Contact Region of a Hard Ball Rolling on a Viscoelastic Plate

Abstract

In the work presented, the contact region of a glass ball rolling without slip on a flat plate of viscoelastic material at various velocities was recorded. An interference microscope was used. Deformation of the base in the vicinity of the contact area was read from the interference picture obtained due to a narrow air gap between the ball and the base. The material of the base was characterized by creep and relaxation functions at constant temperature of (21 ± 0.5) deg C. The viscoelastic continuum of the base was replaced by the system of mutually independent vertical columns. By a subsequent twofold application of Boltzmann’s superposition principle, the diameter of the contact surface parallel to the velocity vector of the ball and depth of the concave track behind the ball were calculated. The results obtained were compared with observation data. Satisfactory agreement in cases where the shape of the contact area does not differ considerably from a circle (for small and great rolling velocities) was obtained.