A Combined Experimental and Finite Element Study to Predict the Failure Mechanisms in SiC Coated Carbon/Carbon Composites at Room and Elevated Temperatures under Flexural Loading

Abstract

Response of quasi-isotropic laminates of SiC coated Carbon/Carbon (C/C) composites have been investigated under flexural loading at various temperatures. Varia tion of load-deflection behavior with temperatures are studied. Increase in flexural strength and stiffness are observed with the rise in temperature. Extensive analyses through Optical Microscope (OM) and Non-Destructive Evaluation (NDE) have been per formed to understand the failure mechanisms. Damage zone is found only within the neighborhood of the loading plane. Isoparametric layered shell elements developed on the basis of the first order shear deformation theory have been used to model the thin lami nates of C/C under flexural loading. Large deformation behavior has been considered in the finite element analysis to account for the non-linearities encountered during the actual test. Data generated using finite element analysis are presented to corroborate the ex perimental findings, and a comparison in respect of displacement and stress-stram be havior are given to check the accuracy of the finite element analysis. Reasonable correla tion between the experimental and finite element results have been established.

Evaluation of dynamic modulus measurement for C/C‐SiC composites at different temperatures

“…Therefore, RFDA turns out to be a beneficial experimental procedure as both, room temperature and high temperature measurements can be performed under specific atmospheric conditions. 8,16,[19][20][21] Different to quasi-static mechanical testing the RFDA method by IMCE (Integrated Material Control Engineering, Belgium) applied at the Institute of Mineral Engineering of the RWTH Aachen is of great advantage for analyzing the flexural modulus at high temperatures. Their lower density compared to metallic alloy used for high temperature application is also a key advantage.…”

“…Therefore publications about flexural modulus characterization via quasi-static method at high temperatures are rare. 8,16,[19][20][21] Different to quasi-static mechanical testing the RFDA method by IMCE (Integrated Material Control Engineering, Belgium) applied at the Institute of Mineral Engineering of the RWTH Aachen is of great advantage for analyzing the flexural modulus at high temperatures. With densities of about 1.9-2.0 g/cm 3 C/C-SiC composites 8 are suitable for the RFDA method as these densities allow a local impulse excitation with low damping and without a global shift of the sample.…”