A Study on 3D Printed CFRP-Metal Sandwich Structures for Hydrogen Transportation and Storage in Aerospace and Automotive Systems

This study investigates the mechanical performance of 3D-printed Carbon Fiber Reinforced Polymer (CFRP)-metal sandwich structures, focusing on infill pattern, infill ratio, and build orientation. The work primarily targets lightweight applications in hydrogen storage for aerospace and automotive sectors. Tensile and flexural tests were first conducted on non-sandwich specimens based on an earlier study [1], considering (i) infill patterns - Gyroid and Triangular and (ii) infill ratios - 30%, 40%, and 52%. In tensile tests, strength increased with infill ratio, with Triangular infill consistently outperforming Gyroid, peaking at 863 N (Triangular 52%) versus 777.5 N (Gyroid 52%). Lower displacement in Triangular indicated higher stiffness. Flexural tests on non-sandwich specimens showed Gyroid 40% achieving the highest load (644.85 N), while Triangular 52% exhibited steady strength gains with increasing density. Selected configurations were further tested in sandwich structures (CFRP-stainless steel with nickel coating), where Gyroid 40% demonstrated the highest load-bearing capacity (1008.55 N), followed by Triangular 52% (717.09 N). Notably, Gyroid 52% showed the greatest extension (14.38 mm) despite lower strength, indicating enhanced ductility. Overall, the results highlight a trade-off between stiffness and compliance, suggesting Triangular infill for high-strength, rigid components and Gyroid for balanced flexural performance. Overall, this work provides an impactful study on optimizing CFRP-metal hybrid designs for hydrogen storage systems.