ABSTRACT
Failure models are proposed to predict the mixed-mode fracture of notched composite laminates subjected to uniaxial and multiaxial loading. These failure models require basic elastic properties, strength properties and a characteristic length. This chapter shows that the notched strength of multidirectional laminates under multiaxial in-plane loading can be modeled in a compact-form solution, yet the accuracy is assured by a number of comparisons. The failure modes of composite laminates can generally be classified into fiber mode and matrix mode. The ultimate fracture of a multidirectional laminate which contains longitudinal plies with fibers in the principal loading directions is dominated by fibers. A characteristic damage zone is utilized to compute the stress concentration of the laminate, which is considered as an effective stress concentration at the final stage of the failure process. The effective stress concentration can be considered as a point parameter or average parameter (average over the characteristic length).
