ABSTRACT
In the previous chapter, the dynamics of an isolated idealized rotor blade in various uncoupled modes was considered. In this chapter, let us consider the dynamics of coupled motion. The coupled dynamics leads to various aeroelastic instabilities in the rotor blade. The analysis of coupled flap-lagtorsion dynamics of a rotor blade is rather complicated. However, one can bring out the essential characteristics of aeroelastic stability of the blade by considering two separate problems. They are (1) the coupled flap-lag dynamics and (2) the coupled flap-torsion dynamics of an isolated rotor blade. The fundamental understanding of these two simplified cases is a precursor to the complicated study of coupled flag-lag-torsion and axial dynamics of an elastic rotor blade, which is essential for the analysis of rotor blade aeroelastic stability, response, loads, and vibration.
