Heinz Leitner

Schädigungstolerante Auslegung von Aluminium-Druckgusskomponenten

Kurzfassung Für eine verbesserte betriebsfeste Auslegung von Aluminium-Druck-Kurzfassung gussbauteilen muss die Porenverteilung im Bauteil abgeschätzt werden können. Ein existierendes Porositätsmodell wurde für die Berechnung der Porenverteilung in einem Referenzbauteil verwendet. Ein Vergleich mit der Porenverteilung im realen Bauteil zeigt eine sehr gute Übereinstimmung. Der Einfluss der Poren auf die Schwingfestigkeit wird anhand des Kitagawa-Diagramms beschrieben. Daraus kann, zusammen mit der Porenverteilung im Bauteil, die lokal ertragbare Spannungsamplitude abgeleitet werden.

Four Point Bending Fatigue Tests of Forged Ti 6Al 4V

Abstract The paper derives from a long-term research program that is aimed at developing qualitative and quantitative design guidelines to influence mechanical surface treatments in order to improve the fatigue life of structural components. A four point bending test rig was developed using finite element analysis. High cycle fatigue tests were performed on plane specimens taken from Ti 6Al 4V forgings with mill-annealed or bimodal microstructure. The high cycle fatigue behaviour of specimens with two different surface conditions (as-forged and machined) was compared. In order to assess the fatigue failure mechanisms, detailed investigations of the surface layer were carried out. Residual stresses were shown to play an important role in fatigue.

The influence of welding process parameters on residual stresses by means of coupled thermo-mechanical simulation

To achieve an accurate lifetime assessment based on welded joints, the value of the effective notch stress by means of local approaches has to be determined. Moreover, detailed knowledge of the local material properties at the complex thermo-mechanical welding process must be available. Hence, a special challenge in the knowledge of local conditions must be performed. The impact of the welding process, e.g., by change of the heat-affected-zone, conducts the local residual stress distribution as well as the restraining boundary condition. The significance of the specimen clamping condition was shown by strain gauge measurements. The need of a local thermo-mechanical coupled simulation model is given especially in the case of strain-based interacting weld seams. The size and shape of the heat-affected-zone was verified by metallographic investigations. Finally, a fatigue life calculation based on the structural stress approach was done.

Influence of Rolling Reduction on Fatigue Behaviour of AA6016/FeP06 Material Compound

The goal of this research project is the development of a simulation model for lifetime estimation of components manufactured from the AA6016-T4/FeP06 material compound. Components composed of this material are manufactured predominantly by rolling and deepdrawing. For this reason, the influence of the plastic deformations during the manufacturing process on the fatigue behaviour must be investigated. Particularly the cyclic hardening behaviour of FeP06 steel has a relevant effect on the fatigue life of this aluminium-steel compound. Simulation models for fatigue life estimation therefore have to consider the influence of this hardening effect, which occurs during the manufacturing process. In this work, test results and a simulation model to take into account the influence of the rolling reduction on the fatigue behaviour of components manufactured from the AA6016/FeP06 material compound are presented.

The Influence of Temperature and Pre-Aging on the Low Cycle Fatigue Behaviour of Nickel Coatings (Ni 200/201)

Nickels are generally used for thermal barrier coatings, with their function of extending fatigue life. Nevertheless the thermal cyclic loading often takes place in the low cycle fatigue (LCF) region [1], become the process are driven by cyclic plasticity. Therefore it is necessary to study the low cycle fatigue behaviour of Ni 200/201, as shown in Fig. 1, according to Manson-Coffin-Basquin law [2, 4].

Oberflächenbehandlung durch Kugelstrahlen und Festwalzen

Kurzfassung Das Potenzial von Oberflächenverfestigungsverfahren zur Schwingfestigkeitserhöhung wird untersucht. Dazu werden Simulationsmodelle zur Beschreibung der mechanischen Oberflächenverfestigungsverfahren Kugelstrahlen und Festwalzen vorgestellt und durch Versuchsergebnisse verifiziert. Auf Basis spannungs- und bruchmechanischer Ansätze werden durch Oberflächenbehandlungen eingebrachte Eigenspannungen sowie herstellungsbedingte Bauteilfehler hinsichtlich ihrer Auswirkungen auf die Betriebsfestigkeit bewertet.

New Gear Manufacturing Technologies in the Automotive Field of Transmissions, Axle Drives and Transfer Cases

Thanks to its innovative products in the field of all-wheel drives, Magna Powertrain (MPT) has positioned itself in manufacturing high-performance All wheel drive gearboxes in the worldwide market very well. The continuity of the overall development process from manufacturing via assembly to comprehensive performance checks with integration in the vehicle is decisive for MPT’s system competence. In order to meet the customers’ requirements even in future, it is, in the long run, not only necessary to provide innovations that are relevant to the function. It also is absolutely required to enable optimizations based on innovative manufacturing concepts and methods will be done by innovative material selection, new manufacturing process chains or in their combination. Today the degree of optimization of machining, which is used for manufacturing gearing, is already very high. Therefore, advantages relating to manufacturing technology can only be achieved by completely changing the manufacturing concept. It is a matter of massive forming processes, which are particularly suitable as pre-processes or finishing processes for such gearing. Such terms as “Net shape” or “Near net shape” have been already integrated in literature for describing these manufacturing processes. Hot forming, semi-hot-forming or cold forming processes or their combination can be used depending on the geometrical requirements to achieve these near-net shape- or net shape condition. For slightly loaded, slow-rolling-off gear pairs, this process already is state of the art in many cases. In the field of highly loaded fast-rolling-off-involute cylindrical gears, we are entering new territory, no matter whether it is a question of all-wheel drive gear boxes, automatic or manual transmissions or of applications in the engine. The requirements placed on fatigue strength and gearing noise are correspondingly high for such gearing. This is a particular challenge both for innovative manufacturing technology and the design and test programme. In this paper you were shown about the status of current predevelopment programs regarding manufacturing of toothing for high speed gears.Copyright