Exploring mechanical performance and innovative core design in 3D-printed PLA sandwich panels: a lightweight and modular approach with arch-corrugated cores

Modular structures are essential for enhancing construction efficiency, reducing costs, and providing flexibility in design across various industries. Sandwich panels, composed of stiff outer skins and lightweight cores, are widely recognized for their high strength-to-weight ratios, durability, and adaptability. Among core designs, arched corrugated cores stand out for their ability to enhance structural performance while allowing easy integration of utilities and improving insulation properties. Despite their potential, modular sandwich panels with advanced core configurations have not been extensively explored. This study introduces an innovative modular sandwich panel design that is both assembleable and disassembleable, utilising 3D-printed arched corrugated cores made from polylactic acid (PLA). Six core configurations (P1–P6) are tested, varying in arch orientation (downward or upward), arrangement (alternated or aligned), and inclusion of semi-arches. The panels undergo three-point bending tests to evaluate their mechanical performance. Quantitative results demonstrate the superiority of the P6 configuration, which achieves the highest performance across all metrics. Compared to the second-best-performing configuration, P2, P6 exhibits a 29% higher maximum load capacity and a 23% greater flexural modulus. Yield mean stress for P6 surpassed P2 by 24%, and ultimate mean stress improved by 28%. Additionally, P6 demonstrated a 26% higher modulus of resilience and a 16% increase in toughness. These findings highlight the potential of modular, 3D-printed sandwich panels with optimised arched core designs for applications in construction, transportation, and energy absorption. The ability to assemble and disassemble these panels offers additional versatility for reuse and customisation across diverse applications.