Effect of Friction in Sliding Contact of a Sphere Over a Viscoelastic Half-Space

Imperfect elasticity of contacting solids results in hysteretic losses during the deformation. In rolling/sliding contact, the losses cause the resistant force, which is called the mechanical component of the friction force. Another cause of the friction is related to the energy losses in formation and breaking of the adhesive bridges between the contacting bodies (adhesive component of friction). In this study the combined effect of the adhesive and mechanical components of friction is analysed based on the consideration of the 3-D contact problem for the spherical indenter sliding with a constant velocity at the boundary of the viscoelastic half-space. The material properties are characterized by the linear viscoelastic solid with one relaxation time. The Coulomb-Amonton law of friction is used to describe the adhesive friction inside the contact region. A numerical-analytical method is developed to solve the contact problem and to find the contact stress distribution. The dependence of the mechanical component of friction force on the adhesive friction coefficient for various load-velocity conditions is studied.