Adjustable mechanism of a novel bimaterial shuriken-shaped auxetic structure with stiffness enhancement

Owing to their unique performance advantages, auxetic materials hold broad and promising application prospects. Such materials often suffer from insufficient stiffness, a challenge that requires urgent resolution. Therefore, this paper proposes a novel bimaterial shuriken-shaped auxetic structure (BSAS) with enhanced stiffness behavior. For the BSAS, an effective and accurate mechanical property assessment model is established using the direct stiffness method, with its validity verified through finite element analysis. The influence of geometric parameters on the elastic constants and Poisson's ratio of the BSAS is investigated, and the interaction mechanisms between parameters are analysed. Concurrently, mechanical property comparisons are also made with the stiffness enhancement auxetic structures. The results indicate that the relative elastic modulus of BSAS can be 10 times that of windmill-shaped structure. Compared to the windmill-shaped structure, the BSAS sacrifices 38% of its auxetic performance in exchange for a 1006% increase in stiffness. This research provides a theoretical foundation and design insights for stiffness enhancement strategies in novel auxetic materials.