Effect of the Material Gradation on the Fracture Trajectory in Ceramic/Metal Functionally Graded Materials

Abstract

This paper is based on a 2D numerical study of crack initiation and growth in ceramic/metal functionally graded materials (FGMs) under mixed mode condition. The finite element method is used for modeling the crack growth trajectory. Two types of ceramic/metal FGMs are considered to explore the effect of the material gradation on the fracture trajectory. The variation of the material properties is declared in a program by defining the material parameters at the center of the elements. After a numerical evaluation of the fracture parameters, the Maximum Tangential Stress (MTS) criterion is used for the prediction of crack propagation direction with respect to the crack axis. The difference in the crack growth trajectory can be related to the influence of the material gradient. In addition, it was found that the easiest way for the crack propagation is when the crack is perpendicular to the material gradation. A crack located on the rigid side of the specimen deviates less compared to the one on the soft side.

Keywords

• mixed mode loading
• functionally graded materials
• stress intensity factors
• t-stress
• crack propagation
• ceramic/metal fgm