Design and quasi-static responses of a hierarchical negative Poisson's ratio structure with three plateau stages and three-step deformation

To solve the problems that the existing negative Poisson's ratio (NPR) structures only exhibit single plateau stage and irregular deformation modes, a novel hierarchical NPR structure called rotating star-circle structure (RSCS) was proposed. We respectively replaced the hinges and the rigid solid square in the classical rotational rigid square with the beam-like links and star-circle substructure. Through the quasi-static experiment, the FE modeling was validated. According to energy conservation, a theoretical model was established to predict the equivalent elastic modulus. The FE analysis was carried out to verify the theoretical model. The deformation modes and compression responses were studied by the FE method. It was found that there were three-step deformation and three plateau stages. Further, the deformation mechanisms were revealed based on the deformation modes and mechanical responses. Additionally, the parameters study showed that the geometric configuration significantly affected the deformation modes and mechanical responses. Compared with other auextic structures in the SEA, the RSCS exhibited better energy absorption. Lastly, we proposed a general design method based on the equal chord division to construct the multi-plateau structure. This research was a reference for the multi-functional application of the NPR structure and improving their energy absorption.