Abstract
An a posteriori error estimation method for the finite element solutions of two-dimensional elasto-plastic problems is proceeded based on the theory of element-wise error analysis in two and three dimensional elastical problems developed by the authors. The error is estimated element by element with an 8-node element and the finite element elasto-plastic solution is modified after getting the error force of FEM for each element with considering the continuity of stresses on the node which connects the adjacent elements. A special technique is presented to carry out the error modifying procedures after each increment step including loading and unloading steps. The unequilibrium of applied error force for each element is overcome with adding two low stiffness spring elements to each node of the element. The error energy norm and its distribution are obtained, and a very accurate stress solution compared with the 8-node results of FEM is gotten by acting estimated error force to each element in two numerical models.
