Abstract: Rigid-flexible coupling dynamic performance of an elastoplastic beam with large deformation was investigated. Based on nonlinear constitutive relation and nonlinear strain-displacement relationship, and using exact expression of curvature, dynamics variational equations for an elasto-plastic beam with large deformation were established using virtual work principle and absolute nodal coordinate formulation. Finite element method was used for discretization, and then rigid-flexible coupling dynamic equations were established. The simulations of a single pendulum under gravity show that elasto-plastic strain leads to the increase of the absolute value of the average transverse deformation and the decrease of transverse vibration amplitude. Furthermore, the comparison of the present nonlinear formulation with oneorder approximate dynamic model based on the theory of small deformation shows that the present result is stable for large deformation problem.

Key words: large deformation, elastoplastic beam, nonlinear constitutive relation, dynamics