Effects of Material Combinations and Curvature on the Failure of Sandwich Structures

Abstract

In this study, influence of material combinations and curvature on failure of a curved composite sandwich structure has been investigated numerically and both factors were found to be influential. Tsai-Wu and Puck criteria were adopted to evaluate the core and facesheet laminate failure, respectively. For constant curvature, core failure was found to be the first failure event for sandwich structures designed with PVC core while the initial failure mode switched to inter-fiber failure (IFF) in facesheet when the core material was replaced with Balsa. Curvature was also found to be impactful by contributing to high through-thickness normal stresses in the curved region of sandwich structures. A decrease in curvature would lead to the reduction of magnitude in through-thickness stresses, which could eventually result in the switch of failure mode from core failure to IFF for sandwich structures designed with PVC core. Finally, it was found that sandwich structures with more unidirectional fabric content in facesheet are more prone to the initiation of IFF.