ISSN:
1662-7482
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The ISO 6267 standard defines a damping measuring method in terms of the half-time ofthe vibration of clamped alpine skis that is mainly related to the first vibration mode only. By meansof the experimental test done in laboratory, it is shown that this method is not able to completelycharacterize the damping of the skis that depends on the vibration mode considered. For example inthe case a ski sample, damping ratio varies from 0.45%±0.05% of the first mode to 2.1%±0.1% ofthe fourth one.The experimental test done on ski tracks by means of piezo-accelerometers placed on the skisrunning at speed of 12.5 m/s showed that the skis vibrate according to a combination of at least thefirst 4 vibration modes and that the snow better excites frequencies greater than the first one.As the excitation frequencies on the skis during the descent are much higher than the first naturalfrequency of the ski, it appears not correct to hypothesize that only the damping coefficient relativeto the first natural frequency is representative of the ski vibrations.To improve the UNI ISO 6267 standard, a new method based on the Fourier Transform filteringto separate the time history into the vibration components is proposed for the characterization of theski damping that is variable with its natural modes
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/39/transtech_doi~10.4028%252Fwww.scientific.net%252FAMM.5-6.199.pdf
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