作大范围运动柔性梁的一种碰撞动力学求解方法

研究作大范围运动柔性梁的碰撞动力学问题。针对梁碰撞前、碰撞过程、碰撞后三个阶段，分别建立各阶段的动力学方程。基于柔性多体系统刚柔耦合动力学理论，建立梁无碰撞时的刚柔耦合动力学方程。结合冲量动量法和接触约束法提出一种碰撞动力学求解方法，先以冲量动量法实现运动转换得到协调的碰撞初始条件，再以接触约束法求解碰撞过程。导出系统的刚柔耦合碰撞动力学方程，给出了接触、分离判据，实现三个不同阶段的转换与动力学求解。编制仿真软件，对实例进行动力学仿真，得到系统不同阶段的动力学响应。研究表明，所提碰撞求解方法可以较方便地用于计算柔性多体系统的碰撞问题。梁的柔性、大范围运动及碰撞效应相互耦合，碰撞行为对于柔性多体系统碰撞过程和碰撞后的全局动力学性态均产生较大的影响。

Method for Solving the Impact Problem of a Flexible Beam with Large Overall Motion

The impact dynamics of a flexible beam with large overall motion is investigated. The dynamic equations in three periods (before, during, and after impact) are established respectively. Based on the rigid-flexible coupling dynamic theory of flexible multibody systems, the dynamic equations of the flexible beam without impact are established. A method for solving the impact dynamics is proposed, combined the impulse-momentum method and the contact constraint method. The impulse-momentum method is used to achieve kinematic transform, and the contact constraint method is used to solve the impact process. The system’s impact dynamic equations are obtained, and the contact/separation criterion is given to realize the kinematic transform and dynamic solution. The simulation program is developed, and the dynamic response in different periods of a simulation example is given. It is shown that the impact solving method given can calculate the flexible multibody system’s impact problem conveniently. The flexibility, the large overall motion, and the impact effect are coupled. And the impact makes great influence on the flexible multibody system’s global dynamics during and after the impact process.