Energy absorption in a bamboo foamA. Le Goff1, L. Courbin2, H. A. Stone2 and D. Quéré1
1 Physique et Mécanique des Milieux Hétérogènes, UMR 7636 du CNRS, ESPCI - 75005 Paris, France, EU
2 School of Engineering and Applied Sciences, Harvard University - Cambridge, MA 02138, USA
received 31 July 2008; accepted in final form 16 September 2008; published November 2008
published online 15 October 2008
We discuss the ability of soap films to absorb the energy of an impacting projectile. If the impact velocity is large enough, solid objects or water drops pass through the films without breaking them. However, during each impact a small part of the original kinetic energy is extracted, which is revealed by considering collections of parallel films (so-called bamboo foams). Then, the impacting object is observed to stop after crossing numerous films. The total energy absorbed by the foam is found to be the total energy of distortion of the films, integrated over the multiple crossings. The case of inclined films is also considered, and found to affect the trajectory of the projectile.
68.03.-g - Gas-liquid and vacuum-liquid interfaces.
47.55.D- - Drops and bubbles.
47.57.Bc - Foams and emulsions.
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