Multi-objective optimization of a bi-material enhanced double-arrow honeycomb for improving load-bearing capacity and energy absorption

Abstract Multi-step deformable metamaterials usually exhibit a deficiency in auxetic behavior, which limits their potential for improving load-bearing capacity and energy absorption (EA). In this study, a bi-material enhanced double-arrow honeycomb (EDAH) is proposed by integrating a multi-step deformation mechanism with a double-arrow honeycomb design. Under in-plane compression, the structure exhibits dual stress plateaus and a stable transformation of the Poisson’s ratio. The first stress plateau corresponds to recoverable elastic deformation, whereas the second, approximately an order of magnitude higher, is dominated by plastic deformation and significantly enhances EA efficiency. The multi-level EA and auxetic behavior of EDAH under quasi-static compression are systematically investigated through experiments, theoretical modeling, and numerical simulations. Comparative analyses with traditional double-arrow structures reveal that the incorporation of bi-material composition and straight-rib elements in the EDAH design substantially enhances the second stress plateau and EA capacity without altering the auxetic effect. A comprehensive parametric study is conducted to propose an optimized design strategy for EDAH configurations. The optimization results demonstrate improvements in load-bearing performance, EA efficiency, and structural quality compared to the initial configuration. This study provides valuable insights for the development of multi-step metamaterials with superior energy absorption and load-bearing capabilities.