Keeping on the right track

ICE trains travel at speeds of up to 300 kilometers per hour, subjecting the wheels to considerable load. To detect possible damage at an early stage, Fraunhofer researchers have developed new ultrasound and laser testing systems.

On straight stretches of rail track, an ICE travels faster than a jet in takeoff. The wheels of an Intercity Express are subjected to considerable stresses. Wheelsets have to be inspected regularly to detect defects at an early stage. Until now, this safety check was time-consuming and personnel-intensive: Teams of engineers inspect the wheels for possible defects and measure the diameter and profile. At predefined maintenance intervals, the wheelsets are dismantled, their profiles reground, and the material tested for defects using ultrasound equipment.
The new testing systems, developed by researchers of three Fraunhofer Institutes working closely with the Deutsche Bahn, save valuable time: The laser optical inspection of ICE wheels reveals the wear on a wheelset while the train slowly rolls over a measuring station integrated in the rails. Lasers project a pattern of lines onto the rolling surface of the wheels. Cameras record this pattern and convey it to an analysis system that calculates the profile of the contact surface and the wheel diameter. The system has meanwhile been installed at nine locations worldwide, and not only provides fast and accurate results, but is also robust enough to withstand rough handling and any weather conditions, explains Dara Fatehi-Varkani of the Fraunhofer Institute for Production Systems and Design Technology IPK in Berlin.
Another time-saving invention is the underfloor wheelset inspection unit developed by an interdisciplinary research team from the Fraunhofer Institute for Non-Destructive Testing IZFP in Saarbrücken and the Fraunhofer Technology Development Group TEG in Stuttgart. The Deutsche Bahn is already using three of these systems, which permit ultrasound inspection without having to dismount the wheelsets. The mobile test units are driven up to the ICEs wheels from below. Software developed by the IZFP provides graphical output of the measured data within seconds, allowing the inspector to evaluate the wheel quality. Joachim Montnacher, an engineer at the TEG: The systems advantage is its flexibility. It can be adjusted to suit different types of train. The ultrasound system analyzes the state of the wheel interior and its surface. By contrast, laser inspection reveals the wear on the wheel profile. The two systems therefore superbly complement one other. Joachim Montnacher and Jürgen Goetz of the TEG, Bernd Rockstroh and Wolfgang Kappes of the IZFP, and Dara Fatehi-Varkani of the IPK, shared the Joseph-von-Fraunhofer prize for special merit.,Joseph-von-Fraunhofer Prize - research with a practical orientation
This prize has been awarded by the Fraunhofer-Gesellschaft every year since 1978, in recognition of outstanding scientific work by members of its staff leading to the solution of application-oriented problems. Over 200 researchers have meanwhile seen their work honored in this way. This year - for the 25th time -, three regular prizes were awarded - each valued at 10,000 euros. The additional prize for special merit is worth 20,000 euros.,For further information:,Dipl.-Ing. Bernd Rockstroh ,Telefon: [phone] ,Fax: +49/ 6 81 / 93 02-59 04 ,E-mail: [e-mail]
Fraunhofer-Institut fur Zerstorungsfreie Prufverfahren IZFP ,http://www.izfp.fraunhofer.de/
Dipl.-Ing. Joachim Montnacher ,Telefon: [phone] ,Fax: [phone] ,E-mail: [e-mail]
Fraunhofer-Technologie- Entwicklungsgruppe TEG ,http://www.teg.fraunhofer.de/
Dipl.-Ing. Dara Fatehi-Varkani ,Telefon: [phone] ,Fax: [phone] ,E-mail: [e-mail]
Fraunhofer-Institut fur Produktionsanlagen und Konstruktionstechnik IPK ,http://www.ipk.fraunhofer.de/willkommen.html
Link: ,Presseinformation 2001 ,http://www.fraunhofer.de/german/press/pi/pi2001/index-pi28-2001-t.html

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