Damage assessment of thin SiC/SiC composite plates subjected to quasi-static indentation loading

Tri-dimensional woven SiC/SiC composite was subjected to quasi-static indentation tests at room temperature. For this purpose, hemispherical indentors and circular supports of various diameters were used. The extent of damage was evaluated with the help of optical and scanning electron microscopy. Formation of cone cracks initiating from the indented site is observed. The predominant internal damages (fibre bundle and matrix cracking) remain localised beneath the indentor. The indented specimens were tensile tested at room temperature to determine their residual strength. Results indicate that the strength reduction is proportional to the diameter of the damaged zone evaluated on the back side of the specimen.