"Single" fragmentation of a porous SiC by nEOI

Ceramic materials are being more and more used in bi-layer shielding solutions. When impacted, substantial tensile damage creates within the ceramic tile that manifests as numerous oriented cracks. Understanding the dynamic fracture response under high strain-rates and at the level of a single dynamic crack is of major importance in pushing forward the design of resilient ceramic-based armour solutions. Single fragmentation of brittle materials in dynamic is possible with adapted experimental techniques. For that, one of these methods is the notched-Edge-On-Impact (nEOI). This experimental method enables the study of a single quasi-straight dynamic crack which propagates through a single-notched rectangular specimen. When the projectile impacts the specimen, a compressive pulse propagates and reflects to the free end of the sample, thus changing of sign and becoming a tensile pulse. Once the tensile pulse arrives on the notch, if the stress intensity resulting from the stress concentration at the notch tip is sufficient, a crack initates. The crack propagation process is filmed with an ultra-high-speed camera with 5 million frames per second (5 Mfps), that is 0.2 μs of exposure time. → This experimental technique, performed on a silicon carbide ceramic (Saint-Gobain's Forceram® SiC), can be used to characterise the dynamic crack velocity when coupled with Digital Image Correlation (DIC).