Experimental evaluation and theoretical prediction of elastic properties and failure of C/C-SiC composite

The paper presents experimental characterization and theoretical predictions of elastic and failure properties of continuous carbon fiber reinforced silicon carbide (C/C-SiC) composite fabricated by Liquid Silicon Infiltration (LSI). Its mechanical properties were determined under uniaxial tensile, compression, and pure shear loads in two sets of principal coordinate systems, 0°–90° and ±45°, respectively. The properties measured in the 0°–90° coordinate system were employed as the input data to predict their counterparts in the ±45° coordinate system. Through coordinate transformations of stress and strain tensors, the elastic constants and stress-strain behaviors were predicted and found to be in good agreement with the experimental results. In the same way, three different failure criteria, maximum stress, Tsai-Wu, and maximum strain, have been selected for the evaluation of the failure of C/C-SiC as a type of genuinely orthotropic material. Based on the comparisons with experimental results, supported by necessary practical justifications, the Tsai-Wu criterion was found to offer a reasonable prediction of the strengths, which can be assisted by the maximum stress criterion to obtain an indicative prediction of the respective failure modes