Impact Simply Supported Beam Multiple Elastic-plastic Contact Model, Rigid Mass

Multiple elastoplastic impacts phenomenon, concerning the dynamic mechanical properties of materials, elastoplastic stress wave propagation and plastic dynamic response of structures, has been focused by many researchers recently. Dynamic responses of structures and local contact are closely related in impact problems, and different local contact models might have different effects on the elastoplastic dynamic responses of structures. The paper aims to make a study of simple supported beam struck by round-nose rigid mass, using three different local contact models: Johnson's blunt indentation model (BI model), Uniaxial compression model (UC model) and Elastoplastic shear deformation model (EPS model). The elastoplastic dynamic responses of structures are obtained by finite difference method (FDM), and different responses of the simple supported beam are compared.The main work of the paper is shown as followings:(1) Considering the rotating inertia on the basis of the Euler-Bernoulli beam theory, the basic dynamic equations of elastoplastic simple supported beam subjected to transverse impulsive loading are established and solved by FDM through introduction of time difference method.(2) Three different local contact models' relationships between indentation and contact force on multiple elastoplastic impacts are established. Then dynamic responses of beam are studied in the impact-separation processes, and reasonable switching conditions of impact-separation are given to analyze multiple elastoplastic impacts.(3) Processes of multiple elastoplastic impacts are simulated by VC++ program, and the time history plots of contact force, bending moment, stress and energy disspation are given. The research indicates that local contact models have a relatively great effect on contact force, and the dominant differences reflect on the peak force in the first impact and the two impact clusters. By contrast, the local contact models have a relatively weaker effect on bending moment and stress, as can be reflected in those two stages. There also is little difference in energy distribution. Accounting for a low proportion of the total input energy, local dissipated energy exerts little effect on energy distribution.The conclusion validates the rationality of strucutral plastic dynamics neglecting local deformation in study of the energy disspation.