Experimental Investigation of a Flexible Airframe Taxiing Over an
Uneven Runway for Aircraft Vibration Testing 01-17-02-0013
This also appears in
SAE International Journal of Aerospace-V133-1EJ
The ground vibration test (GVT) is an important phase in a new aircraft
development program, or the structural modification of a certified aircraft, to
experimentally determine the structural vibrational modes of the aircraft and
their modal parameters. These modal parameters are used to validate and
correlate the dynamic finite element model of the aircraft to predict potential
structural instabilities (such as flutter), assessing the significance of
modifications to research vehicles by comparing the modal data before and after
the modification and helping to resolve in-flight anomalies. Due to the high
cost and the extensive preparations of such tests, a new method of vibration
testing called the taxi vibration test (TVT) rooted in operational modal
analysis (OMA) was recently proposed and investigated as an alternative method
to conventional GVT. In this investigation, an experimental setup was
constructed to further investigate the applicability of the TVT to flexible
airframes encountered in fixed-wing autonomous aerial systems with
oleo-pneumatic shock absorber landing gears in a tricycle configuration. The
influence of the taxiing speed and the landing gear–shock absorber damping
setting on the outcome of the TVT is also investigated. The taxiing speed was
found to strongly influence the success of the test with an optimal taxiing
speed existing for the assembled airframe that allows for the best TVT outcome.
The shock absorber damping setting was found to increase the level of the
airframe excitation during the TVT; however, it did not impact its outcome as
compared to the taxiing speed. Certain modes were not identified during the TVT
tests, which was attributed to the way the assembled aircraft is secured to the
moving belt and to the lack of sufficient excitation through taxiing. The
experimental vibrational modes were successfully matched against the modes
obtained from the normal modal analysis of an uncorrelated flexible multibody
dynamics model. Further investigations are suggested before the TVT method can
be deemed suitable for all classes of fixed-wing aerial systems.
Citation: Al-bess, L. and Khouli, F., "Experimental Investigation of a Flexible Airframe Taxiing Over an Uneven Runway for Aircraft Vibration Testing," SAE Int. J. Aerosp. 17(2):2024, https://doi.org/10.4271/01-17-02-0013. Download Citation
Author(s):
Lohay Al-bess, Fidel Khouli
Affiliated:
Carleton University, Department of Mechanical & Aerospace
Engineering, Canada
Pages: 22
ISSN:
1946-3855
e-ISSN:
1946-3901
Related Topics:
Aircraft certification
Finite element analysis
Vehicle dynamics
Landing gear
Dampers and shock absorbers
Fixed-wing aircraft
Aerodynamics
Vibration
Test procedures
Unmanned aerial vehicles
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