花岗岩损伤型黏弹性动态本构模型研究
Research on damage viscoelastic dynamic constitutive model of granite
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摘要: 采用恒应变率SHPB实验装置对花岗岩的动态力学性能进行测试。 结果表明:花岗岩动 态应力-应变曲线在初始加载段呈线弹性,屈服后具有显著的塑性变形特征,屈服应力、峰值应力 和弹性模量均具有应变率相关性。 基于花岗岩动态力学特性,将朱-王-唐(ZWT)模型本构方程 推广到花岗岩材料并对其进行简化,同时考虑冲击荷载作用下损伤对花岗岩动态强度的影响,引 入应变率型损伤演化方程,建立简明的损伤型ZWT动态本构模型。 应用建立的动态本构模型对 SHPB实验测得的应力-应变曲线进行拟合,两者具有较好的一致性,表明构建的动态本构模型 能够较好地反映花岗岩在动载作用下的力学特性。Abstract: DynamicmechanicalpropertiesofgraniteweretestedbyasplitHopkinsonpressurebarsystemwithconstantstrainrate.Theinitialloadingstageofstress-straincurveofgraniteislinearelasticity, andtherockmaterialhasasignificantplasticdeformationafteryielding.Yieldstrength,peakstrength andelasticmodulusareallratedependent.Basedondynamicmechanicalpropertyofgranite,theconstitutiveofZhu-Wang-Tangmodelwassimplifiedto apply on granite,and with consideration of the effectofdamageonthedynamicstrengthofgraniteunderimpactload.Theexperimentaldatawerefitted totheproposedmodel.Thefittedstress-straincurvesatdifferentstrainratesareingoodagreementwith theexperimentalones.Thisdemonstratesthattheproposeddynamicconstitutivemodelinthispapercan accuratelydescribethedynamicmechanicalpropertiesofgraniteundertheimpactload.
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