EFFICIENT SENSITIVITY ANALYSIS FOR ROTARY-WING AEROMECHANICAL PROBLEMS

This paper describes a method for the calculation of the sensitivities of rotating blade root loads and hub loads to changes of blade design parameters using a chain rule differentiation approach. The algorithm exploits features of the formulation of the blade and fuselage equati ons of motion, and of the solution technique, to calculate the sensiti vities at a fraction of the cost of an aeroelastic analysis. The mathe matical model of the blade includes nonlinearities because of moderate ly large elastic deflections and the fuselage is described by nonlinea r Euler equations, so that the resulting model is valid for both strai ght and turning flight. The results indicate that the semianalytical t echnique is very accurate and computationally efficient.