The Pseudo-Rigid Rolling Coin

Abstract

A pseudo-rigid coin is a thin disk that can deform only to the extent of undergoing an arbitrary affine deformation in its own plane. The coupling of the classical rolling problem with this deformability, albeit limited, may shed light on such phenomena as the production of noise by a twirling dish. From the point of view of analytical dynamics, one of the interesting features of this problem is that the rolling constraint turns out to be nonholonomic even in the case of motion on a straight line in a vertical plane. After the analytical formulation of the general problem, explicit solutions are obtained for special shape-preserving motions. For more general motions, numerical studies are carried out for various initial conditions.