Modeling of damage evaluation and failure of laminated composite materials across length scales

Abstract This chapter focuses on damage accumulation and failure in composite laminates across length scales. Modeling of the damage-accumulation process occurs on two different scales—the microstructural level (microscale) when modeling the damage, stiffness degradation, and failure of a unidirectional ply, and the ply level (macroscale) when analyzing the progressive failure of a composite laminate subjected to in-plane loading. A kinetic model is used to describe the failure progression of a unidirectional ply and its layered structure during the stages prior to the appearance of transverse cracks in the layers. This model accounts for two parallel processes: growth in the number of existing microdefects (e.g., fiber breakage, interfacial cracks at fiber bundles, transverse microcracks initiated by broken fibers, and longitudinal microcracks), and the generation of new microdefects. Continuum damage mechanics are used to model damage initiation, damage development, and stiffness degradation in composite laminates.