Application of Virtual Crack Close Technique in the Static Crack Growth Based on Strain Energy Release Rate Criterion

A method to simulate the crack growth, according to the strain energy release rate criterion, with the virtual crack close technique, is studied. The virtual crack close technique is used to calculate the strain energy release rate. To achieve the virtual crack close technique, in the FEA software of ANSYS, COMBIN14 spring elements are adopted to set up the finite element model. Then this method to simulate the crack growth is validated by three crack growth problems. This method is a useful and accurate numerical simulation method.

3D-DDM Simulation of Crack Propagation of Non-Linear Deformation Structural Plane

Structural plane is different from common crack, as it is often under pressure and has non-linear normal and tangential deformation behavior. This paper simulates the propagation of non-linear deformation structural plane by 3D displacement discontinuity method (DDM). Through least square regression of the elements near the tip, the stress intensity factor (SIF) of the tip is obtained. Maximum energy release rate criterion is adopted to be the fracture criterion in this paper, assuming the propagation occurred in the normal plane of the front edge, KI is modified to consider the effect of mode Ⅲ crack. The structural plane model is considered as a hyperbolic non-linear model, the Barton-Bandis model is adopted as the normal deformation model, the Kulhaway model is adopted as the tangential deformation model, and the Mohr-Coulomb criterion is adopted as the shear strength criterion. The result shows that the propagation direction is along the direction of the load, DDM could efficiently trace this process.

ON THE INVISCID LIMIT OF A MODEL FOR CRACK PROPAGATION

We study the evolution of a single crack in an elastic body and assume that the crack path is known in advance. The motion of the crack tip is modeled as a rate-independent process on the basis of Griffith's local energy release rate criterion. According to this criterion, the system may stay in a local minimum before it performs a jump. The goal of this paper is to prove the existence of such an evolution and to shed light on the discrepancy between the local energy release rate criterion and models which are based on a global stability criterion (as for example the Francfort/Marigo model). We construct solutions to the local model via the vanishing viscosity method and compare different notions of weak, local and global solutions.