MECHANICAL PROPERTIES OF ARC CONCAVE MULTICELL STRUCTURES OF BIMATERIALS WITH NEGATIVE POISSON'S RATIO

A bimaterial arc concave negative Poisson's ratio cell is proposed. The expressions for the equivalent Poisson's ratio and the equivalent elastic modulus are obtained by using the energy method. The present solution is in a good agreement with the finite element results. Using the obtained theoretical solution, discussed were the effects of arc angle, material matching and aspect ratio on the equivalent Poisson's ratio of the multicellular structure. Based on the proposed bimaterial arc concave cell, constructed was a bimaterial multicellular honeycomb structure. Using numerical methods, discussed were the deformation failure mode, dynamic response curve, energy absorption value per unit volume and energy absorption value per unit mass of the multicellular honeycomb structure under impact load. The results show that the higher the ratio of longitudinal/transverse modulus, the more obvious the negative Poisson's ratio effect is. Compared with the single-material multicellular structures, the bimaterial concave multicellular structures have different deformation failure mode during collapse. Compared with the single material structure, the bimaterial structures show excellent energy absorption characteristics.