Adhesive-joint geometrical configuration

Closed form solutions. Structural adhesive joints are generally designed to be loaded in shear so that treatments of joint analyses are confined essentially to the transfer of load by shear, with some consideration of the transverse normal stresses induced by eccentricities in the load path. In the simplest case the adhesive and the adherends are assumed to behave elastically. The most refined analyses attempt to model the situation when the adhesive yields so that the adhesive and, eventually, the adherends behave plastically as the imposed load is raised. Closed-form analyses are difficult to apply to other than simple geometrical configurations, while a major difficulty with the elasto-plastic model is how to characterise the adhesive. 

The most common adhesive bond is the overlap or lap type. There are many variations of the overlap joint but the simplest type is the single-lap joint. This configuration has been the subject of much work (see Section III) so the geometric factors which effect joint design, such as bond area or overlap length and adherend thickness are well known. 

The simplest geometric configuration of adhesively bonded structures is probably the single lap joint (SLJ), which has been widely used as a standard test specimen to calibrate adhesive properties and has been shown to be representative and challenging in identifying fundamental characteristics and key parameters in bonded lap joints. 

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