A Unified Framework For Micromechanical Damage Modeling In Laminated Polymer Matrix Composites

Abstract

A unified numerical framework for progressive damage analysis in polymer matrix composite (PMC) laminates has been developed by explicitly accounting for damage progression at the micro-level. A three-dimensional repeating unit cell (3D-RUC) at the micro-scale considering plasticity-based matrix damage, maximum stress based fiber failure, and a traction separation based interface failure has been developed. Images of the micro-structure of unidirectional long fiber reinforced plastic (UD-FRP) laminates have been used to develop the random micro-structure for the 3D-RUC. Coupling of macro- and micro- levels has been accomplished using non-linear homogenization principles. User material models for up-scaling have been developed to capture the damage progression in a UD-FRP laminate off-axis to the tensile loading direction. In addition to incorporating constituent damage models in the 3D-RUC framework, the effects of spatial randomness in the micro-structure have been studied by modeling randomly distributed fibers (spatially) embedded in the matrix. Randomness in strength properties has also been incorporated using weakest link based Weibull statistics. Using varying strength properties along the fiber length enables capturing of multiple fragmentation of the fiber under tensile loading. Predictions from the current analysis have been compared with the response of a composite UD-FRP plate with a central hole under tensile loading. The numerical prediction was found to match well with the experimental data