Advanced fiber materials provide the highest specific strength and stiffness among engineering materials. Delamination fracture is the limiting factor for premature failure at loads much lower than the nominal fiber load-bearing capacity. Therefore, a better understanding of the mechanism associated with delamination fracture is beneficial. Here, a micromechanical model is proposed to determine the opening mode (Mode Ⅰ) delamination fracture toughness of a unidirectionally reinforced material. The relative importance of the matrix and the fiber-matrix interface as well as the effect of volume fraction on the delamination toughness is investigated.
