A Design Oriented Approach to Creep and Plasticity in Finite Element Programs

This paper presents procedures for introducing plasticity and creep into finite element programs. The plasticity method described is intended for the designer who is interested in the stress distribution under prescribed loading conditions. The plasticity method uses a “relaxing approach” with initial strain equations. As a natural extension of the initial strain equations, creep is also presented. With both plasticity and creep available, a finite element program can be used to examine the stresses during the duty cycle of a piece of hardware. Examples of highly stressed turbine disks are shown.