Abstract: 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.

Key words: Beam, Elastic viscoplastic deformation, Impact force, Sub-impacts