Design of Electromagnetic Pulse Crimp Torque Joints

Abstract

Electromagnetic pulse crimping of form fit joints was investigated using tubes with a diameter of 50 mm and a wall thickness of 1,5 mm, in the aluminium alloy EN AW-6060. The tubes were crimped onto steel internal parts, which were designed to bear torsional loads. Grooved, knurl rolled and knurl cut internal workpieces were used. To assess the torque strength of the connections, a torque test set-up was designed and built. In a first test series, grooved internal parts were used. The influence of the internal workpiece design and the energy level on the torque resistance was investigated. Related to the geometry of the internal workpiece, the following parameters were varied: the groove depth, the groove width, the edge radius and the number of grooves. In a second test series, knurl rolled and knurl cut internal workpieces were used. For the joints with a knurl rolled internal part, the influence of the knurl pattern, defined by the pitch, was investigated. For the connections with a knurl cut internal part, the influence of the energy level was studied. The different joint failure mechanisms were determined.