Compression behavior of the graded metallic auxetic reentrant honeycomb: Experiment and finite element analysis

In this paper, the quasi-static compression behavior of graded metallic auxetic reentrant honeycomb was firstly studied. Using the selective laser melting method, the unidirectionally-graded auxetic honeycomb (UGAH) and bidirectionally-graded auxetic honeycomb (BGAH) with the equal mass were fabricated to conduct the compression tests. The deformation mode, crushing stress and Poisson's ratio distribution of graded auxetic honeycombs were presented. Experiment results showed that the compression behavior of graded auxetic honeycomb was different from that of graded honeycomb with positive Poisson's ratio owing to the horizontal shrinkage deformation and the gradient distribution had effects on the crushing stress and Poisson's ratio. Then, a finite element (FE) model of the graded auxetic honeycomb was established and the calculation results were systematically compared with the experimental results. The effects of gradient distribution on the energy dissipation characteristics of the graded auxetic honeycomb were studied. The results showed that the energy dissipation of the UGAH was lower than that of the BGAH before the graded layer with the maximum cell-wall thickness was densified.