Session: 03-10-02: Micromechanics and Multiscale Modeling

Paper Number: 162028

162028 - Coupled Oxidation and Viscoplastic Model for Analyzing Thermomechanical Performance of Ceramic Matrix Composite Microstructures 

A coupled multiphysics oxidation and viscoplastic model is developed to investigate the impact of life-limiting oxidative degradation mechanisms and thermally activated creep processes on the time-dependent response of SiC_f/SiC ceramic matrix composite (CMC) microstructures. The methodology is derived from the governing equations for force equilibrium and conservation of mass, which are coupled through chemical reaction terms, matrix damage, oxygen diffusivity, and solubility to address the spatiotemporal response of heterogeneous CMC microstructures at elevated temperatures. The silica formation and growth kinetics at the SiC fiber surfaces are modeled explicitly, and the impact of matrix damage on the rate of oxygen ingress, as well as the stresses and damage induced by the SiC-silica phase transformation, are investigated. A three-dimensional viscoplastic constitutive model, based on Hill’s orthotropic plastic potential, an associative flow rule, and the Norton-Bailey creep law with Arrhenius temperature dependence, is used. The methodology provides important insights into fiber/matrix load transfer mechanisms due to the combined effects of oxidation damage and constituents’ creep. The Galerkin method of weighted residuals is used to derive the weak forms of the equilibrium and conservation of mass equations, which are then discretized for numerical implementation using the finite element method. Finally, the model is tested on high-fidelity microscale stochastic representative volume elements that account for the inherent flaws in the CMC microstructures.

Presenting Author: Mohamed Hamza Arizona State University

Presenting Author Biography: Mohamed H. Hamza is a Postdoctoral Research Scholar at the Adaptive Intelligent Materials & Systems (AIMS) Center, Arizona State University. He has recently got his PhD in Mechanical Engineering, Arizona State University, and he has a Master of science in Engineering degree from the Mechanical Engineering Department, Johns Hopkins University. His research expertise is in computational mechanics and machine learning. The current main research focus includes: i) Multiphysics modeling of ceramic matrix composite (CMC) deformation and damage behavior in extreme environment; ii) Physics-informed machine learning-based surrogate models for CMC microstructure time-dependent response; iii) Generative deep learning algorithms for high-fidelity micromechanics simulations and materials discovery; iv) Physics-informed surrogate models for aircraft trajectory prediction and aviation risk region assessment.