Optimization of the Blade-Dependent Switch Triggers for Reducing Mistuned Bladed Disk Vibration via Piezoelectric-Based Resonance Frequency Detuning

摘要

Turbomachinery bladed disks operate in highly stressed environments and are susceptible to failure induced by high-cycle fatigue. Unavoidable geometric and material variations between blades, referred to as blade mistuning, can confine vibration energy to a small number of blades and cause vibration magnitudes that may be significantly greater than that of the ideal, tuned system. As such, researchers have continually investigated numerous methods to reduce bladed disk vibration. One such method, termed resonance frequency detuning, employs piezoelectric materials to switch between available stiffness states to avoid resonance crossings and reduce vibration. A previous investigation employed RFD to reduce vibration in mistuned bladed disks; however, this investigation only considered a single switch from the open- (high stiffness) to the short-circuit (low stiffness) state. Although decreasing the computational expense and complexity of the analysis, considering only a single switch may not provide optimal performance, specifically for highly mistuned blades. As such, this paper extends the RFD approach by considering multiple switches between the two operating states, thus providing a more complete picture of RFD's performance potential. When considering harmonic excitation, an analytical investigation reveals that for a tuned blisk, there is only a single optimal switch that is primarily a function of the engine-order excitation and the electromechanical coupling; for a mistuned blisk, the optimal switches are blade dependent and primarily functions of the mistuning and the electromechanical coupling. When considering response to transient excitation, RFD requires a separate procedure to identify the optimal switches. This analysis incorporates a genetic algorithm to more rapidly identify these optimal switches that provide the potential for significant vibration reduction performance.