摘要
为了建立颗粒材料的组构张量与应力张量的定量关系,采用离散单元法,开展了一系列等应力比双轴压缩试验.模拟结果表明,随着应力的增加,颗粒间的接触法向朝着大主应力的方向集中,试样的各向异性程度逐渐提高.当应力足够大时,由接触法向定义的组构张量将不再发生演化,对应的第二偏不变量与应力比大致呈二次函数关系.进一步,将组构张量与应力张量按照某种形式相乘,得到的组合张量是与应力比无关的常量,这表明组构张量与应力张量的关系可以用一个隐式方程来描述.从而在特定条件,即圆形颗粒材料在等应力比加载下颗粒排列达到稳定时,确定了宏细观物理量之间的定量关系,为建立多尺度的本构模型提供一种潜在思路.
To establish a quantitative relation between the fabric tensor and stress tensor of granular materials,a series of constant stress ratio biaxial compression tests were conducted in this paper using the discrete element method.Simulation results show that as the stress increases,contact normals between particles concentrate towards the major principal stress direction,so that the anisotropic degree of the sample gradually increases.When the stress is large enough,the fabric tensor defined by the contact normal direction no longer evolves,and its corresponding second partial invariant satisfies a quadratic function of the stress ratio approximately.Furthermore,if the fabric tensor and stress tensor are multiplied in a certain form,one can obtain a joint tensor that is independent of the stress ratio,which indicates that the relation between the fabric tensor and the stress tensor can be described by an implicit equation.Accordingly,under a specific condition where the particle arrangement of circular granular material reaches stable under constant stress ratio loading,quantitative relationship between macro and micro physical variables is determined,which provides a potential idea for the establishment of multiscale constitutive models.
作者
路德春
张世浩
田雨
杜修力
LU Dechun;ZHANG Shihao;TIAN Yu;DU Xiuli(Institute of Geotechnical and Underground Engineering,Beijing University of Technology,Beijing 100124,China)
出处
《北京工业大学学报》
CAS
CSCD
北大核心
2021年第7期728-735,共8页
Journal of Beijing University of Technology
基金
国家自然科学基金资助项目(51908010,52025084)
北京市自然科学基金资助项目(8204055)。
关键词
颗粒材料
宏细观联系
组构张量
应力张量
等应力比
离散元模拟
granular material
macro-micro relation
fabric tensor
stress tensor
constant stress ratio
discrete element simulation
