考虑摩擦的柔性多体系统斜碰撞理论与实验研究

摘要

基于模态综合技术提出了适用于求解柔性多体系统斜碰撞问题的动力学建模方法,将离散的碰撞物体分为碰撞区域和非碰撞区域,对于非碰撞区域采用子结构方法进行模态缩减,在保证求解精度同时能有效提高计算效率.用罚函数模型和修正库伦摩擦模型分别对法向和切向碰撞进行建模,考虑钢杆和PVC圆盘的接触碰撞系统,在考虑摩擦的斜碰撞工况下分别采用电阻应变片和3D-DIC测量技术测量圆盘表面指定点的应变响应和速度响应,通过理论和实验结果对比验证了碰撞动力学模型和摩擦模型的准确性,同时研究了相对速度的变化对摩擦因数的影响.%A dynamic formulation based on the component mode synthesis method was proposed for solving the oblique contact-impact problems in multibody systems.The contact bodies were divided into the contact zone part and uncontact zone part.The degrees of freedom of the un-contact zone part were reduced by the modal reduction,which improves the computational efficiency on condition that the accuracy is guaranteed.Impacts in the normal direction and tangential direction were modeled using the penalty method and the modified Coulumb friction model respectively.A contact system consisting a steel rod and a PVC plate was considered.An eccentric collision considering the friction effects was investigated experimentally,and the strain and velocity response of the plate were measured by the strain gauges and the 3D-DIC measuring technique.The comparison between the numerical results and experimental results proves the accuracy of the formulation proposed.Meanwhile,the influence of the relative velocity on the friction coefficient was investigated.