . A basic measure of the system reliabilityparameter related to availability and readiness. The total number of system life units, divided bythe total number of events in which the system becomes unavailable to initiate its mission(s),during a stated period o
44、f time.3.1.4.2 T13*al . Demonstrated MTBF interval (W) is theprobable range of true MTBF under test conditions; that is, an interval estimate of MTBF at astated confidence level.(Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-7813.!.4.3 ( i
45、t is a function of the equipment design and the useenvironment. (flp) should be equal to or greater than (O.) in value, to ensure with high probability,that the equipment will be accepted during the reliability qualification test.3.1.4.7 rved ceve . . The observed cumulative failure rate(P(t) at tim
46、e t is equal to the number of relevant system failures N(t) accumulated by t, dividedby t.3.1.4.8 (P. The intensity fimction (P(f) is the change per unit timeof the expected value of N(t), the number of system failures multiplied by time t. This is writtenas:P(t) = dE(N(t)/dtwhere E represents the e
47、xpected value.3.1.4.9 I+F , . The instantaneous MTBF function at t isequal to the reciprocal of the failure rate fimction.3.1.4.10 . . . . A point estimate of reliability equal to theprobability of survival for a specified operating time, t, given that the equipment was operationalat the beginning o
48、f the period.3.1.4.11 . A measure of the realizability taking intoaccount maintenance policy. The total number of life units expended by a given time, divided bythe total number of maintenance events (scheduled and unscheduled) due to that item.31,5 . .Athorough description of all of the major pkmncd cents andconditions associated with one specific mission. A mission profile is one segment of a life-cycleprofile (for example. a missile captive-carry phase or a missile free-ilight phase). The profileProvided by IHSNot for ResaleNo reproduction or netw
