Development of new sandwich panels fabricated with Vinylester (PVC)/ glass surface and PVC core for automobile applications

A vacuum-injection-based fabrication method is proposed for producing lightweight sandwich panels for automotive applications. Unlike conventional adhesive bonding, this process forms the face sheets and their connection to the grooved PVC foam core in a single step, reducing manufacturing cost, increasing production speed, and improving interface quality. The sandwich structure consists of a grooved polyvinyl-chloride core and fiberglass/vinyl-ester face sheets, materials commonly used in the automotive industry. Mechanical performance was evaluated under bending and compression loading. The results show that panels fabricated using the proposed method exhibit significantly higher strength than those produced by adhesive bonding. Specifically, bending strength increased by 78% and compressive strength by approximately 40%. This improvement is attributed to the formation of a resin network within the grooves of the PVC core, which enhances core stiffness and strengthens the surface-to-core bond. The novelty of this study lies in introducing a simple reinforcement strategy that substantially improves bending and compressive performance while maintaining low density, offering a lightweight alternative to conventional composite configurations. The resin network created within the grooved core forms a structure analogous to a foam-filled honeycomb, contributing to the enhanced through-thickness mechanical response.