Flexural response of sandwich composites integrated with 3D multi-layer stitched core

Abstract

This experimental study investigates the flexural response of sandwich composites integrated with 3D multi-layer stitched core. Polypropylene 3D multi-layer woven fabric impregnated with an epoxy resin was selected as the core, while E-glass fiber reinforced epoxy was used for the sandwich composite face sheets. The sandwich composite exhibited a ductile behavior when loaded in three-point bending as the core layers increased. This is due to the drop in core shear strength with the increased number of core layers. The core layers that were not directly connected with the face sheets deformed most under shear, resulting in a more flexible plate behavior. The number of core layers, size of core unit-cell and stitching density were the critical design parameters determining the flexural strength and stiffness of the sandwich panel. The flexural modulus of sandwich composites with higher stitching density core stiffer than those of lower stitching density.