A Many-Body Disk Model of Slip Phenomena and Disk Contact Networks—A Spin System with Frustration on Irregular Lattices

Takayuki Hirata¹, Hideki Goto, Tatsuaki Yoshimura, Atsushi Ogawa and Yoshifumi Harada

Department of Human and Artificial Intelligent Systems, Faculty of Engineering, Fukui University, 3-9-1 Bunkyo, Fukui 910-8507, Japan
¹E-mail: d970062@icpc00.icpc.fukui-u.ac.jp

(Received November 19, 1999; Accepted February 23, 2000)

Keywords: A Many-Body Disk Model, Frustration, Disk Contact Network, Slip Phenomena, Ising Spin, Irregular Lattice

Abstract. A many-body disk model of slip phenomena that was one of the system having frustrated states was investigated from the viewpoint of disk contact networks. Experiments were carried out by using acrylic resin disks packed into an annular cell that consisted of an outer rotating cylinder and an inner fixed cylinder. The time series of torque at the inner cylinder was measured as a macroscopic behavior of the system, and the motion of individual disks was monitored by a CCD video camera recorder as a microscopic elementary process. Distributions of n-path polygon loops in the disk contact networks and the coordination number of the disks were obtained.