Experimental study on effect of fiber angel orientation and mixed-mode ratio on fracture toughness of fiber reinforced laminate

The effects of fiber angel orientation and mixed-mode ratio of interlaminar fracture on the properties of delamination were experimentally studied in the laminate propogates. The results show that 0°ply is able to stop delaminating from jumping into adjacent plies in mode Ⅰ interlaminar fracture; fracture toughness of unidirectional laminate at all mixed-mode ratios could be regarded as the conservative value; the curve of mixed-mode fracture toughness resembles sine as the mixed-mode ratio varies.