Groove design for form fit joints made by electromagnetic pulse crimping

The electromagnetic pulse process can be an alternative for many conventional production processes. It can be used for perforating, cutting, welding, forming and crimping. In this thesis, the latter will be investigated in detail, with the emphasis on tubular joints bearing axial tension and/or torsion loading. To get acquainted with the subject, first a literature study was performed concerning the general principles of electromagnetic pulse crimping. Because a new field shaper had to be designed, literature on this topic was also consulted. Finally, the design and use of grooves in crimp joints was studied. It has been reported that an inner piece (mandrel) with additional grooves in the joining zone significantly increases the strength of a crimped joint [1]. However, the information on electromagnetic pulse crimping with a mandrel with more than one groove is very limited. Therefore one of the main goals of this thesis is to determine an optimal design for a mandrel with two grooves used for axially loaded joints. A combination of finite element simulations and experiments was used to draw preliminary conclusions involving the double groove design. In a later stage torsional joints will be designed and suitable filler materials to realize leak proof joints will be evaluated.The electromagnetic pulse process can be an alternative for many conventional production processes. It can be used for perforating, cutting, welding, forming and crimping. In this thesis, the latter will be investigated in detail, with the emphasis on tubular joints bearing axial tension and/or torsion loading. To get acquainted with the subject, first a literature study was performed concerning the general principles of electromagnetic pulse crimping. Because a new field shaper had to be designed, literature on this topic was also consulted. Finally, the design and use of grooves in crimp joints was studied. It has been reported that an inner piece (mandrel) with additional grooves in the joining zone significantly increases the strength of a crimped joint [1]. However, the information on electromagnetic pulse crimping with a mandrel with more than one groove is very limited. Therefore one of the main goals of this thesis is to determine an optimal design for a mandrel with two grooves used for axially loaded joints. A combination of finite element simulations and experiments was used to draw preliminary conclusions involving the double groove design. In a later stage torsional joints will be designed and suitable filler materials to realize leak proof joints will be evaluated.C