Abstract: 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. The 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 convergence 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.

Key words: Dynamic substructure method, Elastic-viscoplastic wave, Flexible structure, Impact, Numerical method