Mechanical characteristics of 3D‐printed honeycomb sandwich structures: Effect of skin material and core orientation

Abstract Sandwich structures are crucial in automotive, and construction industries due to their lightweight, high‐strength properties, insulation, and energy absorption capabilities. In addition, 3D‐printed sandwich structures are important due to their customizable geometry and controlled material distribution, which enhance strength and stiffness. This study examines the mechanical properties of composite sandwich structures with a 3D‐printed honeycomb core. The composite skin, fabricated using the wet hand lay‐up method, consists of glass, carbon, and epoxy resin, while a fused deposition modeling machine produces the polylactic acid (PLA+) honeycomb core. A full factorial design and analysis of variance were employed to evaluate the effects of skin material and core orientation on mechanical properties through compression and three‐point bending tests. The mechanical performance of sandwich structures improved through core‐skin synergy, enhancing load distribution and resistance. Carbon/epoxy skins offered stiffness and strength, delaying failure modes, while glass/epoxy provides flexibility and cost‐efficiency. Hybrid skins combined these benefits, enhancing stability. In addition, vertical core orientation further maximized load capacity and minimized buckling compared to horizontal alignment. Optical analysis revealed buckling and crack propagation as primary failure mechanisms. Last but not least, finite element analysis using ABAQUS confirmed qualitative similarity in load–displacement curves and deformation behavior with experimental results. Highlights Mechanical properties of 3D‐printed sandwich structures were analyzed via the design of experiment. Vertical core orientation improves compressive and flexural properties over horizontal cores. Carbon/epoxy skins deliver superior flexural and compressive strength in sandwich panels. Failure mechanisms include core buckling, cell wall debonding, and skin wrinkling/cracking. Finite element analysis results closely aligned with experimental tests, validating structural behavior predictions.