Experimental Monte Carlo Mistuning Assessment of Bladed Disk Vibration Using Forcing Variations

It is known that the vibration response of bladed disks in turbine engine rotors can be extremely sensitive to small, random blade-to-blade variations, or mistuning. However, it is cumbersome to assess the eects of random mistuning or validate numerical predictions for a population of mistuned bladed disks using experimental methods. In this work, as an alternative approach for performing vibration testing of many mistuning patterns, it is proposed that varying the external forcing function provided to the blades can be used to mimic the influence of structural blade property mistuning on the vibration response. Because it is much easier and more ecient to vary the external excitation than to physically alter the blades, this opens the possibility of running an experimental analog of a Monte Carlo simulation. This approach, referred to as an experimental Monte Carlo mistuning assessment, is explored and validated by comparing simulations and test data for a 24bladed disk. The experimental Monte Carlo results are found to have excellent agreement with numerical Monte Carlo simulation results for a case of small standard deviation of mistuning.