Application of the energy-based criterion to the simulation of the fracture of the steel structures

Abstract

In this work we have developed energy balance model for inelastic deformation process of metals. Changes in the material structure are taking into account with the help of tensorial variable having the physical meaning of additional strain induced by initiation of defects. Introduction of such a parameter allows one to calculate the stored energy value and develop an energy-based fracture criterion. There were considered two ways of derivation of constitutive equations for plastic and structural strain. The first method was based on the principles of linear nonequilibrium thermodynamics, the second one is the analogue of the flow plastisity theory. Developed thermomechanical model includes equilibrium equation, geometric relation for strain tensor, Hooke’s law, constitutive equations for structural and plastic strain and energy balance equation. It is assumed that fracture in the material takes place when stored energy reaches critical value in some volume of the material. The application of such an approach to fracture problems of the metals is illustrated by two numerical examples. The first example is crack path simulation in the steel shaft with initial crack oriented at the certain angle to the shaft axis. The second example is simulation of the crack initiation and propagation in the steel bearing bracket. The obtained results are in agreement with the previously published results and could be used for simulation of fracture of real structures.

Keywords

• stored energy
• numerical simulation
• fracture of solids
• thermodynamics of inelastic deformation
• aisi 304 steel