Random Vibrations of Bladed-Disk Assemblies Under Cyclostationary Excitation

Random vibration of bladed-disk assemblies is studied. The blade excitation is modeled as a nonstationary random process whose statistics vary periodically in time. To the best Of our knowledge, this is the first stochastic model that accounts for the unsteadiness of the turbulent forces applied to the blades. It is shown that a conventional approach, which treats the blade excitation as a stationary process, is likely to underestimate the response of the blades. Moreover, the amplitude of the nonstationary random part of the response is found to be comparable to the deterministic part. Consequently, it is important to model the flow around the blades as a nonstationary stochastic process.