The accuracy of numerical simulation models for forming processes depends highly on the method for the flow curve determination. Numerous experimental tests exist to identify the flow curves of sheet metals, each with...
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The accuracy of numerical simulation models for forming processes depends highly on the method for the flow curve determination. Numerous experimental tests exist to identify the flow curves of sheet metals, each with certain characteristics regarding stress states and achievable strains. In this paper stress state analysis are presented for the mechanical joining techniques clinching as well as self-pierce riveting with semi-tubular rivet (SPR). Based on these findings flow curves for DC04 material are determined by selected experimental materials tests in order to compare the influence of the flow curve determination method on the accuracy of the process simulation models.
Lattice structures are highly recommended as lightweight components. But until now, parts with lattice structures are mainly used for illustrative purposes. This is because their modelling, dimensioning, and build pre...
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Electromagnetic pulse welding is an innovative technology suitable for joining various similar and dissimilar tube and sheet metal parts including dissimilar material combinations, which are difficult to join by conve...
Electromagnetic pulse welding is an innovative technology suitable for joining various similar and dissimilar tube and sheet metal parts including dissimilar material combinations, which are difficult to join by conventional, i.e. thermal welding methods. In case of proper choice of process parameters, a high joint quality can be achieved. In literature this is often demonstrated by failure in the base material during destructive testing. However, no standard testing procedures for magnetic pulse welded joints have been agreed on and thus industrial implementation is severely complicated. Specifically, investigations regarding non-destructive testing are rarely available. The paper evaluates different testing and characterization methods. Specifically, metallographic analysis and lap shear tests are taken into consideration. Finally, Laser UltraSound (LUS) is presented as a new alternative for characterizing magnetic pulse welded joints. The technique is based on measuring laser ultrasound waves which are either transmitted through or reflected by the weld seam. A comparison of the results to those of the more established destructive testing methods shows, that LUS measurements absolutely allow qualitative and quantitative conclusions regarding weld quality. Due to high automation potential, the method is a promising alternative for quality control in industrial manufacturing.
In contrast to common and classical joining technologies for composite metal hybrid structures such as bonding and riveting, profile and contour joints offer promising potential for novel lightweight structures. First...
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For the application of spark erosion in micro- and precision manufacturing, it is particularly important that small structures with small spark gaps can be machined in the range of a few micrometers. Due to the applic...
For the application of spark erosion in micro- and precision manufacturing, it is particularly important that small structures with small spark gaps can be machined in the range of a few micrometers. Due to the application of an additional high- dynamic piezo positioning system, smaller feed steps can be implemented which ensure a higher process stability. This additional feed system can be adapted to existing feed systems, whereby the process variable to be influenced is the spark gap. The primary feed system does not have to be directly influenced. The article shows how the structures of parallel regulation circuits for such operating piezo positioning systems are constructed and how they can improve the productivity, the machining accuracy and the surface quality. A selected example shows how the structural design of the highly dynamic system can be designed for different process parameters of industrial basic systems.
The paper shows experimental and numerical analyses of the clinching process of 6xxx series aluminum sheets in T6 condition and the self-pierce riveting process of an aluminum die casting. In the experimental investig...
The paper shows experimental and numerical analyses of the clinching process of 6xxx series aluminum sheets in T6 condition and the self-pierce riveting process of an aluminum die casting. In the experimental investigations the damage behavior of the materials when using different tool parameters is analyzed. The focus of the numerical investigations is the damage prediction by a comparison of different damage criteria. Moreover, strength-and fatigue tests were carried out to investigate the influence of the joining process-induced damages on the strength properties of the joints.
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