梯形载荷下圆筒内粒子系统运动的数值仿真

Numerical Simulation for Granular System in Barrel under Ladder Load

活塞在梯形载荷的作用下,对圆筒内由大量钢球粒子组成的粒子系统产生挤压。粒子-粒子、粒子-边界间频繁的发生接触和分离,甚至每一次接触中,也会发生依附和滑动之间的过渡。为了数值仿真这个过程,首先采用快速接触识别算法,找到每一时间步内粒子系统中所有接触粒子对,然后建立了接触粒子对的接触模型。通过跟踪系统中的所有粒子的运动和受力情况,获得了整个粒子系统运动的数值仿真结果。仿真结果表明,在不同的载荷时整个粒子系统存在各自的暂时稳定状态,和实际情况相符,说明了接触模型的正确性。

Because of ladder load acting on piston, piston presses granular system in barrel which is composed of many steel balls. In this process, many contacts and detachments exit at the same time, and the transforms between contact and detachment occur frequently among particle-particle or particle-wall. Even in each contact＇s process, adherence and slippage can convert each other. In order to find all the contact pairs in every time step effectively, fast algorithm for contact detection was used. Contact model for the contact pairs was set up. Through tracking the motions and forces of all the particles, the motions of single steel ball and granular system were obtained. The simulating result proves that granular system has the different temporal steady state under ladder load. The result has good agreement with practice, which proves the validity of contact model.