Failure study of gradient bimaterial negative Poisson's ratio honeycomb sandwich panels subjected to local impact

The sandwich panel structure, known for its lightweight nature, high bending stiffness, and exceptional impact resistance, can be tailored with a core layer of negative Poisson's ratio materials. This design approach yields protective structures with outstanding dynamic characteristics. In this paper, a negative Poisson's ratio biomaterial cellular sandwich plate with positive gradient, negative gradient, symmetric positive gradient and symmetric negative gradient was constructed by changing the vertical and horizontal materials in the cell based on the proposed curved edge concave negative Poisson's ratio biomaterial cell. The comparison between experimental results and simulation results demonstrates the feasibility of the numerical method proposed in this paper. The effects of punch impact velocity and gradient arrangement on the failure mode of sandwich plate, punch contact force and energy absorption were investigated. The results show that the impact failure mode and impact dynamic performance of the sandwich panels are significantly affected by the arrangement mode of core layers. This design can significantly enhance the energy absorption effect of sandwich panels.