Aeroelastic characteristics of a rotating blade axially loaded by an internally guided tendon

Abstract

Active tendon concept with internal guides is put forward to avoid the significant resonant vibration of rotor blades with variable speed. However, the influence of the aerodynamic effects has not been taken into account in the previous studies. In this paper, a rotating pretwisted flap-lag-torsion coupled blade axially loaded by a guided tendon is developed, and the aerodynamic loads are incorporated into this framework using a classical combination of Greenberg's and Theodorsen's theories. The equilibrium deflection of the blade-tendon model is calculated first, and the stability analysis is carried out around the equilibrium deflection using the linearized model. It is found the first torsional mode of the blade becomes unstable with the increasing rotational speed, and the axial force only has a slight influence on the critical speed. The guided rigid attachments only have a slight influence on the critical speed and unstable frequency. Therefore, the application of active tendon concept will not have a substantial influence on the dynamic stability of the blade.