Determination of the interface properties in an elastic film/substrate system

Based on the assumption of constant-stress (Dugdale) interface bonding, a theoretical model is established in order to characterize the entire peeling response of an elastic film from a rigid substrate. The relationship between the peeling force and the peeling displacement and the relationship between the cohesive zone length and the peeling displacement at different peeling stages are analyzed. Closed-form solutions of the maximum peeling force and the maximum length of cohesive zone are further derived theoretically. It is found that both the maximum peeling force and the maximum length of cohesive zone depend on the interface strength, interface toughness and bending stiffness of the film. Combined with the classical Kendall's model, the cohesive zone length in the steady-state peeling stage is further given. A new method to simultaneously determine the interface strength and interface toughness is proposed, as long as the maximum peeling force, steady-state peeling force and film's bending stiffness are obtained from peeling tests. The results of this paper should be very helpful for interface performance prediction and interface design of film/substrate systems.