Multiscale approach to predict crack initiation in unidirectional off-axis laminates

Abstract

AbstractCrack initiation in unidirectional off-axis laminates made of carbon fiber and epoxy resin is predicted based on multiscale modeling. This multiscale modeling consists of two finite-element analyses (FEA) on different scales. One is macroscopic FEA, based on the assumption of homogeneous materials, and the other is microscopic periodic unit-cell (PUC) analysis using a micromechanical model. The macroscopic FEA is performed by applying uniaxial tension to off-axis laminates, in which we employ an anisotropic elasto-plastic constitutive law to obtain accurate deformation fields in laminates. In the microscopic PUC analysis, the strain history at a point in laminates obtained from the macroscopic FEA is applied as external forces, and crack initiation is predicted using two failure criteria for the matrix resin. The first is the dilatational energy density criterion under elastic deformation, and the second is a ductile damage growth law under plastic deformation. The simulated predictions are compared with the experiments results.Keywords: composite materialscrack initiationmultiscale modelingdilatational energy densityductile damage growth AcknowledgmentsT.O. thanks Toray Industries, Inc. and Toray Composites (America), Inc. for support of this study.