Experimental and numerical analysis of a novel 3D re-entrant auxetic structure

The energy absorption performance during collisions and crushing is one of the critical parameters in the design of vehicle structures. Therefore, researchers are continually trying to improve the energy-absorbing properties of the crash box to reduce the force transmitted to the occupant during an accident. In this research, a novel three-dimensional re-entrant auxetic structure has been proposed to improve energy-absorbing performances. Criteria for evaluating energy absorption including the initial peak crushing force, energy absorption, mean crushing force, crushing force efficiency, and specific energy absorption, were obtained through numerical and experimental methods. The structure showed auxetic behavior in two transverse directions during compressive loading and absorbed more energy. The force-displacement curve showed low initial peak crushing force, and the structure collapsed uniformly during compressive loading. The effects of the angle of the diagonal strut with the vertical axis, the thickness of the struts, and the ratio of horizontal strut length to diagonal strut length on the energy absorption properties of the structure were studied, too.