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Influence of mistuning on blade torsional flutter
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Srinivasan, A. V. |
| Copyright Year | 1980 |
| Description | An analytical technique for the prediction of fan blade flutter was evaluated by utilizing first stage fan flutter data from tests on an advanced high performance engine. The formulation includes both aerodynamic and mechanical coupling among all the blades of the assembly. Mistuning is accounted for in the analysis so that individual blade inertias, frequencies, or damping can be considered. Airfoil stability was predicted by calculating a flutter determinant, the eigenvalues of which indicate the extent of susceptibility to flutter. When blade to blade differences in frequencies are considered, a stable system is predicted for the test points examined. For a tuned system, it was found that torsional flutter can be predicted at a limited number of interblade phase angles. Examination of these phase angles indicated that they were "close" to the condition of acoustic resonance. For the range of Mach numbers and reduced frequencies considered, the so called subcritical flutter cannot be predicted. The essential influence of mechanical coupling among the blades is to change the frequencies of the system with little or no change in damping; however, aerodynamic coupling together with mechanical coupling could change not only frequencies, but also damping in the system, with a trend toward instability. |
| File Size | 12515874 |
| Page Count | 56 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19800022846 |
| Archival Resource Key | ark:/13960/t3809wz2s |
| Language | English |
| Publisher Date | 1980-08-01 |
| Access Restriction | Open |
| Subject Keyword | Aerodynamics Couplings Shrouds Rotor Aerodynamics Turbofan Engines Flutter Analysis Torsional Vibration Equations of Motion Aeroelasticity Prediction Analysis Techniques Tuning Fan Blades Computer Programs Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
