Macroscopic strength and failure properties of flow-drill screw connections

Abstract

Force-displacement responses and failure behaviour of connections using flow-drill screws to join aluminium sheets were investigated under various quasi-static loading conditions. This included single connector tests under tensile, shear and combined tensile and shear loadings, using cross test coupons in a new test set-up, and peeling and single lap-joint tests. The strength of the connection increased with the amount of shear loading, while the ductility decreased. No effect of the anisotropy of the sheets on the behaviour in the single connector tests was found. Axial crushing tests of aluminium single-hat sections joined with flow-drill screws were also performed. Two connection failure modes not observed during the single connector test were found in these tests.For comparison, equivalent single connector and component tests were carried out for self-piercing rivet connections. Similar trends with respect to the ductility, maximum force and shape of forcedisplacement curves were observed for the two connections, but the local failure modes were different.

Experimental validation of numerical structural dynamic models for metal plate joining techniques

“…(2016), the macroscopic modeling of flow drill screw connections for static problems is addressed by assessing the ability to capture the behavior of the FDS connections of five state-of-the-art existing FE models for adhesive bonding, spot welding and self-pierce riveting. Together with their previous work (Sønstabø et al., 2015), these analyses are limited to static problems, and the current lack of experimental dynamic testing data for FDS connections in the literature is underlined.…”

Forming a Flanged Hole When Quenching Press-Hardened Steel for Mechanical Fastening

“…Therefore, mechanical fastening is considered an excellent alternative for the mixed-material architectures of lightweight automobiles. Many advanced mechanical fasteners such as self-piercing rivet (SPR) [2] and flow drill screw (FDS) [3] have been studied extensively. Although this technique is advantageous for automation, it necessitates certain constraints on the applicable strength and thickness of the target material.…”

Testing and modelling of flow-drill screw connections under quasi-static loadings

“…Since connections play important roles for the crashworthiness of vehicles, knowledge about their physical behaviour under impact loadings is important for design decisions. Necessary knowledge and physical insight is usually gained through extensive experimental programmes, which typically involve loading specimens consisting of two or more plates joined with one or more connectors until failure (Sønstabø et al, 2015). Various loadings are achieved by changing the specimen design and loading directions.…”

“…Mechanical tests were performed to validate the findings. Sønstabø et al (2015) carried out a large experimental programme to characterize an FDS connection between sheets of AA 6016 T4. The results were compared to equivalent tests on self-piercing rivet connections.…”

“…The results from the process simulation were mapped to finite element models of different coupon tests. The global force-displacement curves from the coupon simulation results were qualitatively compared to corresponding curves from the experiments of Sønstabø and Holmstrøm (2013) which have been presented in the journal article of Sønstabø et al (2015). These experiments were with a different screw and different plate materials.…”