posted on 2006-10-10, 10:14authored byThomas Eck, Stephen Walsh, Jane Horner
Moment excitation is often neglected in structural vibration analysis due to difficulties in
measuring the applied moment and the resulting wave motion in the structure. Further, it is
often assumed that moment induced vibrational energy is only significant in the high
frequency region. However, recent studies have shown that moment excitation should be
included in vibrational analysis at all frequencies when the source location is in close
proximity to a structural discontinuity. In this paper a novel method is presented to measure the point mobility and
resulting vibrational energy of a beam subjected to moment excitation. The proposed
method utilises a finite difference approximation to calculate the rotational motion of the
beam at the point of excitation. Moment excitation is induced by a specially designed
impact rig which applies two equal and opposite forces on two moment arms that are perpendicularly attached to the beam. It is shown that, using the newly developed
technique, the measured point mobility follows the trend of the equivalent theoretical
structure. The technique also showed good agreement over a wide frequency range
between the measured input energy and measured transmitted flexural wave energy along
the beam.
History
School
Aeronautical, Automotive, Chemical and Materials Engineering
Department
Aeronautical and Automotive Engineering
Pages
428916 bytes
Citation
ECK, T., WALSH, S.J. and HORNER, J.L., 2006. Measurement of vibrational energy and point mobility of a beam subjected to moment excitation using a finite difference approximation. IN: Proceedings of the IMechE Part C: Journal of Mechanical Engineering, 220(6), pp. 795-806