1 Composites and Materials Mechanics, Materials Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark2 Materials Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark3 Risø National Laboratory for Sustainable Energy, Technical University of Denmark4 University of Skövde5 Department of Wind Energy, Technical University of Denmark
Mixed mode testing of adhesive layer is performed with the Mixed mode double Cantilever Bean? specimen. During the experiments, the specimens are loaded by transversal and/or shear forces; seven different mode mixities are tested. The J-integral is used to evaluate the energy dissipation in the failure process zone. The constitutive behaviour of the adhesive layer is obtained by a so called inverse method and fitting an existing mixed mode cohesive model, which uses a coupled formulation to describe a mode dependent constitutive behaviour. The cohesive parameters are determined by optimizing the parameters of the cohesive model to the experimental data. A comparison is made with the results of two fitting procedures. It is concluded that the constitutive properties are coupled, i.e. the peel and shear stress depend on both the peel and shear deformations. Moreover, the experiments show that the critical deformation in the peel direction is virtually independent of the mode mixity. (c) 2007 Elsevier Ltd. All rights reserved.
International Journal of Solids and Structures, 2007, Vol 44, Issue 25-26, p. 8335-8354