Comparison of a viscoelastic frictional interface theory with a kinetic crack growth theory in unidirectional composites

In this paper we compare a frictional interface theory for fiber and matrix load sharing with a kinetic crack growth theory as applicable to the failure of unidirectional composites. First we formulate the creep lifetime prediction based on the viscoelastic frictional interface theory, and then we determine a parameter in the kinetic crack growth theory by fitting it to the frictional interface theory in terms of the creep lifetime prediction. Times-to-failure under a constant strain rate condition are then derived by these two models, and they are compared. The residual strengths after interrupted loading are also compared.