梯形载荷下伴随破碎的散粒体系统动力学分析

Dynamic analysis of granular system with fracture under ladder load

为了获得脆性颗粒材料组成的散粒体系统在动载荷作用下的力学响应,对圆筒内散粒体系统在梯形载荷作用下的力学行为进行了数值研究.建立了链接模型、接触模型以及弹簧-球单元破碎模型;基于离散单元法编制了计算程序,分析了梯形载荷作用下的散粒体系统动力学响应;采用OpenGL图形显示了部分颗粒的破碎过程.结果表明,在梯形载荷作用下,对不同的载荷值,散粒体系统存在相应的暂时稳定状态,并且随着载荷大小的递增,系统达到稳定状态的时间越短,系统的变形也越小;计算过程中发现部分粒子发生破碎,且上层粒子首先被冲击破碎,破碎情况最为严重.研究结果对发射装药发射安全性有着重要的理论意义.

In order to obtain the dynamical response of a granular system composed of brittle grains, a granular system in barrel subjected to ladder load is studied. The connective model, contact model and spring-sphere fracture model are established. Computational codes based on the discrete element meth- od are written to analyze the dynamical response of the granular system. The fracture courses of part grains are shown by OpenGL figures. The simulation results prove that the granular system has tempo- rai steady states corresponding to different load values under the ladder load. With the increase in the load, time intervals between two steady states become smaller, and the whole deformations of the granular system become less. In the simulation process, part grains are fractured in the whole granular system. Meanwhile, top grains in the granular system fracture first and the degrees of their fracture are the severest. The results have important theoretical value for the launch safety of ammunition.