Abstract:Four sets of Mach scale rotors of SA349 helicopter are designed, and four kinds of coupling distribution scheme are obtained by adjusting the ply angle and its distribution of the composite spar of blades. The fullcoupled finite element beam model with 19 DOFs is selected as the str ucture model. The programmed aerodynamic force of the blades is based on SA349 helicopter at flight status 2. The vibratory hub loads of the rotors and blade root vibratory load with differe nt couplings are calculated, and the effectiveness of composite tailored coupling in the helicopter vibration reduction design is validated.