基于连续接触力方法的接触碰撞问题研究

Study on Contact Impact Problem Based on Continuous Contact Force Method

摘要: 考虑摩擦的碰撞过程中接触点切向状态的改变会导致切向摩擦力方向及大小的不同，如果直接将经典的瞬时碰撞假设用于含摩擦的物体碰撞问题会导致在一定的条件下出现碰撞前后能量不协调的现象。本文采用连续接触力的方法建立接触碰撞模型，其中法向采用非线性阻尼弹簧模型，切向采用非光滑库仑摩擦模型。针对均质杆与地面斜碰撞的经典例子，对碰撞过程进行动力学模拟。研究不同的初始位形、初始速度及摩擦系数下系统运动的变化规律及相应的滑动模式，并通过该模型，展示了碰撞过程中复杂的切向滑动模式，为碰撞模型的正确选择提供参考依据。

Abstract: For collision with friction, the change of the state of tangential motion of contact point may cause the change of direction and magnitude of the frictional force. The direct use of the traditional instantaneous collision hypothesis may cause the energy inconsistence. Contact-impact model is built based on continuous contact force method. In this model nonlinear damping spring model is used on normal and non-smooth Coulomb friction model is used on tangential. The classic example of oblique impact is a rigid body system consisted by a member bar and ground. Dynamics simulations are done in the process of impact for this classic example. Study the movement variation and the corresponding sliding mode of this system on different friction coefficients, different initial velocity and different initial configuration. With this model, the complex tangential sliding mode during the impact process is demonstrated, which provide the basis for the choice of the collision model.