Abstract
Fiber-reinforced polymer matrix composites are fractured by accumulation of microscopic damage in fiber length scale. Therefore, accurate prediction of microscopic crack initiation is extremely important to predict failure of composite structures. In this study, multiscale modeling approach that consists of a macroscopic scale analysis and a microscopic scale analysis is proposed, and is applied to tensile testing of unidirectional off-axis specimens of carbon fiber reinforced plastic (CFRP) to predict their failure strain. On a macroscopic analysis, off-axis specimen is modeled as a homogeneous body, and 3D finite element analyses (FEA) are performed using an anisotropic elastoplastic constitutive law to obtain accurate deformation field under off-axis loading. On a microscopic scale, 3D periodic unit cell (PUC) analyses are conducted by applying strain history obtained from macroscopic FEA to predict initial cracking strain. Two failure criteria are employed for matrix resin in PUC analysis. The first is the dilatational energy density criterion for brittle failure, and the second is the ductile damage growth law for ductile failure. In order to validate the accuracy of proposed multiscale approach, predicted results are compared with the experimental results.
