Experimental and numerical studies on the compressive mechanical properties of the metallic auxetic reentrant honeycomb

Highlights: • The experimental and numerical methods were used to accurately investigate the compressive behavior of the reentrant honeycomb. • The negative Poisson's ratio (NPR) effect on the crushing stress was clarified by the quasi-static compressive experiments. • Experiment results found that the NPR effect only had an amplified effect in the strain hardening stage. • In order to accurately investigate the compressive behavior of the reentrant honeycomb, the minimum cell's number should be greater than four. -- Abstract: In this paper, not only the effect of cell-wall thickness on the deformation mode of metallic auxetic reentrant honeycomb was firstly studied, but also the negative Poisson's ratio (NPR) effect on the crushing stress was also clarified by the quasi-static compressive experiments. Firstly, two types of typical reentrant hexagonal honeycombs with thin-walled and thick-walled cells were manufactured and compressive tests were carried out to characterize the deformation modes, negative Poisson's ratio distribution and crushing stress. Experiment results showed that the deformation mode of thin-walled honeycomb was quite different from that of thick-walled honeycomb, which has not been found in the existing reported papers. Secondly, a finite element (FE) model of the reentrant honeycomb was established and the FE results were systematically compared with the experimental results. The effects of honeycomb cell's number on the compressive deformation and the crushing stress of the honeycomb were studied. The results showed that once the honeycomb contained more than four cells in both transverse and horizontal directions, both the compressive deformation and the crushing stress were close to the experimental results. Finally, the energy absorption characteristics of reentrant honeycomb during compression were discussed.