| About this Abstract |
| Meeting |
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
| Symposium
|
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
| Presentation Title |
Coupled Oxidation and Damage Model for SiC/SiC Ceramic Matrix Composites |
| Author(s) |
Mohamed H. Hamza, Jacob J. Schichtel, Aditi Chattopadhyay |
| On-Site Speaker (Planned) |
Mohamed H. Hamza |
| Abstract Scope |
A multiphysics oxidation and damage model is proposed to capture the thermomechanical oxidative degradation of high temperature ceramics matrix composites (CMCs). Manufacturing induced microstructural defects such as matrix microcracks and porosity provide diffusion pathways for oxidizing species to ingress into the CMC interior and react with its constituents, hence degrading the stiffness of the material. Silicon carbide (SiC)-based matrix reinforced SiC fiber (SiC/SiC) CMCs are experiencing anomalous thermomechanical behavior at intermediate and high temperatures (≥1200°C). At high temperatures, SiC matrix oxidizes and forms a molten oxide ceramics, SiO2, also known as silica, which results in sealing of matrix microcracks. However, at intermediate temperatures, matrix oxidation does not occur, hence exposing the matrix/fiber interphase and fibers to oxidative degradation, where the growth of silica scale on the fiber surface induces significant loss in fiber strength. To tackle such complex mechanisms, the chemical reactions between oxygen and matrix/fibers are modeled through conservation of mass equations along with modified Fick’s law to govern oxygen, SiC and silica normalized concentrations evolution. The kinetic theory of gases is used to compute the oxygen diffusivity in a crack channel, while the effective oxygen diffusivity is modeled as a function of matrix damage and the normalized concentrations. The Galerkin method of weighted residuals is used to derive the weak forms of the equilibrium and conservation of mass equations, which are discretized for finite element method numerical implementation. Finally, the model is tested on high-fidelity stochastic representative volume element to comprehensively investigate the oxidative degradation and healing mechanisms. |
| Proceedings Inclusion? |
Definite: Post-meeting proceedings |