为了研究作大范围回转运动的柔性梁与固定刚性质量发生正碰撞的动力学问题,该文以柔性多体系统刚柔耦合动力学理论为基础,考虑非线性耦合变形项和碰撞力势能概念,利用假设模态法和Lagrange方程建立了含碰撞力的系统刚柔耦合动力学方程。该方程可以处理系统无碰撞和有碰撞的全局动力学问题。基于单轴压缩弹塑性接触模型将接触碰撞过程分为弹性加载、塑性加载和弹性卸载3个阶段,给出了描述碰撞过程的方法和接触判定条件。碰撞动力学仿真算例描述了碰撞过程中的碰撞力、变形、角位移等动力学特性。弹塑性接触模型与非线性弹簧阻尼模型的仿真结果对比发现,两种接触模型描述接触碰撞阶段和碰撞能量损失的方法不同,得到的碰撞力大小亦不同;弹塑性接触模型更接近实际情况,适用性较强。
To study the impact dynamics of the radially rotating flexible beam and the fixed rigid mass,based on the rigid-flexible coupling dynamic theory of the flexible multibody system,the rigid-flexible coupling dynamic equations with the impact force are established by using the assumed mode method and Lagrange equations.These equations contain the nonlinear coupling deformation item and the impact force potential energy,and can deal with the global dynamics of the impact system and no impact system.The impact process is divided into three stages of the elastic loading,the plastic loading and the elastic unloading by the uniaxial compression elastic-plastic contact model,and the describing method of the impact process and the contact judging condition are given.The dynamic characteristics including the impact force,the deformation and the angular displacement of the impact process are described by an impact dynamic simulation example.The comparation of the elastic-plastic model and the spring-damper model show that the impact forces of the two models are different due to the different descriptions on the impact stages and the impact energy loss,and the elastic-plastic contact model is more practical and applicable.