摘要
基于固定界面模态综合法,将柔性结构划分为多个子结构,采用添加-删除技术处理接触约束,建立柔性结构弹粘塑性碰撞动态子结构模型。考虑冲击载荷作用下出现的材料的应变率效应,采用Cowper-Symonds本构关系,推导柔性结构在模态坐标下的碰撞动力学方程,提出柔性结构碰撞弹粘塑性波传播的动态子结构方法,并通过理论证明主模态的存在性和主模态截断的收敛性。运用该方法分析直杆纵向碰撞和简支梁横向碰撞问题,计算结果表明,弹粘塑性波的传播速度,超应力效应,以及超应力幅值逐步衰减等波传播特征,均符合弹粘塑性波的理论特征。同时,通过将碰撞力和弹粘塑性波的数值计算结果与三维动力有限元解进行对比,验证了该方法的数值收敛性和计算碰撞弹粘塑性波传播的有效性。
A dynamic substructure method is proposed to account for the propagation of elastic-viscoplastic waves in flexible structures excited by impact. An elastic-viscoplastic substructure model considering the effect of strain rate is established. The constitutive relation Cowper-Symonds is adopted to describe effect of strain rate, and an addition-deletion technique is used to account for contact constraints. T^e governing equations of impact bodies in modal coordinates are derived from the finite element theory and the substructure synthesis method. The existence of main modes and -onwrgence of modes truncation are also proved theoretically. The propagations of elastic-viscoplastic waves are calculated in a rod struck longitudinally and a flexible beam struck transversely by a mass. The elastic-viscoplastic wave speed, the overstress phenomenon and the attenuation characteristic of overstress resulted from viscosity are all coincidence with the theory of elastic-viscoplastic waves. The comparisons of the numerical results of the present technique with those of the three-dimensional dynamical finite element show that the present method is convergent in numerical simulation and valid for the propagation of elastic-viscoplastic waves excited by impact.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2013年第1期95-101,共7页
Journal of Mechanical Engineering
基金
国家自然科学基金(10872095)
总装预研重点(21011019)资助项目
关键词
柔性结构
碰撞
弹粘塑性波
动态子结构方法
数值方法
Flexible structure Impact Elastic-viscoplastic wave Dynamic substructure method Numerical method
