Abstract:

An enhanced structure with negative Poisson's ratio was proposed to improve the structural durability and achieve light-weighting of vehicles. The enhanced structural consisted of embedded tubes, which composed of thin-walled square tubes imbedded into double arrow lattice. The coupling effect between the negative Poisson's ratio structure and the embedded tubes was enhanced through the shrinking effect of negative Poisson's ratio. A finite element model of the enhanced structure was established with its accuracy being verified through compression tests. By using numerical methods, the durability performances of the double arrow lattice structure, the structure-filled tubes, and the enhanced structure with negative Poisson's ratio embedded tubes under axial loads were compared, and parameter analysis was conducted. The results show that the total absorbed energy of the enhanced structure is 1.12 MJ, an increase of about 40% compared to the double arrow lattice structure and filled tube structure; The specific energy absorption is 13.2 kJ, an increase of about 30%; The structure-filled tube structure with short beam angle of 70°, long beam angle of 40°, long beam thickness of 1.4~1.6 mm, and short beam thickness of 1.2 mm has greater specific energy absorption and smaller collision peak force; Increasing the thickness of embedded tubes significantly improves durability performance, but the structural mass increases sharply; The embedded tube thickness of around 1.2 mm meets the requirements of durability and light-weighting simultaneously.

Key words: passive safety of automobiles, vehicle light-weighting, structural crashworthiness, negative Poisson’s ratio, thin-walled tube