Aluminum hexagonal honeycombs loaded in their tubular direction have extremely
good mechanical properties, including high stiffness to weight and energy absorption
capacities. The corresponding load-displacement curve exhibits a long plateau
accompanied by small fluctuations. These fluctuations are due to the propagation of a
folding front through the studied sample, which is due to the creation of folds. This
plateau load makes honeycombs the perfect candidates for use as energy-dissipative
devices such as bumpers. Previous studies have largely focused on the study of the
plateau load with less attention given to the length of the folds. However, it will be seen
that this parameter is crucial for both the complete understanding of the mechanics of the
folding and the derivation of the plateau load. We present first an introduction to the
thematic of honeycomb. Then, the first model focuses precisely on the fold length. Two
hypotheses are considered, a correlation between elastic buckling and folding first and a
local propagation of the existing fold secondly. The second hypothesis is found to be
correct, and the results are good for thin foils. For thick foils, a geometric limitation
occurs, which makes the results less precise. Then, we are able to use the previous
kinematics for the folding and derive a new set of formulas for the plateau load. The
results are compared with experimental results and past formulas, and are found to be
good, especially for thin foils, where our results for the fold length are more precise.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/22620 |
| Date | 02 April 2007 |
| Creators | Favre, Benoit |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Detected Language | English |
| Type | Thesis |
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