循环压制下圆筒内硬球颗粒物性演化特征  

Properties evolution characteristics of cylinder confined hard spheres under cyclic compression

作　　者：欧阳鸿武 雷刚 唐昕 孟力平[2] OUYANG Hongwu;LEI Gang;TANG Xin;MENG Liping(School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,Hunan,China;School of Materials Science and Engineering,Central South University,Changsha 410083,Hunan,China)

机构地区：[1]中南大学机电工程学院,湖南长沙410083 [2]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《实验力学》2020年第5期867-876,共10页Journal of Experimental Mechanics

基　　金：国家自然科学基金资助项目(51475475)。

摘　　要：为探明颗粒介质在循环压制下的变形行为和力学响应,采用拓展Janssen模型连续介质理论和循环压制试验对圆筒内硬球颗粒介质的物性演化特征开展研究。颗粒介质受轴向循环压制变形过程中伴随着固-液转变,有利于提高密度分布和力网结构的均匀性。堆积密度0和弹性模量E的演化与循环压制次数n相关:ø(n)=ø0+[ø(∞)—ø0]><(1一e-n/a),E(n)=E0+A1×(l-e-n/β1)+A2×(l-e-n/β2),其中E0+A1+A2=E(∞)。基于拓展Janssen模型计算方法与试验测量相结合,获取压制过程中颗粒介质的应力场、变形场分布情况,以及边界的摩擦状态和颗粒介质弹性模量的演化特征。颗粒介质在循环压制作用下力一位移的迟滞效应随n逐渐减弱,系统趋于力学平衡状态,力学响应表现为类弹性体特征。To study the deformation behavior and mechanical response of spheres in cylindricallyconfined granular medium under cyclic compression,the physical evolution characteristics of hard spheres in cylinder are investigated based on the continuum medium theory of modified Janssen model and cyclic compression experiments.It is found that the solid-to-fluid transition,accompanied by cyclic axial compression deformation,can improve the spatial uniformity of the packing density distribution and force network structure.The evolutions of the packing density φ and elastic modulus E are found as functions of the number of cyclesφ(n)=φ0+[φ(∞)-φ0]×(1-e-n/a),E(n)=E0+A1×(l-e-n/β1)+A2×(l-e-n/β2),where E0+A1+A2=E(∞).The evolution of the elastic modulus and the friction between the medium and the boundary is obtained by a combination of the modified Janssen model and the experimentally derived distribution of stress and deformation fields.An initial force-displacement hysteresis shrinks and asymptotically disappears with n,at which limit the system tends to a mechanical balance state and the granular medium displays an elastic-like behavior.

关 键 词：颗粒介质 循环压制 拓展Janssen模型 堆积密度 弹性模量 

分 类 号：TB30[一般工业技术—材料科学与工程]