OS09W0440 The effect of shape memory alloy TiNi actuator on suppression of mode II delamination crack in CFRP laminates

This study proposes an intelligent composite material structure that suppresses Mode II delamination crack in CFRP laminates. Pre-strained shape memory alloy TiNi sheets were attached on the surface of CFRP specimens in order to investigate the effect of the recovery strain of the SMA actuators on the delamination crack propagation behavior under static loading. Mode II interlaminar fracture toughness tests were conducted on the two types of specimens: One is CFRP laminates with a compressively pre-strained SMA actuator on the compressive side of the specimen. The other has an additional SMA actuator with tensional pre-strain on the tensional side of the specimen. The results show that the fracture toughness increased due to the attachment of the SMA actuators even in the range away from the actuators for the both types of the specimens. In the specimen with the SMA actuator on one side, the fracture toughness increased further by the application of heat to the actuator. This is attributed to the effect of the recovery strain to suppress the mode II interlaminar crack. On the other hand, specimens with the SMA actuators on the both sides didn't exhibit much improvement in fracture toughness.