Analysis of Sandwich Composite Manufacture with Triaxial-Processed Foam Core by Vacuum-Assisted Resin Infusion Moulding and Resin Reinforcement

This study aims to improve the penetration of fluid resin from top to bottom of a sandwich composite with common single double-sided square deep-groove foam core and multi-axial fibre-stitched fabric-skin layer in vacuum-assisted resin infusion moulding (VARIM). Through common cutting and drilling, six kinds of composite slot hole structures were designed based on their vertical and horizontal deep grooves, surface grid shallow grooves, and vertical cylindrical deep holes as unit structures. Optimisation and comparative analysis of the composite slot structures were then conducted based on the amount of fluid resin that penetrated the slot structure, total area of the seepage hole section, and time required for the fluid resin pass through the orifice, among others. The composite slot hole structure (No. III) was determined as the optimised slotted hole structure based on the comparative analysis of the penetration of fluid resin from top to bottom in the VARIM manufacture process and reinforcement effect of the resin structure on the sandwich composites, where the points for comparison were the optimised design composite slot hole (No. III) and common single double-sided square deep-slot (No. i) resin/foam cores. For the sandwich composite with the composite slot (No. III), the total area of the seepage hole section from top to bottom of the composite was larger by approximately 10 dm2, the flow velocity of fluid resin in the pore quadrupled, the time for the fluid resin to pass through the orifice was significantly shorter, and the flat compression and shear strength of the composite improved by 47% and 85%, respectively.