Investigation of continuum damage mechanics model without element size sensitivity

Abstract

A discontinuous material behavior such as ductile fracture and fatigue failure is predicted actively in various fields by FEM. There is continuum damage mechanics as a method to evaluate the discontinuous material behavior in a framework of continuum mechanics. However, the predicted behavior based on the method depends strongly on finite element size. Then, improvement of damage evolution equation and damage limit equation in continuum damage mechanics is discussed to reduce the mesh-dependence. These equations are extended based on finite element size and evaluated strain gradient. The predicted material property such as fracture strain in tensile test based on new equations corresponds to experimental result. Additionally, the prediction accuracy is higher than conventional mesh-independence model. Especially, the higher the tensile strength of material is, the higher the prediction accuracy is.