<p>Actual bladed disks with small variations are called mistuned systems. Many researchers suggest that while mistuning has an undesirable effect on the forced response, it has a beneficial (stabilizing) effect on blade flutter (self-excited vibration). Therefore, in designing blades, it is necessary to optimize a bladed disk for forced vibration and blade flutter. In the previous paper, we proposed a simultaneous optimization method of bladed disks for resonant stress of blades and amount of unbalance causing rotor vibration, and the validity of the proposed method was verified by numerical simulations. This study is a follow-up study of the previous study and proposed a simultaneous optimization method of bladed disks for forced and self-excited vibration (blade flutter) considering amount of unbalance. In this method, alternate mistuning is used to suppress the blade flutter. The natural frequency and weight of all blades on a disk are measured, as in the traditional development process. Then, a mistuned system is assembled retaining the alternate mistuning, and the analysis models are generated based on the measured natural frequencies and weights of the blades. Finally, the resonant stress and the amount of unbalance in the mistuned system are analyzed. The analyses of the resonant stress and the amount of unbalance are carried out repeatedly, sorting the blades and retaining the alternate mistuning on the disk, and the simultaneous optimal solution is explored by Monte Carlo simulations or Discrete Differential Evolution (DDE). DDE is an optimization technique based on the genetic algorithm, which can handle discrete or integer variables efficiently. To reduce the computational time, the reduced order model FMM is used to calculate the resonant stress and the stability of mistuned bladed disks. As an example, a mistuned bladed disk of a steam turbine is analyzed and the validity of the proposed method is verified.&nbsp;&nbsp;</p>

Simultaneous Optimization of Mistuned Bladed Disks for Forced and Self-Excited Vibration Considering Amount of Unbalance

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2021/volume/84898

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