Failure Initiation Predictors for Reliability-Based Design of Hybrid Composite Materials

This proposal is concerned with the development of a novel failure initiation and progressive failure analysis (PFA) modeling method for advanced composite structures. The laminate is modeled as a collection of degrading lamina within the framework of lamination theory and executed using user defined subroutines through a commercial finite element software package. In the proposed approach, designated as “progressive failure analysis tool”, (PFAT), computations will be simultaneously carried out in parallel at three length scales, as needed (the laminate level (LAM), the lamina level (LL) and at the level of a fiber/matrix (FM) unit cell representation of the lamina), with strong coupling between the three scales. The results to be obtained will provide the necessary guidance in selecting the most robust methodology to achieve the desired goal of combining initial design with reliability based tools to re-design a composite structure. The proposal utilizes a fundamental physics based approach that is devoid of empirical formulas that have dominated failure prediction tools in composites.