Impact of the load level on the creep behaviour of adhesively bonded fastener in tension: experimental investigations, analytical and numerical modelling
Résumé
The use of structural adhesive bonding is increasing in structural assembly. It has indeed several advantages compared to other assembly techniques such as welding and riveting: uniform stress distribution, assembly of materials with different natures, no heat production. This last aspect is particularly interesting for the offshore activities. The firm Cold Pad has developed adhesively bonded fastener solutions, whose aim is to replace welding by structural bonding for the reinforcement of steel structures. Yet, some issues remain about the appraisal of the durability for such assembly and particularly creep. To address this issue, experimental creep investigations were carried out at real scale for one geometry of a fastener bonded with a methacrylate adhesive, and at different tension load levels. An inverse identification method has been developed in a previous study to identify the material creep properties from these investigations, independently of the fastener geometry. Considering the industrial applications of this fastener, the aim of this modelling approach is to describe correctly the primary and secondary creep stages. In this article, this identification method was applied to all the experimental results, using the Burger creep model. The dependency of the parameters with the load level is highlighted, which led to a nonlinear model. These results were then compared to finite element investigations to verify the consistency of the method and its ability to correctly identify the adhesive creep behaviour. This offers good perspectives in the transposition of the study to alternative fastener geometries using simple analytical design approaches.Highlights Bonded fastener’s creep behaviour experimentally investigated under different load levels. Creep modelling using a nonlinear and analytical approach with Burger model Identification of the material creep properties from experimental investigations at real scale on the bonded assembly. Numerical model developed to assess the consistency of the analytical approach.