PSI - Issue 58

P.C. Sidharth et al. / Procedia Structural Integrity 58 (2024) 115–121 P.C. Sidharth and B.N. Rao / Structural Integrity Procedia 00 (2019) 000–000

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the x-axis and the crack positioned at either the ZrO2 edge (X1) or Al2O3 edge (X2), and similar configurations along the y-axis (Y1 and Y2). Load-deflection responses are assessed using both linear finite element (LFE) and exponential finite element (EFE) shape functions. In cases where material properties vary along the y-axis, the elastic and fracture characteristics remain consistent in the direction of the crack. However, this introduces mode mixity at the crack tip due to the material gradient. The load responses consistently demonstrate that higher values of the parameter "p" lead to increased stiffness and earlier fracture, which is in agreement with previous research. This behavior is anticipated because the material along the crack path has a higher "E" value but provides less resistance to fracture. In all four scenarios, the utilization of exponential finite element (EFE) shape functions consistently predicts higher peak load responses compared to linear finite element (LFE) predictions, while also achieving matching peak displacements.

Table 1. Material properties of alumina and zirconia

Al 2 O 3

ZrO 2 210 0.31

Young’s modulus, E (GPa)

380 0.26

Poisson’s ratio ν

5.2

9.6

Fracture toughness, K IC ( MPa m )

Fig. 2. Alumina/zirconia FG plate; Boundary conditions and crack propagation path for the specimen loaded in tension. The simulation uses adaptive mesh refinement scheme in MOOSE, where critical elements are refined automatically.