Europhys. Lett., 63 (1) , pp. 146-152 (2003)
Bouncing gel balls: Impact of soft gels onto rigid surfaceY. Tanaka1, Y. Yamazaki2 and K. Okumura3, 4
1 Department of Mechanical Systems Engineering, Toyama Prefectural University Kosugi-machi, Toyama 939-0398, Japan
2 Department of Physics, Chuo University - Bunkyo-ku, Tokyo 112-8521, Japan
3 Department of Physics, Graduate School of Humanities and Science Ochanomizu University - 2-1-1, Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
4 Laboratoire de Physique de la Matière Condensée, Collège de France 75231 Paris Cedex 05, France
(Received 4 February 2003; accepted in final form 2 May 2003)
After being thrown onto a solid substrate, very soft spherical gels bounce repeatedly. Separate rheological measurements suggest that these balls can be treated as nearly elastic. The Hertz contact deformation expected in the static (elastic) limit was observed only at very small impact velocities. For larger velocities, the gel ball deformed into flattened forms like a pancake. We measured the size of the gel balls at the maximal deformation and the contact time as a function of velocities for samples different in the original spherical radius and the Young modulus. The experimental results revealed a number of scaling relations. To interpret these relations, we developed scaling arguments to propose a physical picture.
83.80.Va - Rheology: Elastomeric polymers.
46.70.Lk - Continuum mechanics of solids: Other structures.
81.05.Lg - Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials.
© EDP Sciences 2003