A MODEL OF DAMAGED ADHESIVES

The behaviour of adhesively bonded joints undergoing interfacial failu re is investigated, using a continuum damage mechanical description fo r the adhesive. From a thermodynamical framework, three-dimensional co upled elastic-damage evolution equations are derived. The gradient of the damage variable is introduced in the free energy, so that the mode l accounts for the intrinsic cohesion of the adhesive. The subdifferen tial of the damage potential function is determined in a rigorous way, from which the evolution laws for the internal variables associated w ith the damage are deduced. A generalisation to the coupling of damage with elastoplasticity is given. A two-dimensional model of a thin ela stoplastic damaged adhesive is then derived, using a perturbation meth od. Finally, a finite element simulation is implemented, which predict s in a satisfactory way the experimental rupture forces for a simple t est.