A Ductile Fracture Phase Field Model Based on Strain Rate‐Dependent Fracture Toughness

Abstract

The numerical simulation of ductile fracture failure plays an important role in the evaluation of the integrity of engineering structures with the development of computing science and technology. As a competitive approach to predict fractures, the phase field model has been developed for about two decades to deal with a variety of crack growth problems. Rate‐dependent fracture is an important research interest, and some studies have begun to focus on using phase field method to predict rate‐dependent fracture. Such as coupling viscous material constitutive with phase field or defining a rate‐dependent fracture toughness within the framework of phase field models. In this paper, a ductile fracture phase field model based on strain rate‐dependent fracture toughness is presented to describe the rate‐dependent mechanical response in elastoplastic materials such as metallic alloys. The fracture toughness is defined as a power function of the plastic strain rates, which can make a more flexible control of the rate‐dependent behavior of ductile fracture compared with the existing phase field methods. Additionally, a total energy density threshold is introduced to ensure a real stress‐strain response of elastoplastic materials prior to crack growth. Several numerical examples are conducted to illustrate the effectiveness of this model.