Compression after impact performance of carbon-fiber foam-core sandwich composites in low temperature arctic conditions

Abstract

This study investigates the compression after impact (CAI) behavior of carbon-fiber foam-core sandwich composites in low temperature arctic conditions. Low-velocity impact and CAI tests are experimentally conducted across temperature from −70 °C to 23 °C. Results show higher compressive strength for non-impacted specimens at low temperature. However, upon impact, severe damage and complex failure modes at low temperature lead to significant reduction in CAI strength by 60%. X-ray micro-computed tomography reveal additional CAI damage mechanisms, such as auxiliary facesheet matrix cracking, localized back facesheet delamination-induced buckling, and front facesheet debonding. The types of CAI damage modes and failure locations are apparently different for room and low temperature conditions. The findings of this study are supported by a newly proposed analytical model that predicts CAI performance using fracture mechanics based concepts. This work evidently demonstrates that the damage tolerance of sandwich composites is severely reduced at low temperature conditions.