FE2 methodology for discrete cohesive crack propagation in heterogenous materials

To study the discrete crack growth of heterogeneous materials, a dual-scale discrete fracture calculation method is proposed in this paper. An equivalent cohesive energy criterion is proposed for the FE2 model based on the characteristics of the fracture zone. The representative volume element (RVE) with a cohesive zone is embedded into the Gauss points of the macro-element to replace the full FE model of the discrete crack. Therefore, the dual-scale method of discrete fractures not only improves the dual-scale modeling of discrete cracks but also greatly reduces the computational cost. We further demonstrate that the built-in capabilities of commercial software are naturally compatible with this method. Finally, the fracture process of a two-phase heterogeneous material containing a zirconium alloy matrix and hydride was studied using the dualscale method. The macro-fracture direction was related to the precipitation direction of the brittle hydrides. This conclusion is consistent with existing experimental observations.

Automated summary

A dual-scale discrete fracture calculation method is proposed to study the discrete crack growth of heterogeneous materials. By embedding a representative volume element (RVE) with a cohesive zone into the Gauss points of the macro-element, the full finite element model of the discrete crack is replaced, improving both the dual-scale modeling and reducing computational cost. The method is shown to be compatible with commercial software. The fracture process of a two-phase heterogeneous material is studied using this method, and the resulting macro-fracture direction is consistent with experimental observations.