Abstract
In two-dimensional elasto-plastic analysis by a finite element method, using a constant strain triangle, the obtained elastic-plastic boundary is affected remarkably by sizes and arrangement of elements and sometimes the elements with combining plastic and elastic elements appear intricately, the accuracy of the elastic-plastic boundary and the distribution of stresses of the part are aggravated. So, authors propose to determine a fair elastic-plastic boundary by using stresses at nodes, which are calculated from nodal-displacements and stiffness matrices of the related elements. It is shown an example of perforated strips under pure tension.
