Multiscale Approach to Damage Analysis of Laminated Composite Structures

The presented work depicts results of a two-scale approach to the problem of damage and failure prediction on laminated composite structures. Modeling on the micro-level has enabled insight into the underlying physical processes which lead to homogenized properties of the macro-scale material. In this work, micromechanical analysis has been performed by application of the High Fidelity Generalized Method of Cells theory (HFGMC), which is implemented into Abaqus via user material subroutine VUMAT. As result of the HFGMC analysis, micromechanical strain concentration tensors, which relate the strain tensor on the macro-level to the strain tensors of each subcell, have been computed. This enabled calculation of the stress field within the unit cell, based on the constitutive behavior of each subcell. The first stage of modeling damage prediction in composite structures is application of failure criteria in order to account for damage initiation. This work shows results of the application of the most commonly used micromechanical failure criteria applied for unidirectional composites. The micromechanical failure criteria have been compared to the failure criteria applied at lamina (macro) level. The structural model at the macro-scale is a stiffened composite panel, commonly used in aircraft structures.