A micro-macromechanical approach for composite laminates

Abstract

The calibration of a general model for composite materials and its application to the case of fiber reinforced composite laminates are presented in this paper. The constitutive equation for the composite results from the combination of the constitutive equations of the laminae that, in turn, are obtained from the combination of fibers and matrix. The behavior of each component is simulated by a general elastoplastic anisotropic model. The combination rules obey to the microstructure of the composite. In order to calibrate the general model, the behavior of composites formed by laminae reinforced with unidirectional fibers is studied. Three-dimensional finite element models are used to study the distribution of stresses and strains inside the composite. These finite element models are useful to verify the hypotheses of the proposed composites theory, in a relatively simple way. Comparisons between elastic properties of laminae obtained with the finite elements model, with Mori-Tanaka method, with the model for composite studied and experimental results are included in the paper. Elastic properties of laminates with different stacking sequences and fibers orientations are also obtained. Additionally, application examples showing the non-linear response of laminae and laminates obtained with the calibrated model and comparisons with experimental results are presented. The results show that the calibrated model describes the behavior up to failure of composite laminates. The failure mode of the composite produced by the failure of one or more of its components can be identified. The calibrated model is also able to reproduce complex failure modes that change from the matrix to the fibers depending on the type of stress state. © 2008 Elsevier Ltd. All rights reserved.