Adhesive can be modeled with interface elements (element types 186 to 193) and cohesive materials. There are four standard cohesive material models available. The models have the following characteristics:
Exponential: entirely defined by an exponential function; the necessary material properties are the Cohesive Energy (Gc) and the Critical Opening Displacement (vc).
Linear: both the reversible and the irreversible part of the traction-displacement curve are linear; the necessary material properties are the Cohesive Energy (Gc), the Critical Opening Displacement (vc) and the Maximum Opening Displacement (vm), beyond which the traction is reduced to zero.
Linear-Exponential: the reversible part of the traction-displacement curve is linear, where the irreversible part is described by an exponential function; the necessary material properties are the Cohesive Energy (Gc), the Critical Opening Displacement (vc) and the Exponential Decay Factor (q).
Turon: Another formulation that uses thermodynamically consistent equations for the evolution of damage and traction is provided by the Turon model. This model is very similar to the Linear model, but it requires an extra parameter Eta (used in the B-K criterion), which can be used to accurately model mixed-mode delamination.
