关键词: 负泊松比, 蜂窝结构, 耐撞性, 复合材料梯度, 厚度交替梯度

Abstract: Based on the concept of gradient, two kinds of negative Poisson's ratio honeycomb structures with composite gradient and thickness gradient were proposed, and the effects of different gradient characteristics on their crashworthiness were studied. Compared with the traditional non-gradient honeycomb, the platform stress and energy absorption characteristics of the two kinds of gradient structures were studied, and the strengthening mechanism was revealed by analyzing the deformation mode of the honeycomb cell during the compression process and the negative Poisson's ratio effect. The results show that the predicted compression deformation is similar to the reference results. Compared to traditional honeycomb structure, a strain of 0.6 in honeycomb composite gradient increased platform stress by 27.6% and the energy absorption by 70.5%, thickness of honeycomb alternating gradient increased platform stress by 243% and the energy absorption by 166%, and the increase rate of the platform stress of the gradient honeycomb shows a gradual mode, and the compression deformation mode shows an alternating plastic deformation. Compared with the composite gradient honeycomb structure, the alternating thickness gradient honeycomb structure has higher platform stress and specific energy absorption during the compression process. When the normal strain is 0.6, the platform stress of the alternating thickness gradient honeycomb structure is 169% higher than that of the composite material gradient honeycomb structure, and the specific energy absorption of the thickness alternately gradient honeycomb structure is 55.7% higher than that of the composite material gradient honeycomb structure, which has stronger energy absorption ability. The gradient structure has obvious effect on the negative Poisson's ratio of each honeycomb layer.

Key words: negative Poisson's ratio, honeycomb structure, crashworthiness, composite material gradient, alternate thickness gradient