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 equations of motion, and of the solution technique, to calculate the sensitivities at a fraction of the cost of an aeroelastic analysis. The mathematical model of the blade includes nonlinearities because of moderately large elastic deflections and the fuselage is described by nonlinear Euler equations, so that the resulting model is valid for both straight and turning flight. The results indicate that the semianalytical technique is very accurate and computationally efficient.