Damage characterization of high velocity impact in curved SiC/SiC composites

Two-dimensional woven melt-infiltrated SiC/SiC curved composites (c-coupons) of the same thickness, but varying width were impacted at ambient temperature by high speed steel projectiles with velocities ranging from ~260 m/s to ~360 m/s. The undamaged arms of the c-coupons were removed to provide a straight specimen to impact in order to understand the effect of curvature on impact damage morphology. The post-impacted specimens were analyzed using non-destructive evaluation (NDE) methods such as electrical resistance (ER) and micro-computed tomography (micro-CT). Finally, the specimens were cut, polished, and the damage was further analyzed under an optical microscope. Ultimately, the straight specimens (arms) accumulated significantly more internal damage in the form of matrix cracking, delamination of fiber plies, and fiber fracture than their curved (c-coupon) counterpart as evident from ER, micro-CT imaging, and optical microscopy. Results also indicate a damage dependence upon the volume of the sample as the specimens with a greater volume suffered less damage than specimens with a smaller volume. © 2017 The American Ceramic Society.