Environmental Engineering Reference
In-Depth Information
In preliminary tests, a blade system damping ratio of 0.010 was measured, which was
somewhat higher than a reference value of 0.006 for composite structures [White 2004].
Compared to dual forced-displacement, testing speed was increased from 0.30 Hz to 0.75 Hz
and hydraulic flow was reduced by 50 percent, from 200 gallons per minute (gpm) to 100
gpm. These tests confirmed the expected advantages of the hybrid system, leading to shorter
test times and reduced energy consumption during testing.
Figure 12-25. Schematic elevation view of a wind turbine blade in a dual-axis hybrid test
facility, in which flatwise loads are applied by the resonance method and edgewise loads
(not shown) are applied by the force-displacement method.
An excitation mass mounted on
the blade oscillates vertically at the blade's flatwise fundamental natural frequency, driven by a
small hydraulic actuator. [White 2004]
Search WWH ::
Custom Search