Enhancing the Out-of-Plane Compressive Performance of Lightweight Polymer Foam Core Sandwiches

Abstract

This study investigates the flatwise compressive performance of the developed sandwiches with core stitching modification. Polyvinyl chloride (PVC) foam cores with a density of 0.048 g/cm3 were stitched with 600-tex glass fiber yarns. Then the core materials were sandwiched with carbon/epoxy and glass/epoxy face sheets, respectively. The composite sandwich structures were produced by applying the vacuum bag method, and the composite layers were co-cured. The non-stitched foam core sandwiches were also manufactured as the benchmark. The developed sandwich panels were subjected to flatwise compression tests per the ASTM C365 Standard to obtain compressive properties. The mechanical testing showed that the stitched foam core sandwiches carried dramatically higher compressive loads and presented additional load peaks. The increments in the compressive strength of the developed sandwich panels were found above 80% without a significant weight penalty. Core stitching, providing the sandwich panels to have better out-of-plane strength, is a simple and less time-consuming through-thickness reinforcement process among the other core modification methods.

Keywords

• core stitching
• flatwise compression
• sandwich composite
• strength
• modulus

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