@article{ref1,
title="Crash Performance of Cellular Foams With Reduced Relative Density Part 2: Rib Deletion",
journal="International journal of crashworthiness",
year="2007",
author="Henderson, B. and Whitty, J. P. M. and Myler, P. and Chirwa, C.",
volume="12",
number="6",
pages="689-698",
abstract="The finite element method has been used to investigate the crashworthiness of regular conventional and re-entrant cellular foams in pristine and defect forms. Defects were introduced by randomly deleting vertical ribs (cell walls), diagonal ribs and vertical-plus-diagonal ribs from the honeycomb models, which with suitable boundary conditions approximated to three-dimensional foams. Generally, the calculations show that deleting ribs leads to a reduction in magnitude of the Young's moduli and Poisson's ratios, although there are some notable exceptions. In particular, the Young's modulus and Poisson's ratio along the x-axis (perpendicular to the vertical ribs) actually increase in magnitude slightly when vertical ribs are deleted. In the case of the re-entrant honeycomb, a transition from auxetic (negative Poisson's ratio) to non-auxetic (positive Poisson's ratio) behaviour occurs at a critical threshold for diagonal rib deletion. For the conventional honeycomb, the Poisson's ratio for loading in the y-direction remains approximately constant when diagonal ribs are deleted.<p />",
language="",
issn="1358-8265",
doi="10.1080/13588260701789425",
url="http://dx.doi.org/10.1080/13588260701789425"
}