刚体与弹性半空间重力正向碰撞界面应力特征
Study on interface stress characteristics of normal collision between a rigid body and elastic half space under gravity

刚体与弹性半空间在重力作用下无初速度的接触过程可用碰撞作用描述；碰撞(接触)界面几何形状由刚体接触部分的廓形决定，弹性半空间接触界面各质点元获得刚体重力作用的速度激励后形成应力波向半空间深部传播；碰撞全过程刚体在重力与接触界面反力共同作用下先后经历加速与减速阶段。通过对无初速度的无限长圆柱体在重力作用下侧面与弹性半空间正向碰撞过程的界面应力特征进行分析，推导界面及界面质点元应力脉冲形成过程及其时(碰撞作用时间)、域(界面宽度)规律，为恒定动力作用的有限边界正向碰撞界面应力研究提供参考。
The contact process between rigid body and elastic half space under the condition of gravity and no initial velocity can be described as collision effect, due to the effective action time is short and the motion feature is obvious. The geometry of the collision (contact) interface was determined by the shape of the contact part of the rigid body. The stress wave is formulated when each particle element at the contact interface obtains the velocity excitation acted by the rigid body gravity, and it then propagates towards the deep part of the half space. The rigid body accelerates first and then decelerates under the action of gravity and interface reaction during the whole collision process. In this paper, an analysis was performed to study the characteristics of the interface stress pulse when the lateral surface of an infinite cylinder with no initial velocity is normally collided with an elastic half space under gravity. The stress pulse forming process of the interface and its particle element as well as the laws of time (collision time) and domain (interface width) were derived. The research results are useful for the study of the interface stress of normal collision with finite boundaries acted by constant dynamic force