A meso-scale simulation framework for predicting the mechanical response of triaxial braided composites

In this paper, we propose a novel simulation framework for accurately predicting the mechanical response of highly compacted triaxial braided composites using meso-scale finite element models. Unit cells with a realistic internal geometry are generated within an automated simulation work-flow. Local volumetric interpenetrations are removed from a nominal geometry in a fictitious thermal simulation step. A compaction simulation of a single textile layer is performed to the desired target fibre volume fraction while implicitly considering multiple plies in different nesting configurations through periodic boundary conditions. For mechanical simulation, a matrix pocket mesh is created from a reconstruction of the deformed textile. A novel meshing methodology incorporates branching cohesive yarn-to-yarn and yarn-to matrix interfaces for modelling delamination. The framework was validated by detailed comparison with experimental results for three braid architectures. The excellent correlation of the internal geometry and the elastic properties underlines the framework's potential for future damage modelling.