Influence of groove characteristics on strength of form-fit joints

Joining by electromagnetic forming (EMF) is an innovative method to connect, e.g. extruded aluminum profiles to lightweight frame structures without heating or penetrating the profile. This article describes the joining of extruded aluminum profiles by electromagnetic forming, taking into account the process characteristics and the joint design. Forming is initiated by a magnetic impulse of high energy density, such that material with high electrical conductivity is deformed by Lorentz forces. With this high-speed forming process high-strength joints can be manufactured as interference fits, form fits, impact welded joints or a combination of these types. The focus of this paper is on form-fit joints of extruded aluminum profiles for lightweight frame structures. Based on fundamental technological investigations the parameters which specifically affect the strength of the joints were identified and analyzed. Throughout these experiments the groove geometry was varied size and shape wise. The influence of the acting magnetic pressure and the charging energy on the joint strength was also analyzed for the various groove geometries.