Analytical Solutions for Singel-Lap Bonded Joints

The design of structural glued joints is a complex and open subject. There is currently no standard for the design of structural glued joints. A dimensioning approach is generally based on the comparison of a calculated criterion with a measured admissible criterion. Mechanical strength criteria can be defined theoretically and/or experimentally, and include safety factors derived from in-service experience. Their determination depends on the bonding system – defined by the combination of an adhesive, the prepared substrates and the manufacturing process –, the desired design strategy and requirements, and the properties of the adhesive used in the confined layer. The dimensioning approach therefore requires the definition of experimental characterization methodologies associated with calculation methodologies, dependent in particular on the modeling of characterized material behaviors.

This article deals with the adhesive bonding of two slender, flat structures, i.e. the bonded connection in simple shear, under quasi-static loading, possibly combined with uniform temperature variation. This type of structure can be found, for example, in the transportation (automotive, rail, naval, aerospace), energy or civil construction industries. Single-shear adhesive bonding is also widely used industrially to assess the mechanical performance of adhesive bonding. The aim here is to give the analytical solutions and associated hypotheses available in the literature, describing the stress distribution in the adhesive layer. Their limitations are also described and explained, while approaches based on semi-analytical resolution schemes are presented as alternative solutions. It is not the intention of this article to provide a design methodology for structural glued joints.