[Back]

H. Ecker, T. Pumhössel:
"Experimental results on parametric excitation damping of an axially loaded cantilever beam";
in: "Proceedings 2009 ASME International Design Engineering Technical Conferences", issued by: ASME; ASME, 2009, ISBN: 978-0-7918-3856-3, Paper ID DETC2009-86555, 10 pages.

In various fields of engineering, e.g. aerospace applications,
robotics or the bladings of turbomachinery, slender beam-like
structures are in use and subject to free bending vibrations. Since
such vibrations often are not wanted because they may degrade
the performance or function of the structure, it is important to
have a suitable means of vibration suppression available.
In this experimental study we investigate a slender cantilever
beam loaded with a controlled force at its tip. The force is always
oriented towards the clamping point of the beam and generated
by a piezo-actuator. Force control is based on an open-loop control
without feedback from the structure. To enhance vibration
suppression we take advantage of the additional damping observed
when a periodic force modulation at a certain frequency
is applied. From several theoretical studies it is known that parametrically
excited systems show increased stability, and therefore
enhanced damping properties, when the parametric excitation
frequency is chosen near a certain combination frequency.
Due to the almost axially applied force the cantilever beam system
becomes a parametrically excited system and the effect mentioned
can be observed.
Numerous measurement runs have been carried out and vibration
suppression as a function of the excitation frequency, the
excitation amplitude and the beam initial deflection has been investigated.
The results are in very good agreement with theoretical
predictions and for the first time the numerical and analytical
results obtained earlier are confirmed by experimental work.