Abstract: The connection between metal and polymer is crucial for lightweight manufacturing in the electronics, automotive, aerospace industries and so on. Inspired by biological curves, this study proposes a novel biomimetic interlocking structure, designed specifically to enhance the metal-polymer joint strength. Through this approach, superior connection strength is achieved compared to conventional structures. Three different interlocking structures—Dragonfly Head-Neck interlocking structure, Kelvin interlocking structure, and the propopsed Curved Body-Centered Cubic Lattice interlocking structure— were additively manufactured with stainless steel, followed by injection molding to form the metal-polymer connection structures. The bonding performance of these structures was evaluated through finite element analysis and experiment. The results indicate that the Curved Body-Centered Cubic lattice interlocking structure with a 10% fill rate exhibited the highest bonding strength, outperforming both the Kelvin interlocking structure and the Dragonfly Head-Neck interlocking structure. Reducing the stiffness of the metal subatrate near the metal-polymer connection rigon can establish efficient load transfer path, which leads to a uniform stress distribution within the polymer, and allows the polymer to better withstand tensile forces during loading, finally achieve the goal of enhance the bonding strength of of the metal-polymer jointing. This research offers an innovative approach to enhancing mechanical connection interface strength, with significant implications for improving the durability and performance of metal-polymer composites.

Key words: Additive manufacturing')">Additive manufacturing, Biomimetic interlocking structure, Metal-polymer jointing, Injection molding, Connection strength