Abstrakt
The steam turbine blades of low pressure stages are endangerd by the
high-cyclic fatigue due to the combined loading of dynamic stresses by the
steam time-variant pressure and the pre-stress from centrifugal forces.
Therefore, the importance of their experimental dynamic analysis in the
design stage is critical. For laboratory tests of the blades, the piezo
actuators placed on the blades, unlike electromagnets placed in the
stationary space, give a possibility to excite the flexural vibration of
the blades within the bladed disk by time continuous forces independently
of the rotor revolutions. In addition, the piezo actuators can be also
used to control the vibrations of the blade. Therefore, several dynamic
experiments of the clamped model blade equipped with PVDF films were
performed for the force description of the piezo foils and their behavior
as actuators of the blade vibration. The numerical beam models were used
for numerical analysis of the vibration suppression effects both by
additional parametric excitation and by active damping. The optimal phase
shift of piezo actuator voltage supply was ascertained both for amplitude
amplification and suppression. The results contribute to the knowledge of
the actuation and active damping of blade vibration by the piezo elements
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