A Numerical Modelling of Mixed Mode Crack Initiation and Growth in Functionally Graded Materials

Abstract

The main objective of this work is to present a numerical modeling of crack propagation path in isotropic functionally graded materials (FGMs) under mixed-mode loadings. The displacement extrapolation technique (DET) and the maximum circumferential stress (MCS) criterion are investigated in the context of crack growth in functionally graded beam subject to three and four bending conditions. Using the Ansys Parametric Design Language (APDL), the variation continues of the material properties are incorporated by specifying the material parameters at the centroid of each finite element (FE) and the crack direction angle is evaluated as a function of stress intensity factors (SIFs) at each increment of crack extension. In this paper, two applications are investigated using an initial crack perpendicular and parallel to material gradient, respectively. The developed approach is validated using available numerical and experimental results reported in the literature.

Keywords

• Functionally graded materials
• Stress intensity factor
• Displacement extrapolation
• Crack propagation
• Mixed mode