自由梁对简支梁的多次弹塑性撞击

Multiple Elastic-plastic Impacts between Free-free Beam and Simply Supported Beam

提出一种将局部弹塑性接触模型与有限差分法相结合,用来研究梁—梁多次弹塑性撞击问题的多次接触撞击分离方法(Multiple contact impact separation,MCIS)。将单轴压缩弹塑性接触变形模型加以推广,应用于多次弹塑性加卸载过程,并采用有限差分方法求解动力学方程组,完整地模拟自由梁与简支梁正交撞击全过程的各次弹塑性撞击。通过与理想刚塑性模型和三维有限元法的对比研究,表明MCIS方法的计算结果可靠,计算效率高。研究发现,梁—梁多次弹塑性撞击现象是由撞击变形响应造成的,它是局部接触变形和结构整体变形相互耦合作用的结果,具有明显的分区特征。另外,相对于第一次撞击,后续撞击过程中的撞击力、撞击冲量和撞击能量损失均是不可忽略的,说明柔性结构的多次弹塑性撞击现象应该予以足够的重视。

A multiple contact impact separation（MCIS） method which combines the local elastic-plastic contact model with the finite difference method is proposed for the research of beam―beam multiple elastic-plastic impact problem.The uniaxial compression elastic-plastic contact deformation model is applied in the multiple elastic-plastic loading and unloading process,and finite difference method is adopted to solve dynamic equations,so as to completely simulate each elastic-plastic impact in the whole orthogonal impact process between a free beam and a simply supported beam.Through comparison to the ideal rigid plastic model and the three-dimensional finite element method（FEM）,it is shown that the calculation result of MCIS method is reliable and its calculation efficiency is high.It is found that the multiple elastic-plastic impact phenomenon between the beams is caused by the response of impact deformation,and it is the result of intercoupling of local contact deformation and global structure deformation,which has an obvious characteristic of divided region of impacts.Comparing to the first impact,the impact force,impact impulse and impact energy loss of subsequent impacts are significant.Hence,sufficient attention should be paid to the phenomenon of multiple elastic-plastic impacts of flexible structure.