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Stuttgart, Germany

Dollinger C.,Bremen Institute for Metrology | Balaresque N.,WindGuard GmbH | Sorg M.,Bremen Institute for Metrology
European Wind Energy Association Conference and Exhibition 2014, EWEA 2014 | Year: 2014

The location of the laminar-turbulent transition has a direct effect on the performance of an airfoil. Thermography has been a valuable tool for boundary layer visualisation for several years in both wind tunnels and other applications. The use of high-speed and high sensitivity thermal imaging systems in combination with long focal length lenses allows applying this method to megawatt (MW) range wind turbines in operation, in which the investigated rotorblade and the measurement position are several hundred meters apart. Preliminary measurements deliver qualitative information regarding the transition location along the rotorblade, and allow comparisons between different operational states and conditions. In this article first results for a thermographic boundary layer visualisation of wind turbine rotorblades in operation are presented. The measurements were performed on a 2 MW AN-Bonus wind turbine and the research wind turbine of the University of Bremen, Germany (REpowera 3.4 M104 with 128 hub-height). Source


Meyer D.,IWT - Foundation Institute of Materials Engineering | Kruse D.,Bremen Institute for Metrology | Bobe A.,IWT - Foundation Institute of Materials Engineering | Goch G.,Bremen Institute for Metrology | Brinksmeier E.,IWT - Foundation Institute of Materials Engineering
Production Engineering | Year: 2010

Nondestructive characterization of surface and subsurface properties is of increasing interest in industry and science. As destructive methods are inadequate for testing large devices (e.g. gear wheels for wind engines) or small series, nondestructive techniques for the assessment of their surface integrity are mandatory. Especially surface hardened components have to be examined in practice, as they tend to show varying properties regarding surface hardness, hardness penetration depth and residual stress profiles. Since the surface integrity has a major influence on the functional performance of components, assessment and monitoring of the surface properties is crucial. In this study, the results of a new technique for surface hardening (cold surface hardening) were investigated for the first time applying an emerging nondestructive measuring method: the photothermal near-surface layer characterization. © 2010 German Academic Society for Production Engineering (WGP). Source


Beekhuis B.,IWT - Foundation Institute of Materials Engineering | Stobener D.,Bremen Institute for Metrology | Brinksmeier E.,IWT - Foundation Institute of Materials Engineering | Goch G.,Bremen Institute for Metrology
Materialwissenschaft und Werkstofftechnik | Year: 2012

During soft-turning of rings, both, deviation of the wall thickness and the shape occur. Additionally, further changes of shape result from the subsequent heat treatment. To ensure desired geometric tolerances, a high stock allowance for finishing is necessary. Geometric deviations of machined rings originate mainly from workpiece clamping during the machining process due to elastic deformation. Therefore, several special clamping devices are applied in industry to reduce workpiece deformation. But the choice of chucks is always a trade-off between high flexibility and low part distortion. To ensure minimal part distortion in spite of using flexible clamping devices, clamping strategies and novel dynamical turning processes have been developed. Dynamical adapting of the depth of cut based on the measurement of geometric errors, is realized by using a tool actuator combined with an in-process ultrasonic measurement system. This paper discusses the compensation potential of developed methods to reduce part distortion. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Zhang P.,Bremen Institute for Metrology | Renken V.,Bremen Institute for Metrology | Goch G.,Bremen Institute for Metrology
Materialwissenschaft und Werkstofftechnik | Year: 2012

This contribution reports on a cross-plane quality control concept for the production of bearing rings. The principal part of this quality control concept is the cross-plane controller, which actually acts as an iterative optimization throughout the production chain and bases upon the models of each sub-process. The cross-plane controller and a model-based sub-control system for the gas quenching process are introduced in this paper. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Patzelt S.,Bremen Institute for Metrology | Pils K.,Bremen Institute for Metrology | Tausendfreund A.,Bremen Institute for Metrology | Goch G.,Bremen Institute for Metrology
Proceedings of the 12th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2012 | Year: 2012

Scattered light speckle techniques enable absolute and high resolution position measurement without the requirement for a special length scale standard. A compact measuring probe set-up and low manufacturing costs qualify it for the integration into machine tools and assembly lines. The contribution focuses on the measuring resolution enhancement and presents the measuring process and first results. Source

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