Numerical Modeling of Crack Growth under Mixed-Mode Loading

Abdulnaser M. Alshoaibi

doi:10.3390/app11072975

Abstract

The aim of this paper is to simulate the propagation of linear elastic crack in 3D structures using the latest innovation developed using Ansys software, which is the Separating Morphing and Adaptive Remeshing Technology (SMART), in order to enable automatic remeshing during a simulation of fracture behaviors. The ANSYS Mechanical APDL 19.2 (Ansys, Inc., Canonsburg, PA, USA), is used by employing a special mechanism in ANSYS, which is the smart crack growth method, to accurately predict the crack propagation paths and associated stress intensity factors. For accurate prediction of the mixed-mode stress intensity factors (SIFs), the interaction integral technique has been employed. This approach is used for the prediction of the mixed-mode SIFs in the three-point bending beam, which has six different configurations: three configurations with holes, and the other three without holes involving the linear elastic fracture mechanics (LEFM) assumption. The results indicated that the growth of the crack was attracted to the hole and changes its trajectory to reach the hole or floats by the hole and grows when the hole is missing. For verification, the data available in the open literature on experimental crack path trajectories and stress intensity factors were compared with computational study results, and very good agreement was found.

Highlights

IntroductionWith regards to the ultimate load capability and progression of pre-existing cracks, computational methods are commonly used to assess the durability of cracked structures
This paper aims to study the effect of the crack tip location related to the presented holes in the trajectory of the crack propagation, stress intensity factors (SIFs), and fatigue life of a three-point-bending specimen with three holes and six different configurations using the XFEM implemented by ANSYS APDL 19.2
The results showed high sensitivity to small changes in the initial position in the crack path. This example has been commonly used to test the predictive ability of the system as a benchmark for numerical models

Summary

Introduction

With regards to the ultimate load capability and progression of pre-existing cracks, computational methods are commonly used to assess the durability of cracked structures. Many of the simulations frameworks available in the literature are utilized using extended finite element method (XFEM) because of its capability to simulate complicated components, providing accuracy in the estimation of interfacial parameters among various materials. Numerical analyses such as finite element analysis have become an incredibly useful method for modeling the propagation of a crack and for determining associated parameters such as the energy release rate and stress intensity factors (SIFs). New approaches and methods in several areas of study have been suggested and developed rapidly, including the FEM, Discrete Element Method (DEM) [1,2,3], Element Free Galerkin (EFG) method [4], XFEM [5,6,7], cohesive element method [8,9], and phase-field method [10]

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Results

Conclusion