Studies on Crack Propagation of Carbon Fiber Reinforced Epoxy Resin Composite

Abstract

Unidirectional carbon fibre reinforced resin matrix composite (CFRP) with different fibre volume fraction are stretched dynamically under static load in SEM, initiation and propagation mechanism of crack is in-situ observed, and tensile fracture of specimens is also observed. The results show that: Microscopic cracks are mainly originated from fracture of fibre, numerous fibre cracks transfixion each other in form of matrix or interface cracking, and cause failure of CFRP. Microscopic crack propagation path is related to the thickness of matrix layer between fibres. Propagation of single fibre crack at interface accord with description of microscopic crack deflection criterion for fibre reinforced composite, but the crack deflection criterion cannot descript microscopic crack propagation mechanism of unidirectional CFRP effectively, because distribution discreteness of fibre and its strength are not considered.