The vibration analysis of a bladed disk in a turbine engine rotor can be conducted relatively easily if it is assumed that each sector of a bladed disk in a turbine engine rotor is identical because cyclic symmetry can be employed. In reality, however, there are unavoidable small differences among the structural properties or geometric characteristics between individual blades due to manufacturing tolerances, material deviations, and non-uniform operational wear. These small and random differences are commonly referred to as mistuning. Even though mistuning is typically small in terms of individual blade properties, this small mistuning can have dramatic effects on the forced responses. Namely, mistuning can cause localization of vibration to a few blades of the bladed disk which can lead to drastic increases of amplitudes of blade responses.

In actual operating conditions, the blades of a turbine engine rotor always experience interaction with flows, therefore the bladed disks also exhibit aerodynamic coupling in addition to structural coupling. This aerodynamic coupling causes the system to have aerodynamic stiffness and damping, which can affect the stability of the system by changing both the free and forced responses of the bladed disk. Thus, aeroelastic calculations are necessary in addition to structural calculations for predicting accurately the vibration characteristics of bladed disks.

We currently focus on the aeroelasticity of mistuned multi-stage bladed disks, and an efficient reduced-order modeling method which considers unsteady aerodynamic forces has been developed. We also explore the aeroelasticity of mistuned single-stage bladed disks with damage such as cracks.

Aeroelasticity of Multi-stage Turbine Engine Rotors

Aeroelasticity of Single-stage Turbine Engine Rotors with cracks