Tow waviness and anisotropy effects on Mode II fracture of triaxially woven composite

Mode II fracture toughness, <i>K</i>_IIC, of single-ply triaxially woven fabric (TWF) composite due to tow waviness and anisotropy effects were numerically and experimentally studied. The numerical wavy beam network model with anisotropic material description denoted as TWF anisotropic was first validated with experimental Mode II fracture toughness test employing the modified compact tensile shear specimen configuration. 2D planar Kagome and TWF isotropic models were additionally constructed for various relative densities, crack lengths, and cell size parameters for examining effects due to tow waviness and anisotropy. <i>K</i>_IIC generally increased with relative density, the inverse of cell size, and crack length. It was found that both the waviness and anisotropy of tow inflict a drop in <i>K</i>_IIC of TWF. These effects were more adverse due to the waviness of tow compared to anisotropy.