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Fragestellung: Die Kontrolle der schnellen, Oberflächen-abhängigen Korrosion von Magnesiumlegierungen ist bisher die größte Herausausforderung biodegradabler Metallimplantate. Daher stellt sich die Frage, ob und mit welchen Techniken offenporige Magnesiumstrukturen mit reduzierter[for full text, please go to the a.m. URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2013)

Joining by electromagnetic forming is a non-contact assembling method that is especially suitable for connections in aluminum space frame structures. By reason of increased joint strength along with lower charging energies, form-fit connections are favored over interference-fit connections for this joining process. In contrast to conventional form-fit concepts, in which the inner joining partner has grooves or pockets, the use of knurled surfaces offers several advantages like easier machinability or the resistance against combined axial and torsional loadings. The objective of this paper is to identify the influencing geometry and process parameters on the joint strength of tubular joints using mandrels with knurled surfaces, with tube and mandrel being made of the same aluminum alloy AA6060-T6. For that reason, experimental studies were conducted: In addition to pull-out tests to determine the axial strength of joints, first computed tomographic images and, afterwards, micrographs of joined components were produced to analyze the contact zone between tube and mandrel and the deformation behavior of the inner joining partner by non-destructive and destructive means. Based on the detailed knowledge of the influencing variables, guidelines for joint and process design are derived.

Based on fundamental technological investigations, alternative joining strategies using electromagnetic forming (EMF) for the flexible production of lightweight frame structures are developed in the collaborative research project SFB/TR10. The results of these investigations will also be used to create general design principles for the joining process itself as well as for the joining zone. The focus of this article will be on dominating form-fit joints of aluminum frame structures and the parameters which have a significant influence on the strength of those joints. For the development of design principles regarding the joining zone, the groove geometry of the connection elements was varied in terms of size and shape, and the influence of those variations was analyzed. In terms of the joining process itself the effect on the joint strength of different forming pressures for a given groove geometry was also investigated. In the first step these experiments were performed on solid mandrels. In order to reduce the weight of the structure, experiments were then performed with hollow connection elements and similar groove geometries to analyze how the reduced stiffness of those elements affected the strength of the joints.