Peel-Strength and Energy Dissipation

The effect of energy dissipation on peel-strength is discussed on the basis of mechanics. In the case of T-peeling of specimens consisting of two flexible tapes bonded by elastic adhesive, steady peel-strength is simply given as 2f = Γ, where f is the peeling force per unit width of the tape and Γ is twice the surface energy of the fracture surface. However, in the cases where the energy is dissipated in the adhesive layer or in the adherends, another term w’ representing the energy dissipation is to be added to the peeling force, i.e. 2f = Γ + 2w’. The energy w’ associated with the deformation of the adhesive layer is given by the work done at the tip of the crack per unit length of the adherend during a cycle of the elongation to fracture and subsequent recovery of the adhesive. This energy w’ can be estimated from an area u’ enclosed by the stress-strain hysteresis curve obtained from extention test of the adhesive and the thickness h of the adhesive layer, as 2w’ = hu’.