求解预定位移水平的改进弧长法

An improved arc-length method for searching pre-defined displacement in nonlinear analysis of structures

为了在使用弧长法进行结构非线性分析时能够收敛到指定的位移,基于广义弧长的概念,对传统弧长法进行改进。改进后的方法不仅能够自动跟踪结构非线性平衡路径,同时能求得位于结构平衡路径的任意区段的任意预定位移时的受力状态。数值算例表明本文计算方法的精确度、效率以及可靠性较好。

Arc-length method is widely employed in nonlinear FEM analysis because it is efficient and robust for solving the nonlinear formulation, especially for the problem of Snap-through and Snap-back. But it is rather difficult to converge to a specified displacement level with this method. Based on the concept of generalized arc-length, an improved arc-length method is presented to converge to pre-defined displacement. The improved method can be used to search and determine the pre-defined displacement levels besides tracing the whole nonlinear equilibrium path of a structure. Numerical experiment shows that the new method is accurate, efficient and reliable.