Damage model for FRP laminates with matrix microcracks and delamination
Bai QS; Murakami Sumio; Kanagawa Yasushi; Tanaka Kohhei
Abstract:A damage model for fiber-reinforced plastics (FRP) laminates with matrix microcracks and delamination is developed based on continuum damage mechanics (CDM) and modified lamination theory. The anisotropic damage state in each lamina due to matrix microcracks and the delaminations at each interface are described by different damage variables of second rank tensor. The elastic constitutive relations of matrix damaged laminae are derived first by use of the effective stress and the hypothesis of strain equivalence. Then the constitutive relation of each lamina is introduced into the modified lamination theory incorporating the effect of delamination. The resulting model is applied to CFRP angle-ply laminates, and both damage variables are identified by the measured densities of matrix cracks and delaminations, respectively. Comparison between the predictions and the experimental measurements shows the applicability of the present model to describe the influence of matrix cracks and delamination on the mechanical properties of angle-ply CFRP laminates. Key Words:FRP, composite, matrix crack, delamination, continuum damage mechanics, lamination theory, damage variable, anisotropic damage, interlaminar shear, stiffness reduction