The fracture toughness for first matrix cracking of a unidirectionally reinforced carbon/carbon composite material

Abstract

The fracture toughness for first matrix cracking of a uniaxially reinforced C-fiber/C-matrix composite is investigated using a modified controlled surface flaw method. The theoretical models for first matrix cracking of brittle matrix composites including the stress intensity and the potential energy approaches are reviewed in the light of the experimental results. The sharing of the applied load between the reinforcing fibers and the brittle matrix along with extensive crack front debonding enhance the fracture toughness for first matrix cracking.