A multidisciplinary optimization approach for vibration reduction in helicopter rotor blades

The paper addresses the integration of blade dynamics, aerodynamics, structures and aeroelasticity in the design of helicopter rotors using a formal optimization technique. The interaction of the disciplines is studied inside a closed-loop optimization process. The goal is to reduce vibratory shear forces at the blade root with constraints imposed on dynamic, structural and aeroelastic design requirements. Both structural and aerodynamic design variables are used. Multiobjective formulation. procedures are needed since more than one design objective is used. A nonlinear programming technique and an approximate analysis procedure are used for optimization. Substantial reductions are obtained in the vibratory root forces and moments while satisfying the remaining design criteria. The results of the optimization procedure using two multiobjective formulation procedures, are compared with a baseline or reference design.