A NEW SENSITIVITY ANALYSIS FOR STRUCTURAL OPTIMIZATION OF COMPOSITE ROTOR BLADES

This paper presents the mathematical details of the formulation for th e sensitivity derivatives for the structural dynamic, aeroelastic stab ility, and response characteristics of a rotor blade in hover and forw ard flight. The formulation is denoted by the term semi-analytical app roach, because certain derivatives are evaluated by a finite differenc e scheme. Using this formulation, sensitivity derivatives for structur al dynamic and aeroelastic stability characteristics were evaluated fo r a composite rotor blade. Useful conclusions regarding the relative m erits of the semi-analytical approach, when compared to a pure finite difference approach, are obtained. In addition, influence of ply orien tation angles on the vibratory hub loads in forward flight is also con sidered.