This paper shows a numerical and experimental analysis of the different problems occurring during or after the conventional self-pierce riveting with semi-tubular and solid rivets of the high strength aluminum alloy E...
This paper shows a numerical and experimental analysis of the different problems occurring during or after the conventional self-pierce riveting with semi-tubular and solid rivets of the high strength aluminum alloy EN AW-7021 T4. Furthermore this paper describes different pre-process methods by which the fracture in the high strength aluminum, caused by the self-pierce riveting processes, can be prevented and proper joining results are achieved. On this basis, the different approaches are compared regarding joint strength.
Car body manufacturing begins with sheet metal forming, while in subsequent steps the inner structures of the vehicle are assembled and connected to the outer skin by hemming. The use of FEM (finite element method) to...
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Hot stamping is an important technology for manufacturing high-strength components. This technology offers the possibility to achieve significant weight reductions. In this study, cushion-ram pulsation (CRP), a new te...
Hot stamping is an important technology for manufacturing high-strength components. This technology offers the possibility to achieve significant weight reductions. In this study, cushion-ram pulsation (CRP), a new technology for hot stamping on servo-screw presses, was investigated and applied for hot stamping. Compared to a conventional process, the tests yielded a significantly higher drawing depth. In this paper, the CRP technology and the first test results with hot stamping were described in comparison to the conventional process.
In contrast to common and classical joining technologies for composite/metal hybrid structures such as bonding and riveting, profile and contour joints offer a promising potential for novel lightweight hybrid structur...
In contrast to common and classical joining technologies for composite/metal hybrid structures such as bonding and riveting, profile and contour joints offer a promising potential for novel lightweight hybrid structures. First and foremost, joining systems with a form closure function enable to pass very high loads into rod- and tube-shaped fibre reinforced structures and achieve high degrees of material utilization for the composite part. This paper demonstrates the theoretical and technological principals for a resource efficient design and production of highly loaded thermoplastic composite profile structures with integrated metallic load introduction elements and a multi scale form closure. The hybrid structures are produced in an integral blow moulding process in which a braided tape-preform is simultaneously consolidated and formed into the metallic load introduction element. These metallic load introduction elements are manufactured in a two-stage process of external and internal hydroforming, after forming simulations have assured process stability for consistent quality.
The shape memory alloy NiTi has successfully proved in many areas of medical technology. This paper describes the innovative idea and development of orbital floor implants made of NiTi. Pseudoelastic NiTi has the pecu...
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The shape memory alloy NiTi has successfully proved in many areas of medical technology. This paper describes the innovative idea and development of orbital floor implants made of NiTi. Pseudoelastic NiTi has the peculiarity to withstand large mechanical deformations of up to 8% without being plastically deformed, i.e. it returns to its original shape with relief of the strain. This material property can be used to produce flexible, yet stable implants. The NiTi implants can be implanted into the body in compressed form through relatively small approaches. Arriving at the fracture position, they develop self-reliantly in the previously memorized shape. The perioperative trauma is reduced. The treatment of orbital floor fractures is often done surgically by use of implants made of rigid materials such as titanium, which are inserted in the eye socket through an open approach on the lower eyelid. Implants made of a pseudoelastic shape memory alloys can help to reduce the required incision length of the approach. It is even possible to insert the implant in a minimally invasive procedure via endoscopic access routes and to completely avoid open approach. In this paper first design variants of pseudoelastic orbital floor implants are presented and considerations on the manufacturing process are made.
In the present work, the influence of the additions of zinc, zirconium and cerium-rich mischmetal on the microstructural recrystallization development of magnesium were investigated. Grain size and chemical compositio...
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In the present work, the influence of the additions of zinc, zirconium and cerium-rich mischmetal on the microstructural recrystallization development of magnesium were investigated. Grain size and chemical composition were the principal variables of the billets used for indirect extrusion experiments. Significant changes in the evolution of the dynamic recrystallization (DRX) process as a function of the alloying element contents and the process variables were observed. Microstructures and preferred orientation of crystallites were correlated in order to discuss the role of alloy composition on the DRX. This discussion was based on the macro-texture measurements and some EBSD measurements of selected samples.
Simulation, design optimization and controller design of modern machinetools heavily rely on adequat numerical models. In order to achieve results in shorter computation times, reduced order models (ROMs) are applied...
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