Aeroelastic response and hub load of composite hingeless rotor in forward flight with elastic couplings

The aeroelastic response and hub load of a composite hingeless rotor in forward flight with elastic couplings are investigated. The structural model in this analysis includes the effects of transverse shear deformation, out-of-plane warping and aeroelastic coupling. The aerodynamic loads acting on the blade are obtained using quasi-steady aerodynamic theory. Dress model is for the rotor inflow distribution. A 21-DOF beam finite element, including transverse shear DOF and warping DOF, is developed for analysis. The governing differential equations of motion for hingeless rotor can be derived using the Hamilton's principle. The effects on the aeroelastic response and hub load of a composite hingeless rotor in forward flight with elastic couplings are presented. Results show that the torsion response is substantially altered by the elastic couplings. Vibratory hub loads are changed as a result of the elastic couplings. Negative lag bending-torsion and positive extension-torsion couplings reduce the vertical hub shear forces by approximately 5%.