A comparison of calculated and measured debond lengths from fiber push-out tests

A procedure involving iterative finite-element analyses has been developed for the accurate prediction of the debond length as a function of force by using the progessive debonding load/deflection data from fiber push-out tests conducted on a polyester/epoxy model composite with a thickness of approximately 2.5 fiber diameters. The finite-element simulation included loads due to chemical shrinkage of the matrix during cure as well as the boundary conditions corresponding to the exact probe and sample support dimensions. The resulting debond lengths corresponded to within 7% of the measured debond lengths. Fracture energy was also determined by the finite-element method by computing the change in potential energy when incrementing the interface crack length by 0.1% of the total crack length and substracting the increase in the energy dissipated by friction.