Prediction of Flutter Stability Using Aeroelastic Frequency Response Functions

✍ Scribed by M. Imregun

• Book ID: 102971783
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 501 KB
• Volume: 9
• Category: Article
• ISSN: 0889-9746
• DOI: 10.1006/jfls.1995.1024

✦ Synopsis

This paper deals with the flutter stability of turbomachinery blading using aeroelastic frequency response functions (FRFs) which are obtained by inverting the dynamic stiffness matrix of the aeroelastic system. The structural model is a lumped parameter representation while the aerodynamic model is based on linearized 2D cascade theories for subsonic and supersonic flows. The advantages of identifying the aeroelastic modes via a rational fraction modal analysis of the aeroelastic FRFs rather than using a standard complex eigensolution are discussed in some detail. It is found that significant natural frequency and mode shape differences can exist between the structural and aeroelastic systems, a characteristic which must be considered duly when predicting the flutter stability. The consequences of changing the elastic axis position were discussed in the case of a 12-bladed disk and it was found that fitter occurred mainly in torsion for the system studied. Finally, the effects of random and alternate mistuning on flutter stability were also investigated using the same model and it was found that mistuning had a stabilizing effect in some, but not all, cases.