Frictional torque and compliance in collinear elastic collisions

Abstract Principles of dynamics together with a statical theory for deformation in the contact region are used to analyse changes in frictional torque and spin during collinear impact between rough elastic spheres. Spin is the normal component of relative angular velocity between two colliding bodies. Changes in spin are due to frictional torque of shear tractions acting on the contact patch during collision; the Hertz theory of local elastic deformation is used to calculate the finite radius of contact that generates torque. In the contact patch, the distribution of shear traction depends on tangential compliance and relative rotation.