Design of Experiment for Mechanical Joints Inspired by Diabolical Ironclad Beetles and Japanese Wood-Working Joint

Abstract In this study, a design of experiment (DOE) is conducted to understand the performance of 3D printed mechanical joints, which are inspired by the diabolical ironclad beetle (DIB) and designed based on a Japanese wood-working joint. The elytra of the DIB exhibit extraordinary damage-tolerance due to the unique micro-scale interfacial joining features at its medial suture. Their suture not only improves toughness by creating a flexible joint that can dissipate energy but also limits the total deformation of the junction due to the interlocking mechanism. This work also draws inspiration and further explores different configurations of a traditional wood-working joint from Japanese carpentry, known as the “four-way goose-neck joint” or shihou-kama-tsugi . This unique joint geometry is designed, 3D-printed for testing, and analyzed for its tensile joint strength characteristics. Results show that interlocking configurations with the highest interaction between baseline and midpoint dimensions provide the greatest joint strength. This study reveals how geometrical parameters of joint design affect the joint strength, failure modes of the joints, and the damage mechanisms involved.