Screwed joint for aluminium extrusions: experimental and numerical investigation

The extrusion technology provides a variety of possibilities to join aluminium profiles. Special joint systems can be obtained by means of mechanical fasteners located in semi-hollow parts of specific aluminium extruded shapes. The great interest of the aluminium industry on these joints is due to many advantages: easiness, simplicity, rapid execution, optimization of parent material, treatments and machining reduction. A typical case of these special joints consists of a screw engaged in a open slot of an extruded profile. This system is usually named screw-groove joint and it is commonly used for joining aluminium profiles. Screw-groove joints are used in several structural and non applications under low and moderate loads such as façades, door and window frames. Nevertheless, no clear design rules are provided by the main codes for aluminium structures. For this reason an experimental campaign aimed at assessing the pull-out behaviour of screw-groove connections has been carried out at University ???Federico II??? of Naples. The influence of different parameters have been investigated such as the configuration of screw location, the type of aluminium alloy and the screw in terms of thread typology, diameter and embedment length. In addition, on the basis of experimental results, non-linear finite element models have been developed and calibrated.