花岗斑岩Holmquist-Johnson-Cook本构模型参数研究

Study on parameters of Holmquist-Johnson-Cook model for granite porphyry

对取自玉龙铜矿边坡的花岗斑岩进行相关物理和静力学实验,获得岩石的密度、弹性模量、泊松比、单轴抗压强度以及抗拉强度等参数。通过花岗斑岩SHPB实验得到试样的典型冲击动载应力-应变曲线。利用相关实验结果,借助显式动力有限元软件LS-DYNA,得到花岗斑岩的HJC（Holmquist-Johnson-Cook）本构模型参数,分析岩石动载强度对HJC模型参数的敏感性,总结出一套HJC模型参数的取值方法。岩石动载强度对HJC模型的A,B,N和fc参数最为敏感,该参数变化幅度在-30%~30%时,强度变化率大于11%。HJC模型参数的取值过程中,将岩石物理和力学实验数据与数值模拟进行结合,即可体现HJC模型基本理论,又可均衡实验和数值模拟的工作量,并能获得可靠的模型参数,为岩石动载数值模拟计算提供帮助。

Quality, elasticity modulus, poisson ratio, uniaxial compressive strength,and tensile strength of granite porphyry from Yulong copper mine were obtained utilizing the relevant experiments. Typical dynamic stress-strain curves were obtained by SHPB test. Using relevant experimental results and finite element software LS-DYNA, HJC model parameters were got. On the basis of parameter sensitivity analysis,the method for taking values of HJC parameters was obtained. There are four parameters （A , B, N,,C） are sensitive. When the four parameters change between -30 % and 30%, change rate of strength is greater than 11%. By combined with the experimental data and numerical simulation, reliable parameters can be obtained. This method can reflect HJC model based theory and balance workload of experiment and numerical simulation. This study is helpful for numerical simulation of rock dynamics.