Viscoelastic and Damage Analyses of Fibrous Polymer Laminates by Micro/meso-mechanical Modeling

Abstract

Micro/meso-mechanical models for unidirectional and angle-ply laminates under an off-axis tensile loading are presented. Three-dimensional unit/multi-cell representations of laminates with periodical fiber arrays are established. The matrix is described by a nonlinear viscoelastic model, and the fiber is described by an elastic one. Matrix cracking is modeled by the smeared crack method, which permits a crack description in terms of stress-strain relations and stiffness reduction in particular orientations. The modeling of material nonlinearity, damage initiation and growth, and the multiaxial loading with appropriate periodic boundary conditions are successfully incorporated in a FEM analysis. As examples of this unified analysis procedure, numerical results for unidirectional, angle-ply, and crossply laminates are presented. Using the same set of material constants of the constituents, different response characteristics of the three types of laminates are predicted, and the results are found to be in good agreement with the test data.