考虑后屈曲的板壳大变形分析

LARGE DEFORMATION ANALYSIS OF PLATES AND SHELLS INCLUDING POST-BUCKLING

本文基于修正拉格朗日描述(Updated Lagrangian Description)建立了三维退化板壳有限元大变形增量公式系统。在非线性有限元方程解法上,提出了用初始增量功和当前刚度参数自动选择每级增量中初始荷载增量因子的正负号,完善了自动加载柱面弧长法。为更准确地追踪结构响应中的临界点,文中还建议了实时控制方案。通过数值比较验证了本文建立的板壳非线性分析方法的可靠性。

A large deformation incremental formulation is developed for three-dimensional degenerated plate and shell elements based on updated Lagrangian description in this paper. An improved cylindrical arc-length method is presented for solving nonlinear finite element equation, in which the sigh of initial load increment in each increment is selected according to current stiffness parameter and initial incremental work. In order to trace the critical points more correctly, a real-time control strategy is suggested. It is proved from numerical comparisons that the method developed in the paper is reliable in predicting nonlinear behaviours of plates and shells.