Failure analysis of 3D stitched composite using multi-scale approach for aerospace structures

Finite element modeling is an excellent technique for simulating a stitched woven composite to determine its mechanical properties and the analysis of the damage progress. In this technique, actual textile tow geometry measurements based on textile fiber photomicrographs are used to make the internal geometry of the fabric. In this paper, a unit-cell of the stitched composite was generated in micro and mesoscale geometric in the first step, and afterward, unit-cell was imported to finite element analysis software. Besides, a code for calculating the mechanical coefficient of the stitched composite was implemented in the micro and meso models. Finally, a user-defined subroutine implements the damage model in the finite element code to predict damage initiation of the stitched composite. The results of finite element modeling indicate a good agreement between experimental results and theoretical results. The finding of this research will contribute to the investigation of the integrity and damage tolerance of the 3 D stitched composite materials. It is able to assist in the certification of a modern aircraft made of stitched composites.