Three-Dimensional Inelastic Stress Analysis of Center Notched Composite Laminates with Damage

In this paper, a constitutive model for characterization of mechanical response in inelastic composite materials due to damage developed recently by the authors is first outlined. The formulation is based on the concept of damage surface and on the assumption that the change of material behavior is independent of loading path over which the damage state of material develops, but is dependent on the current stress state and the energy dissipated. The method is applied to describe the behaviors of graphite fiber reinforced composite laminates containing a small hole. The elastic-damaged response of interlaminar stresses in the composite laminates due to uniaxial tension is investigated with the aid of displacement-based finite element method. The initiation and development of damage zones in the laminates are examined using a three-dimensional analysis. The results of interlaminar stress distributions of the composite laminates analyzed with and without taking material stiffness degradation into account under the same external loading condition are presented and discussed.