Improved Strain-Energy Based Mistuning Models - Part II: Understanding the Mistuned Blade Response for a Non-Isolated Family of Modes

Abstract The second part of the two-part paper describes the impact of the improved strain energy-based model on the mistuned blade response of a non-isolated mode family. This paper concentrates on coupling aerodynamic and structural dynamics into the FMM method to improve the accuracy of the mistuned prediction, especially in the “veering” region. The current paper extends part I of this study and describes in detail the impact of modelling a different strain energy at every ND and calibrates the non-dimensional strain energy parameters against experimental data. The paper also describes the impact of different mistuning models on the mistuning amplification factors for the Purdue 3 stage compressor rotor 2. The second part of the paper provides assessment of these strain energy-based models on the sensitivity of the mistuned forced response predictions with a perturbation in the system mode frequency. Lastly, the paper describes the impact of mistuning model on the aerodamping predictions. The key conclusions are: 1) The improved strain energy formulations lead to a significant improvement in the mistuning amplification factor for a non-isolated mode family, and 2) Perturbing the system mode frequency of a single ND has a significant impact on the mistuning amplification factor and is dependent on the mistuning model of choice.