三维结构安定分析的直接算法

A DIRECT ANALYSIS METHOD FOR SHAKEDOWN OF THREE-DIMENSIONAL STRUCTURES UNDER CYCLIC LOADING

基于线性随动强化理论和Von Mises屈服准则,对蒙板结构直接安定分析法进行了扩展,建立了结构的三维安定直接分析法.根据投射原理,推导出结构发生塑性安定的存在条件,便于调整控制加载步长和载荷历程.采用逐次增量加载方式,确定出背应力的偏移范围,克服了原始直接分析法不能获得安定极限的缺陷,并得到安定极限条件下结构中残余应力与应变的分布状况.该数值方法将弹塑性问题分解为弹性问题和特征应变决定的残余问题,节约计算时间,提高计算效率,将该算法应用于相关算例,并与有关数值结果相比较,验证了该算法的有效性.

A direct method for three-dimensional structures under cyclic loading was established based on elastic-linear-kinematic-hardening materials. An incremental loading method was adopted to construct loading space, and the range of back stress was bounded based on some research results. The direct method consists of an operator split technique, which transforms the elastic-plastic problem into a purely elastic problem and a residual problem with prescribed eigenstrains. The eigenstrains were determined using an in- cremental projection method. The residual stress and residual strain of structures under shakedown condi- tions were obtained. The direct method was further applied to rolling-sliding contact and three-dimensional holed plate, showing good agreement with some published results.