AEROELASTIC OPTIMIZATION OF A HELICOPTER ROTOR WITH SINGLE-CELL COMPOSITE BLADES FOR VIBRATION REDUCTION

An unsteady aerodynamic environment and highly flexible rotating blades lead to harmonic loadings on the rotor so as to cause high vibration in the helicopter.An optimization is carried out for a four-bladed,soft in-plane hingeless rotor consisting of a single-cell composite box-beam spar for helicopter vibration reduction.The design variables are the ply angles of the box-beam walls;the objective function is of the vibration hub loads.Constraints are imposed on blade rotating frequencies and aeroelastic stability.As compared to the initial design,the optimum solution results in a 20-70% reduction of the 4/rev hub loads.