Multi-Scale Fracture Mechanics of 3-D Reinforced Composites

The simply coupled scale analysis method SCSAM has been further extended to perform fracture analysis of heterogeneous materials and multilayered composite materials in particular, whereas previously we evaluated strength based on stress levels in undamaged composites. Progressive multicrack fracture simulation on each scale is performed by using the mesh-independent crack propagation technique and cohesive formulation for crack extension. A representative volume element RVE approach employed for homogenized stiffness and stress concentration factor computation was extended to compute homogenized cohesive crack opening relationship on the higher hierarchical scale based on the cohesive relationships of the constituents. In the spirit of SCSAM and within the limitation of sufficiently small microstructure scale simulation, the coupling of scales is occurring through hierarchical computation of homogenized properties, which now include fracture properties, whereas the simulation of the failure process on each scale is conducted independently. Such an approach is highly practical and applicable to prediction of complex phenomena in composite and hybrid materials.