Cohesive Models for Anti-Plane Mode Fracture in Dissimilar Structures: Effect of Small/Large Scale Yielding Conditions on Computed Fracture Load

The study delves into the issue of anti-plane mode cracking in dissimilar structures, commonly encountered in welds, composites and functionally graded materials. Achieving an accurate representation of these structures involves acknowledging a gradual variation of elastic properties across interfaces, achieved by incorporating a non-homogeneous layer characterized by finite width and bounded variable elastic properties. The investigation builds upon a model previously developed employing a numerical solution to a singular integral equation using the Dugdale cohesive law. In this paper, a comparable model based on the finite element method, incorporating an implemented cohesive model is introduced. The primary focus is on calculating the fracture load, allowing for a subsequent comparative analysis of results. The ensuing discussion revolves around the calculated relative sizes of cohesive zones, considering the corresponding implications of small/large-scale yielding conditions. While both approaches yield sufficiently similar fracture load values for small cohesive zone sizes, noticeable scatter is observed in instances of larger cohesive zone sizes.