Rate-dependent peeling behavior of the viscoelastic film-substrate system

In contrast to the well-understood peeling behavior of an elastic film-substrate system, the peeling behavior of a viscoelastic film bonded to a rigid substrate remains unclear. This paper established a theoretical peeling model, assuming a uniformly distributed cohesive interfacial interaction, to study the steady-state peeling behavior of a viscoelastic film. The rate-dependent behaviors of the steady-state peeling force and the cohesive zone length are mainly analyzed in the present paper. It reveals that there exist 3 typical peeling force-peeling velocity relations relying on the viscous dissipation within the film and the rate-dependent extent of the interfacial adhesion. In addition to the film's viscoelasticity and the peeling velocity, the film thickness, interfacial toughness, and interfacial strength are also identified as factors that influence the steady-state peeling force. For the cohesive zone length of peeling a viscoelastic film, the analytical expression is obtained which demonstrates a dependence on peeling velocity, film viscoelasticity, film thickness, interfacial toughness, and interfacial strength. The present theoretical findings are validated by the finite element simulation and are believed to facilitate the fundamental understandings and practical applications for viscoelastic film-substrate systems.