Abstract：As a typical mechanical metamaterial, the material with negative Poisson's ratio will have the phenomenon of indentation resistance when impacted, which makes the impact resistance of the material significantly improved, and it has the characteristics of light weight and high energy absorption. Most of the previous studies focused on the mechanical properties of honeycomb structures under forward impact, but the study on the dynamic response of multi-cell structures with negative Poisson's ratio, especially those made of double material cells, under inclined load is very limited. However, the structural failure caused by inclined load impact cannot be avoided in engineering practice. In this work, the gradient design of multicellular structures is combined with the inclined load impact to study the energy absorption and crushing deformation modes of the structures. A gradient bimaterial negative Poisson's ratio honeycomb structure based on curved edge concave bimaterial cell is proposed in this paper. By changing the transverse and longitudinal curved bar materials, four kinds of material graded gradient honeycomb structures with positive gradient, negative gradient, symmetrical positive gradient and symmetrical negative gradient honeycomb structures are designed. The dynamic behavior of each gradient structure under in-plane oblique impact loading is studied by numerical method. It is found that the honeycomb structure with negative gradient bimaterial arrangement under oblique collision has the best energy absorption effect. For the bimaterial honeycomb structure with negative gradient, the deformation mode, nominal stress-strain curve and energy absorption effect are discussed in detail at different impact velocities and impact oblique angle. The results show that the impact velocity and impact oblique angle have great influence on the energy absorption effect of the model. No matter at what speed, the smaller the impact oblique angle, the better the energy absorption effect of the honeycomb structure, that is, the crashworthiness of the honeycomb structure decreases with the increase of the impact oblique angle.
2025, Vol. 46 
