Electromagnetic pulse crimping of axial form fit joints

Abstract

Electromagnetic pulse crimping of form fit joints was investigated using tubes in the aluminium alloy EN AW-6060, with a diameter of 50 mm and a wall thickness of 1,5 mm. First the influence of the charging voltage and the geometrical groove parameters on the deformation behaviour and localised thickness reduction of the tube wall was investigated. The experimental results provided data for optimising the groove design. The Design of Experiments method was used to optimise the shape and dimensions of the internal workpieces with a double groove design. Results of tensile tests on the crimp joints allowed determining the most important parameters for the groove design. Based on these observations an optimal double groove joint design was proposed. The deformation and failure behaviour of the crimp joints during tensile testing were experimentally studied using the digital image correlation technique. This technique was used to measure the local and global deformation of the joint. Failure mechanisms include pull-out, local shearing and fracture of the tube. Three main failure modes were observed.