Finite Element Modeling Based on Composite Damage Theory or he Strength Prediction of 3D Braided Composites Structures

摘要

Finite element analysis for the strength prediction of 3D braided composites structures are presented in this paper. A strength analysis model was established to investigate the strength characteristics of the 3D braided composites. Repeated unit-cell (RUC) model was used in this model to describe the microstructure of 3D braided composites and differences between yarn configurations in corner, surface and interior RUCs were considered. Composite damage model were introduced into the yarns of the RUCs in the analysis model and the macroscopic failure and damage evolution of the 3D braided composites structures were characterized by the damage of yarns by nonlinear homogenization method. To validate the veracity of this model, a user defined material subroutine (UMAT) was developed to introduce this model into the finite element analysis software and the damage progression of a 3D braided composite structure under three-point bending was simulated. Good agreements were achieved in the load-deflection curves and damage morphology between experimental and numerical results.