Multiple-Surrogate Approach to Helicopter Rotor Blade Vibration Reduction

The advantages of using multiple surrogates for approximation and reduction of helicopter vibration are studied. Multiple approximation methods, including a weighted-average approach, are considered so that pitfalls associated with only using a single best surrogate for. the rotor blade vibration-reduction problem are avoided. A vibration objective function corresponding to a flight condition in which blade-vortex interaction causes high levels of vibration is considered. The design variables consist of cross-sectional dimensions of the structural member of the blade and nonstructural masses. The optimized designs are compared with a baseline design resembling a Messerschmitt-Bolkow-Blohm BO-105 blade. The results indicate that at relatively little additional cost compared with optimizing a single surrogate, multiple surrogates can be used to locate various reduced-vibration designs that would be overlooked if only a single approximation method was employed, and the most accurate surrogate may not lead to the best design.