Role of stress-state on mode-I fracture of adhesive bonded joints

In the fracture behavior of adhesive bonded joints, the adhesive layer thickness is known to play a significant role. Fracture data from mode-I testing of an aluminum alloy double cantilever beam bonded with an epoxy based structural adhesive is well simulated by plain strain simulations using a triaxiality dependent cohesive zone model (TCZM). As observed, the thinner adhesive layer develops higher constraint compared to relatively thicker adhesive layers and in order to capture these effects for different constraint conditions it is shown that, cohesive model that incorporates the stress-state effects in traction-separation law is better suited than a conventional fixed cohesive law.