Integrated FE-based Framework for High-fidelity Stochastic Progressive Failure Analysis of Composite Structures

The design and certification process of aerospace and automotive composite structures can be time-consuming and costly. Thousands of physical tests are required to obtain design allowables. Usually, the specimen configurations are limited to a few stacking sequences and geometric parameters. To reduce the number of physical tests and to explore a broader design space, the industry desires a virtual tool that can reliably predict the failure of arbitrary laminate configurations. In this presentation, we will demonstrate a finite element (FE) - based framework to perform integrated cure and progressive failure analyses of fiber-reinforced polymers. Developed as a plug-in for SIMULIA Abaqus, this framework goes beyond the micro-scale fiber-matrix unit cell to composite laminates at the macro-scale with various layups, geometries, and loading cases. First, cure-induced residual stresses are calculated using a coupled chemo-thermo-mechanical analysis. The cure-hardening instantaneous linear elastic (CHILE) constitutive model is used to model the hardening evolution of the matrix. After the residual stresses and deformed geometry are obtained at the end of the curing process, a progressive failure analysis (PFA) step is performed. The high fidelity and computationally efficient FE framework for PFA is based on a semi-discrete modeling approach, which is a good compromise between continuum and discrete methods. The enhanced semi-discrete damage model (ESD2M) toolset comprises a smart meshing strategy with failure mode separation, a new version of the enhanced Schapery theory with a novel generalized mixed-mode law, and a novel probabilistic modeling strategy. These three combined elements make our computational tool efficient in accurately capturing failure modes such as matrix cracks, fiber tensile failure, and delamination. The presented framework efficiently integrates failure mode predictions with probabilistic modeling and enables Monte Carlo simulations to predict the ultimate failure strength and its scatter. We will demonstrate our model’s capabilities using various test cases: Unnotched tension/compression, open-hole tension/compression, single-edge notched and center notched tension.