Basic Study of Bladed Disk Structural Response.
Abstract
Vibration induced fatigue failure of rotor blades is of continuing concern to the designer of aircraft engines. The emphasis on improved engine performance under the necessary constraints of minimum weight and satisfactory life requires that vibration levels in all rotor blades be kept low. Further, certain important design considerations of rotor blades require a thorough understanding of the aeromechanical characteristics of bladed disk assemblies. These design considerations include (1) blade life prediction which uses vibration amplitudes in its calculations, (2) setting allowable frequency margins which need to be justified on the basis of the intensity of resonant stresses at integral order speeds, and (3) prediction of susceptibility of the component to aeroelastic instabilities. The dynamic response of a shrouded fan was characterized over a range of speeds by subjecting the assembly to forced vibration in vacuum in a spin rig and to distortion induced vibration in an aerodynamic rig. The characterization was established by analysis of blade strain response data obtained when the assembly was driven by predetermined standing or traveling wave forcing through piezoelectric crystal drive elements attached to the blades, by means of an aerodynamic distortion screen and by exit guide vanes. Both tuned and mistuned configurations of the assembly were tested. In addition, the relative motion at shroud interfaces was measured using optical sensors for various input conditions. The vibratory motions were of a microslip type with no evidence of stick-slip type of motion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1983
- Accession Number
- ADA146226
Entities
People
- Akshayaram Srinivasan
- D. G. Cutts
Organizations
- United Technologies Corporation