Crack propagation in rubber-like materials

Crack propagation in rubber-like materials is of great practical importance but still not well understood. We study the contribution to the crack propagation energy (per unit area) G from the viscoelastic deformations of the rubber in front of the propagating crack tip. We show that G takes the standard form G(v, T) = G(0)[1 + f (v, T)] where G(0) is associated with the (complex) bond-breaking processes at the crack tip while f (v, T) is determined by the viscoelastic energy dissipation in front of the crack tip. As applications, we discuss the role of crack propagation for adhesion, rolling resistance and sliding friction for smooth surfaces, and for rubber wear.