In-plane dynamic crushing of re-entrant auxetic cellular structure

The impact response of the re-entrant auxetic honeycomb is studied by simulating its in-plane dynamic crushing with FE methods. The characteristics of the peculiar crushing patterns and modes in the re-entrant honeycomb are described. The energy absorption performances of the re-entrant auxetic honeycomb and the hexagonal honeycomb are compared. When subjected to the same magnitude of crushing strain, the re-entrant honeycomb can dissipate more energy through plastic deformation. But if the peak stress is the primary concern for the packaging material, the re-entrant structure tends to generate higher stress in order to dissipate the same amount of impact energy. Moreover, the structural irregularity of the re-entrant auxetic honeycomb is defined and its influence on the dynamic crushing is studied. Unlike the hexagonal honeycomb, the irregular re-entrant auxetic honeycomb can absorb more energy than the regular one in the quasi-static regime. This situation reverses under high speed impact. This study will help to understand the dynamic behavior of the re-entrant foam and provide references for its application. (C) 2016 Elsevier Ltd. All rights reserved.