Experimental and numerical investigation of in-plane and out-of-plane impact behaviour of auxetic honeycomb boxes produced by material extrusion

Abstract

Auxetic structures, which have a negative Poisson's ratio, have good mechanical energy/impact absorption properties. These structures have found application in sandwich composites in the aerospace and defence industries, in the production of armour or protective sports equipment. In this study, the mechanical behaviour of the auxetic honeycomb structure in different directions (in-plane and out-of-plane) under impact loading was investigated. For the in-plane (x and y) and out-of-plane (z) directions, boxes with an auxetic honeycomb structure were produced by material extrusion method using Power ABS filament. In the experimental study, dynamic tests were carried out with a drop test machine. Besides, explicit analyses were performed by creating finite element models for these 3 directions. The experimental and numerical results have shown that the energy absorption property of auxetic honeycomb geometry is superior in the case of out-of-plane loading, in agreement with each other. In in-plane loadings, crush force efficiency (CFE) and crush forces were lower.