구조부재의 충돌해석을 위한 유한요소 극한해석의 동적 수식화

Abstract

In this paper, the limit analysis concept is extended to consider the dynamic equilibrium condition considering the inertia and stain-rate effects instead of the static equilibrium. A dynamic formulation for the limit analysis has been derived fur incremental analysis dealing with time integration, strain and stress evaluation, strain hardening, stain-rate hardening and thermal softening The time dependent term in the governing equation is integrated with the WBZ-a method which proposed by Wood, Bossak and Zienkiewicz. The dynamic material behavior is modeled by the Johnson-Cook relation in order to consider strain-rate hardening and thermal softening as well as strain hardening. Simulations have been carried out far crush analysis of structure members and numerical results are compared with elastic-plastic analysis results by ABAQUS/standard and LS-DYNA3D. Comparison demonstrates that the dynamic finite element limit analysis can predict the crachworthiness of structural members effectively with less computing time and effort than the commercial codes compared. The crashworthiness of the structure with the rate-dependent constitutive model is also compared to the one with the quasi-static constitutive relation for demonstration.