Numerical Modelling of Non-Linear Behaviour in Adhesively-Bonded Assemblies

摘要

The objective of this study is to define a reliable tool for the dimensioning of adhesively-bonded assemblies, particularly in marine and underwater applications, for which a lack of confidence currently limits the use of this technology. The first objective was to define an experimental methodology enabling the adhesives of interest to be characterised up to failure. A modified Arcan fixture, which allows compression or tension to be combined with shear loads, has been designed. It has been numerically shown, on one hand, that the use of a beak close to the adhesive joint makes it possible to strongly limit the contribution of the singularities due to edge effects. On the other hand, the geometry of the joint near to the edge is another important parameter. This experimental fixture associated with non-contact extensometry and optimisation techniques allows us to analyse, for radial loadings, the non-linear behaviour of an adhesive joint (results are presented for epoxy resin Vantico Redux 420). The second aim of this work was to develop a model in order to represent the evolution of the relative displacement of both extremities of the adhesive joint with respect to the stress state. This type of model can be justified by the thickness of the joint (0.5 mm or more for marine applications) and by the observation of a homogeneous deformation in the thickness of the adhesive joint. Moreover, this model allows us to use joint-type elements which strongly reduce the numerical cost with respect to classical elements. As the numerical simulations performed for linear behaviour of constituents have shown a non-uniform evolution of the state of stress in the adhesive joint, inverse techniques are used to identify the parameters of the model. Numerical applications, for radial monotonic loadings, show the possibilities of the proposed approach. Numerical studies of marine applications are underway in order to apply the analyses of the proposed modelling strategy to adhesively-bonded composite and metal/composite joints.