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

Response of quasi-isotropic laminates of SiC coated Carbon/Carbon (C/C ) composites have been investigated under flexural loading at various temperatures. Variation 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 Micro scope (OM) and Non-Destructive Evaluation (NDE) have been performed to understand the failure mechanisms. Damage zone is found only within t he neighborhood of the loading plane. Isoparametric layered shell elem ents developed on the basis of the first order shear deformation theor y have been used to model the thin laminates of C/C under flexural loa ding. Large deformation behavior has been considered in the finite ele ment analysis to account for the non-linearities encountered during th e actual test. Data generated using finite element analysis are presen ted to corroborate the experimental findings, and a comparison in resp ect of displacement and stress-strain behavior are given to check the accuracy of the finite element analysis. Reasonable correlation betwee n the experimental and finite element results have been established.