Energy Absorption Enhancement by Unit Cell Angle Grading or Sandwich Panels with Auxetic Core

Abstract

Architectured structures, particularly auxetic materials, have demonstrated encouraging applications in energy absorption as they facilitate the customization of their structural response. Specific geometries of unit cells can thus be tailored for particular needs due to recent progress in additive manufacturing techniques. This paper experimentally studies how the grading of the cell unit angle of an auxetic core in a sandwich panel affects its energy absorbing capability and structural response. 3D printed sandwich panels with uniform and graded auxetic cellular core were tested under quasistatic compression. The results show that sandwich panels with graded core exhibit much better energy absorption capabilities with higher plateau stress and densification strain. This indicates that, by appropriately controlling its geometry, auxetic structures can show further potential as core in sandwich panels for energy absorption applications.

Determination of Stress Concentration Effects Using Micro-Digital Image Correlation Techniques in PMMA Specimens

“…For parts of small dimensions or with complex geometries, it is often necessary to perform an analysis under a microscope. In the latter case, the complex geometry generates local effects when under load, such as buckling [8,9] and risk of affecting the entire structure. In case of mechanical testing, this requires both loading and strain response of recording equipments to be adapted for such a scale.…”