基于软化本构的有限元强度折减法

FINITE ELEMENT METHOD OF STRENGTH REDUCTION WITH SOFTENING CONSTITUTIVE MODEL

针对目前有限元强度折减法每次计算均从零应力状态算起,需要大量试算的缺点,提出基于软化本构的有限元强度折减法。该方法仅需一次性施加所有外力,通过折减系数的增量迭代来使边坡进入极限平衡状态。该方法直接模拟强度折减过程,在此过程中,屈服面会不断地收缩,通过应力跌落和塑性流动来调整各高斯点的应力值来使系统达到平衡,直至系统进入极限平衡为止。最后给出2个算例验证了本文方法的可靠性。

A new iteration method with the softening constitutive model is proposed to overcome the shortcomings of the existing method of strength reduction in FEM that every computational process started from the zero stress state. In the new method, the strength reduction factor to bring slope into the limit equilibrium state after all the external loads applied was increased gradually. The method directly simulated the process of strength reduction. During the process of the yielding surface shrinking, the stresses at each Gauss＇ point reached the equilibrium state through stress drop and plastic flow. Two examples are given to prove the effectiveness of the method.