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摘要: 运用一维应力波理论,分析了弹性应力波在分离式Hopkinson压杆(SHPB)实验中的传播过程,推 导出试件和压杆中应力分布相关计算公式。探讨了有关因素对试件应力平衡时间的影响规律,发现试件应力 平衡时间受试件/压杆广义波阻抗比和入射加载升时的影响显著,而不受试件/压杆截面积比和入射加载应力 幅值的影响。结合岩石SHPB实验,计算分析了不同入射加载应力幅值在不同入射加载升时情况下,试件达 到应力平衡时的应变变化特征,并提出了降低试件在应力平衡时的应变控制方法,使试件在未达到断裂应变 之前达到应力平衡,以保证实验的有效性。得出的结论对岩石类脆性材料SHPB实验方案设计具有一定的 参考意义。Abstract: Basedontheone-dimensionalstresswavetheory,theelasticstresswavepropagationinthe splitHopkinsonpressurebar(SHPB)experimentwasanalyzedandthecalculationformulaforthe stressdistributioninthespecimenandthepressurebarwasobtained.Andsomefactorsinfluencing thetimeforthestressequilibriumwerediscussed.Theresultsshowthatthetimeforthestressequilibriumismarkedlyaffectedbythenominalspecimen- to-barimpedanceratioandtheincidentwaverisingtimeandhasnorelevancewiththespecimen- to-barsectionarearatioandtheincidentwavestress amplitude.BycombiningwiththeSHPBexperiment,thestrainchangecharacteristicsoftherock specimensachievingstressequilibrium wereinvestigatedfordifferentincidentstressamplitudesand variousincidentrisingtimes.Andsomemethodsforreducingstrainwereputforwardtomakesure thespecimenachievestressequilibriumbeforefracturetoensurethetestsvalid.TheconclusionsobtainedcanprovidesomereferencesforthedesignoftheSHPBexperimentsonbrittlematerialslike rock.
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Key words:
- solidmechanics /
- stressequilibrium
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