Analysis of the mechanical behaviour of composites and their bonded assemblies under out-of-plane loads using a modified Arcan apparatus
Résumé
Adhesively bonded assemblies, unlike riveted or bolted joints, do not require holes, which can lead to large stress concentrations in composites. For this reason adhesive bonding is attracting attention particularly when weight is critical. But failure in adhesively bonded assemblies involving composites is often associated with crack initiation in the adhesive or delamination of the composite plies close to the adhesive joint caused by interlaminar or through-thickness stresses. Such assemblies are often characterized by large stress concentrations, which make the analysis of their behaviour for industrial applications difficult. As the mechanical behaviour of adhesives and of composites are quite complex, a large database of experimental results under various loading conditions is necessary to develop accurate numerical models. Unfortunately, few experimental devices allow out-of-plane loading to be studied, except for specific loadings or by using thick composite specimens which are not always representative of industrial applications. This paper presents the possibilities of an experimental device, using a modified Arcan test, and optimized hybrid bonded assemblies, which limit the influence of edge effects. Some test results, showing the potential of the approach, are presented in the form of failure envelope curves for proportional monotonic out-of-plane loadings. Moreover, some aspects of the influence of low temperature on the mechanical behaviour of hybrid bonded assemblies with composites are analyzed.