Experimental study of tensile properties and deformation evolutions of 2D and 2.5D woven SiO_2f/SiO_2 composites using single-camera stereo-digital image correlation

摘要

SiO2f/SiO2 composites have become a promising candidate material for thermal protection systems due to its unique combination of various properties such as low density, high thermal shock resistance, favorable electrical insulating properties and enhanced mechanical properties. The increasing interests in these materials lead to a pressing requirement on comprehensively understanding their mechanical behaviors and load bearing mechanisms under external loads. The present work focuses on experimental study and comparison of the mechanical properties and deformation evolutions of 2D and 2.5D woven SiO2f/SiO2 composites using single-camera stereo-digital image correlation (stereo-DIC) technique. Based on the full-field displacements and strains retrieved by single-camera stereo-DIC, the mechanical properties of 2D and 2.5D woven SiO2f/SiO2 composites can be determined. It is found that 2D woven SiO2f/SiO2 composites present a lower yield strength and elastic modulus than 2.5D SiO2f/SiO2 composites. Also, remarkable differences in full-field displacement and strain distributions of the 2D and 2.5D SiO2f/SiO2 composites are observed, indicating a strong influence of the weave architecture on the deformation evolution and load bearing mechanism of SiO2f/SiO2 composites. Finally, the failure mechanisms of these two composites are discussed.