请问谁知道Halt的随机振动怎么算加速因子

最近用Halt试验箱子做HASS测试,目的是剔除缺陷产品;但想做的更多的,可找了很多资料都没有找到随机振动加速因子的计算方法;
哪位兄弟要知道,分享下,谢谢!

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可靠性技术新手提问

包装运输实验相关(SJ-108-3213.pdf)

2010-1-25 16:34:24

可靠性技术可靠性试验

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2010-1-26 19:26:10

20 条回复 A文章作者 M管理员
  1. coldd

    很久前看过一本书,《可靠性强化试验理论与应用》,可能有这类问题的说明,你买本看看

  2. Bluflower

    能共享,公式所参考的文献吗

  3. lipper

    谢谢分享 ,具体出资哪里啊

  4. forest_sheep

    [quote][url=pid=78195&ptid=8097]ice_fang发表于2010-7-1011:06[/url]
    Example:UsingtheVibrationmodel
    Problem:
    Estimatethetesttimetosimulate10yearsoflifei…[/quote]

    第一次看见振动加速参数,学习了

  5. justinbk

    可以参考一下MIL-std-810F。[b]回复[url=http://kekaoxing2011.host4.288idc.com/club/redirect.php?goto=findpost&pid=70107&ptid=8097]1#[/url][i]pif2216[/i][/b]

  6. sounnyday

    楼上的应该是某家的试验数据吧~

    小弟手边也有类似的数据
    不过在IECorMIL标准上也没有这样的叙述

  7. @@那@@

    学习学习!

  8. yeh

    HALT模拟的振动模型与MIL-STD810E振动模型是相似的吗?

  9. pif2216

    Thankssomuch!

  10. ice_fang

    DearAll,
    Sorry,mybossoncegivemeapaperliteraturewhichdescribevibrationmodel.SoIshareitwithall.
    Iquoteasectionforyourreference.
    InVibration,devicesaremountedonadynamicshakertableandsubjecttoeitherarandomorsinusoidal-typevibrationprofile.CommonrandomvibrationtestsaremostfrequentlyspecifiedintermsofPowerSpectralDensity(PSD)levels(seebelowFigure).FigureillustratesthepossiblePSDtestprofilelevelsrelatedtoasimilarparticularuseenvironment.ThePSDfunctiondescribesthedistributionofvibrationenergywithrespecttofrequency.TheamountoftimecompressionthatcanbeaccomplishedisrelatedtothePSDtestlevelanduselevel.Estimatesoftimecompressioncanbemadeoncetheuselevelestimateandspectraldensityprofileareestablished.Thetraditionalclassicaltime-compressionmodel(MIL-STD810E)isapowerlawmodel(seebelowFigure).Inapplyingthismodel,itisimportanttounderstandthefailuremechanismsince,inarandomvibration-loadingenvironment,theresonanceofthematerialcandominatethefatiguelife.Here,maximumvibrationamplitudesandstressoccur.However,fatiguefailuresarenotalwaysdominatedbythefundamentalresonancemode.Inpractice,manyofthestresspeaksintheuseenvironmentmayfallbelowthefatiguelimitofthematerial,whileotherswillbeabovethefatiguelimit.Itfollowsthatanacceleratedlifetestbaseduponthismodelshouldinherentlybeconservative.However,becausemostofthefatiguedamageoccursatthehigheststresspeaksinboththetestandinactualuse,thedegreeofconservatismisnotexcessive.AsnotedinbelowFigure,thePSDisinunitsofG2/Hz.ThesquareoftheGstresslevelattheresonancefrequencyisdirectlyproportionaltothePSDlevel(W~G2),sothemodelcanbeputintermsofeitherrandomorsinusoidal-resonanceG-stressloading.Inthemodel,thefatigueparameterisrelatedtoexperimentalslopeofthestresstocyclestofailuredata.Thisexponentvariesdependingonthefatiguelifeofthematerialsinvolved.Forexample,thevalueofb≈5iscommonlyusedforelectronicboards.However,conservativevalueforthefatigueparameterbisabout8(e.g.,Mb=4).MILSTD-810E(514.4-46)recommendsb=8forrandomloading.

    Fig.JPG

  11. pif2216

    [b]回复[url=pid=78195&ptid=8097]7#[/url][i]ice_fang[/i][/b]
    真的非常感谢你的分享!仔细看了下你分享的内容,有些问题还需要向你请教:
    1)M_b=b/2wherebisthefatigueparameter这个参数怎么确定?比如你举的例子中AV=(WStress/WUse)Mb=(0.12/0.03)4=256的[b]4[/b]是怎么确定的?
    2)G_f=resonantGsinusoidvibrationlevel怎么用的是正玄共振等级?不是随机振动么?正玄共振等级如何确定其值?
    3)C=constant如何取值?
    4)PSDLevel的值是实验根据具体产品得出还是共用的?比如
    Level2:Avg.PSD=0.06G2/HZ(Content11GRMS)
    Level4:Avg.PSD=0.12G2/HZ(Content15.5GRMS)
    Level8:Avg.PSD=0.24G2/HZ(Content21.9GRMS)
    Level16:Avg.PSD=0.48G2/HZ(Content31GRMS)
    还有你Level1PSD=0.03G2/HZ是推算的么?还是试验得出的?

    5)最后一个问题,和楼上一个兄弟一样的,就是不知道兄弟这些公式和资料是出自什么文件上的阿?能共享下么?

    [b]真的再次感谢!!!!!!![/b]

  12. ZICO863

    [quote]A_V=T_Use/T_Stress=(W_Stress/W_Use)^(M_b)
    (W_Stress/W_Use)^(M_b)=(G_(f_Stress)/G_(f_Use))^(…
    ice_fang发表于2010-7-1010:56[url=pid=78194&ptid=8097][/url][/quote]

    请教:该公式源于哪个标准或文献?

  13. pif2216

    谢谢,学习了;有相关案例就更好了

  14. ice_fang

    Example:UsingtheVibrationmodel
    [b]Problem:[/b]
    Estimatethetesttimetosimulate10yearsoflifeinthefieldforanassembly
    thatistestedtoaLevel4PSDrandomvibrationtestcondition,shownin
    below[b]Remark[/b]description.Itisestimatedthattheassemblywillundergoaworst-caseLevel1-
    typerandomvibrationexposure1percentoftheassembly’slife.Therestof
    theassembly’slifeisrelativelybenignintermsofvibrationexposure.
    [b]Solution:[/b]
    First,usetheexpressionin[b]previousletter[/b]tofindthevibrationaccelerationfactor.SinceLevel4hasa
    PSDof0.12G2/Hz,thenLevel1is0.03G2/Hz.
    Therefore,
    AV=(WStress/WUse)Mb=(0.12/0.03)4=256.
    In10years,thedevicewillbeexposedtoaLevel1vibrationforabout87,600×0.01=876hours.
    Therefore,thenumberoftestcyclestosimulatethisis
    TStress=TUse/AV=876/256=3.5hours.

    [b]Remark:CommonrandomvibrationtestsaremostfrequentlyspecifiedintermsofPowerSpectralDensity(PSD)levels[/b]
    Level2:Avg.PSD=0.06G2/HZ(Content11GRMS)
    Level4:Avg.PSD=0.12G2/HZ(Content15.5GRMS)
    Level8:Avg.PSD=0.24G2/HZ(Content21.9GRMS)
    Level16:Avg.PSD=0.48G2/HZ(Content31GRMS)

  15. ice_fang

    A_V=T_Use/T_Stress=(W_Stress/W_Use)^(M_b)
    (W_Stress/W_Use)^(M_b)=(G_(f_Stress)/G_(f_Use))^(2M_b)
    Ln(tf)=C-M_bLn(W)

    Where,
    A_V=vibrationaccelerationfactor
    T_Stress=vibrationduration
    T_Use=vibrationduration(nominal)
    W=randomvibrationinputPSDacross
    theresonancebandwidth(G2/Hz)
    W_StressisthePSDteststressand
    W_UsenominalusePSD
    G_f=resonantGsinusoidvibrationlevel
    M_b=b/2wherebisthefatigueparameter
    tf=timetofailure
    C=constant

  16. admin

    [b]回复[url=pid=77134&ptid=8097]4#[/url][i]fuckit[/i][/b]

    了解一下,希望有更多的高手如fuckit一样,来介绍介绍

  17. fuckit

    忘记在哪里看到过的
    振动的加速因子使用G值用逆幂模型(PowerLaw)进行计算的

  18. deadxiaoh

    有正常的振动的加速因子计算吗?????想交流一下

  19. admin

    没听过Halt试验中的随机振动计算加速因子

    做HASS时,根据HALT试验得到的值,取一个百分比而已。

    楼主可以再把问题描述清楚一些,为什么要计算随机振动的加速因子。目的是什么,以你的理解,大概如何计算????

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