基于Flat-Joint接触模型的黏弹性动态本构开发及其参数影响分析  

Avisco-elastic dynamic constitutive model based on discrete element method and its application

作　　者：何珣 何勇[1] 潘绪超[1] 郭磊[1,2] HE Xun;HE Yong;PAN Xuchao;GUO Lei(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing,Jiangsu 210094,China;Institute of Rocket Force,Beijing 100094,China)

机构地区：[1]南京理工大学机械工程学院,江苏南京210094 [2]火箭军研究院,北京100094

出　　处：《岩石力学与工程学报》2020年第5期949-960,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金青年基金(11702145);青年科学基金项目(11502118),CAST-BISEE创新基金(2019-037)。

摘　　要：基于离散元方法将黏弹性本构关系引入到Flat-Joint模型中,推导出黏弹性的力–位移更新公式以及率相关黏结键断裂准则,使颗粒间接触力响应和黏结强度表现出率相关性,并通过C++语言生成供颗粒流程序(PFC2D)调用的自定义本构子程序(DLL)。模拟不同应变率条件下的岩石类材料动态压缩过程,得到应力–应变曲线、断裂黏结键数量变化曲线和黏结键断裂时刻分布与应变率之间的关系,分析应变率提高对裂纹生成和分布的影响;同时分析各黏弹性参数对应力–应变曲线和泊松比等宏观参数以及试件变形和破坏特性的影响,可知E1越大,主剪切裂纹越粗壮,E2越小,剪切裂纹和弥散裂纹数量分布越多,而h2参数对主剪切裂纹影响很小,但从主剪切裂纹延伸出的次级裂纹随h2减小而增多。The visco-elastic dynamic constitutive relation is introduced into the Flat-Joint model based on the discrete element method,and a visco-elastic force-displacement formula and a rate-dependent broken criterion of contacts are derived. The rate-dependent force-displacement relationship and bond strength of contacts between particles are obtained. A subroutine(DLL) which could be called by PFC2 D is generated with C++ based on the deduced formulas. By simulating the dynamic compression of rocks under different strain rates,relationships between the stress-strain curve,the quantity change curve of broken contacts and the distribution of broken strain of contacts with the strain rate are obtained,and the effects of the strain rate on the generation and distribution of cracks are analyzed. At the same time,the effects of visco-elastic parameters on the macro-parameters such as stress-strain curves and Poisson’s rate,and deformation and failure characteristics of specimens are also analyzed. It is shown that the larger the elastic coefficient of elastic medium E2 is,the stronger the principal shear crack is,and the smaller the elastic coefficient of Maxwell medium E2 is,the more the shear cracks and dispersive cracks are. The viscous damping coefficient of Maxwell medium h2 has little effect on the principle shear cracks,but the secondary cracks extending from the principal shear cracks increase with decreasing h2.

关 键 词：数值分析 颗粒离散元 黏结键 黏弹性 动态压缩 裂纹 

分 类 号：O231[理学—运筹学与控制论]