Composite sandwich structures with rapid prototyped cores

Purpose - The purpose of this paper is to investigate the feasibility of using rapid prototyping (RP) technologies (stereolithography (SLA), fused deposition modeling (FDM), and three-dimensional printing (3DP)) for fabrication of the core of a composite sandwich structure. Design/methodology/approach - Control cores of a flat geometry were fabricated from epoxy using SLA and from acrylonitrile butadiene styrene (ABS) plastic using FDM. Corrugated geometry cores were fabricated using SLA, FDM, and 3DP. Carbon-epoxy composite sandwich structures were fabricated from all cores using a wet-hand layup process with vacuum cure. The performance of each core was measured using a bend test to determine bending stiffness and failure load. Findings - Based upon bending stiffness and failure load, composite sandwich structures utilizing epoxy cores fabricated via SLA outperformed composite sandwich structures utilizing plaster powder and ABS plastic cores. Composite sandwich structures with corrugated ABS plastic cores outperformed those with flat ABS plastic cores by a margin well beyond that predicted by theory in both bending stiffness and failure load. Research limitations/implications - The marked improvement in stiffness and failure load of the composite sandwich structures with corrugated ABS plastic cores over those with flat ABS cores is not explained by the theoretical improvement due to an increased area moment of inertia and increased surface area. Additional research in the failure mechanism is warranted. Practical implications The ability to easily create complex core geometries will allow for the ability to place enhanced structural features in the regions of high stress. Originality/value - This paper demonstrates that cores fabricated via RP technology and containing enhanced structural features are suitable for carbon-epoxy composite sandwich structures.