Certification Modeling for Composites with Voids and Wrinkles for Engines and Structures

This proposal aims at developing a material agnostic modeling and analysis capability to help understand the genesis of voids and wrinkles during the processing and curing of fibrous composites. It also develops a hierarchical framework to investigate the effects of these micromechanics defects on the interlaminar strength and fatigue life of curved composite structures. The overall effort is categorized into three parts: (i) Process Modeling part that deals with the initial transient phase until the cure cycle is completed, (ii) Performance Modeling part that investigates the fatigue integrity of composites with embedded voids and wrinkles, and (iii) Experimental Program on CT imaging and microscopy, that are applied in novel way to extract porosity data at early stage, and fatigues testing with wrinkled specimens along with DIC to extract residual interlaminar properties. Process modeling employs a two-pronged approach: A discrete micro-level (fiber-matrix level) approach, and a locally-homogenized macro-level (ply level) approach. A unique feature of our computational method is seamless and uniform coupling of the various hierarchical models in a variationally consistent fashion. A combined modeling, analysis and experimental validation program will help with the calibration of theoretical and computational models as well as for sensitivity analysis of modeling parameters.