Analytical Characterisation in Mode I Fracture of Adhesively Bonded Double Cantilever Beam Mixed Glue Joints

This paper studies experimental and analytical investigations on mode I crack opening of GLT made by multi tropical species to assess the influence of strength of glue joints on such assemblies. Indeed, it should be noted, however, that for any glued composite element, the integrity and the strength of the glue joints are a basic prerequisite for the structure. Specimens are tested in Double Cantilever Bending (DCB), a crack is initiated on the glue joint to facilitate the delamination under a quasi-static loading. An analytical model is proposed for characterizing the fracture behaviour of an adhesively bonded double cantilever beam joint under Mode I loading. The full field measurement technique (grid method) was used to follow the crack propagation. A quantitative formulation for the energy release rate has been derived through the integration of beam theory and the compliance method. The analytical values of the energy release rate are compared with the experimental values obtained in a previous study. Results show that specimens composed of homogeneous glue joints and that cracking parameters are better when the initial crack is placed in the glue joint. The theorical values of homogeneous specimens are closets to experimental values in comparison with those of mixed specimens.