颗粒振动及耗能特性研究的弹塑性接触建模方法

提出一种颗粒弹塑性接触的通用建模方法来研究颗粒系统的振动及耗能特性.构造颗粒法向塑性接触本构方程基本形式，并采用有限元法(FEM)获得无量纲本构关系;提出颗粒弹塑性细观接触加-卸载多路径模型，给出了颗粒塑性接触能量耗散的计算公式.采用离散单元法(DEM)对简谐激励下颗粒系统的振动和耗能特性进行了数值仿真分析.结果表明，颗粒使系统产生非线性振动，颗粒介质在系统进入共振区的前后均呈现出类似混沌的复杂非线性运动状态.颗粒间的法向塑性接触没有改变颗粒阻尼效应的主要耗能方式，但对颗粒动态接触行为及颗粒系统动力学特性产生重要影响.

A Modeling Approach of Elastoplastic Contact for Analyzing the Vibration and Energy Dissipation Characteristics of Particles

A general contact modeling method of elastoplastic contact between particles is proposed to study the vibration and energy dissipation characteristics of the particle system. The basic form of constitutive equation concerning normal plasticity contact between particles is established and a dimensionless constitutive relation can be obtained based on the finite element method accordingly. A loading-unloading multipath model of elastoplastic contact between particles is presented. A theoretical formula of normal plastic energy dissipation is deduced. Based on the discrete element method， numerical simulations on the characteristics of vibration and energy dissipation for the particle system under harmonic excitation are carried out. The results show that the linear system exhibits the characteristics of nonlinear vibration caused by particles. Granular media appears to be a complicated nonlinear state of motion similar to the chaos near the resonance region. Although the way of energy dissipation on particle damping effect remains unchanged， normal plastic contact alters the dynamic contact behavior between particles and has great influence on the dynamic characteristics of the vibrating particle system.