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摘要: 采用线性关系式及多项式对爆炸膨胀环速度曲线上不同长度的数据窗口进行拟合,获得了应力应 变关系,结果表明数据窗口的选取是膨胀环实验数据处理的基础;同时发现当拟合关系式高于2次时,获得的 应力应变关系从形式上偏离了物理规律。对数据进行高阶光滑后采用差分方法直接处理,可以更好地反映膨 胀环速度历史与瞬时应力之间的关系,澄清了2次以上关系式拟合处理得到的应力应变关系偏离物理规律并 不是由数据处理方法造成的,而是由速度点测试的不确定性造成的。Abstract: Abstract:Themovementofafreelyexpandingringwasanalyzedandtheradialvelocity-timecurveof theexpandingOFHCcopperringwasexperimentallyobtainedbythelaserinterferencetechnique. Thedifferentdatawindowswerechosenfromtheobtainedvelocity-timecurveandtheintercepteddata inthedifferentwindowswerefittedbydifferentmethods.Thentheaccelerationswereacquiredfrom thedifferentialequationsofthevelocities.Thestress-straincurvesweregainedbyprocessingthevelocitiesoftheringunderone- dimensionalstressassumption.Resultsshowthatthereasonableselectionofdatawindowsisthecorrectdata- processingfoundationforexpandingringtests.Whilethe ranksoffittingexpressionsarehigherthan2,theobtainedstress-strainrelationwilllapseformally fromphysicsrules.Butafterthedata,whicharesmoothedbyhigher-rankexpressions,areprocessed bythedirectdifferencemethod,theprocesseddatacanreflectbettertherelationshipbetweenthevelocityhistoryoftheexpandingringanditsinstantaneousstresses. Itexplainsthatthelapseoftheabovefittedstress- strainrelationfromphysicsrulesdoesnotresultfromthedataprocessingmethods butfromtheuncertaintyofthevelocitymeasurementatonepoint.
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Key words:
- mechanicsofexplosion /
- dataprocessing /
- fittingexpression /
- expandingring /
- difference
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