砂岩Holmquist-Johnson-Cook模型参数确定

HJC模型在混凝土动态破坏数值模拟中应用广泛,但由于模型中包含参数较多,确定参数需要大量实验,目前缺乏准确可信的岩石材料HJC模型参数。为合理确定砂岩HJC模型参数,对取自四川威远的粉砂岩进行相关静力学实验,获得岩石的弹性模量、泊松比、单轴抗压强度以及抗拉强度等参数。应用三轴压缩实验和单轴SHPB冲击实验,分别得到了该砂岩极限面参数、率效应参数、压力参数和损伤模型参数的取值。基于上述模型参数利用有限元程序LS-DYNA对粉砂岩SHPB冲击实验进行数值模拟,结果表明,实验和模拟的应力-应变曲线形态吻合较好,模拟得到的动态峰值强度和峰值应变与实验结果的平均误差均未超过10%,验证了该HJC模型参数实验测定方法的合理性和有效性。

Determination of Holmquist Johnson Cook model parameters for sandstone

HJC model has been widely used to describe the dynamic failure process of concrete.However,due to the reason that HJC model contains many parameters,the accurate determination on the parameters of HJC model for rock materials is a challenge.In this paper,the authors performed some laboratory experiments to determine the HJC parameters of sandstone samples that were collected from Weiyuan City,Sichuan,China.Specifically,the authors determined the elasticity modulus,Poisson’s ratio,and uniaxial compressive strength of sandstone by uniaxial compression experiments,and the tensile strength by Brazilian disk splitting tests.The strength,strain rate,pressure and damage model constants were determined by fitting the HJC model to the experimental data obtained from the triaxial compression tests and uniaxial SHPB tests.The obtained HJC parameters were used to numerically simulate the SHPB tests of the sandstone samples using finite element program LS DYNA.The results show that the stress strain curve predicted by the HJC model is in good agreement with the experimental data.The mean error of dynamic peak stress and corresponding stain obtained by numerical simulation does not exceed 10%.This demonstrates the rationality and validity of the experimental method for determining the HJC parameters.