刚性质量对自由梁的弹粘塑性次撞击

Elastic Viscoplastic Sub-impacts of Free-free Beam Struck by Rigid Mass

采用过应力模型,考虑局部撞击接触变形和自由梁动力响应中的材料应变率效应,提出能够考虑多次撞击接触行为的单轴压缩弹粘塑性局部接触变形模型,并结合有限差分方法和撞击与分离条件,研究刚性质量水平撞击弹粘塑性自由梁的全过程。研究发现,该水平撞击过程实际上是一个复杂的弹粘塑性次撞击过程,梁材料的应变率效应在局部接触变形行为和自由梁的动力响应行为中有着显著的作用,导致撞击力幅值、弹性变形和塑性变形等发生明显的变化。通过与三维动力有限元法的计算结果的比较表明,所提方法是合理的。

By employing the overstress model,the effect of strain rate on local elastic viscoplastic contact deformation and free-free beam dynamics is considered.A local elastic viscoplastic uniaxial compression deformation model is presented to take into account the multiple impact-contact deformations.By the use of the finite difference method and the impact and separation conditions,the sub-impact phenomenon of a free-free beam horizontally stuck by a rigid mass is investigated.It is found that the horizontal impact is indeed a complicated process including elastic viscoplastic sub-impacts.The effect of strain rate of the beam has a significant role in local contact deformation and beam dynamics.It results in the obvious variations of impact force,elastic deformation and viscoplastic deformation of the beam.The present numerical simulations are compared with those solved by the three-dimensional dynamic finite element method.The comparisons illustrate that the present method is reasonable.