APPLICATION OF DESIGN OPTIMIZATION TECHNIQUES TO ROTOR DYNAMICS PROBLEMS

Optimization techniques have been applied to various rotor dynamics problems to gain insight into the design process, project potential design benefits, and evaluate alternative problem formulations and solution strategies. A constrained optimization program was linked to a coupled-mode eigenvalue analysis to achieve a closed-loop computer program for optimizing blade dynamic characteristics. Analytical studies have been performed on a series of problems related to maximizing bearingless rotor inplane structural damping, placing blade natural frequencies, minimizing hub vibratory shears, and minimizing rotor modal vibration indices. These examples are representative of a hierarchy of optimization problems from relatively simple to complex, involving nonlinearities, multiple design criteria, multicomponent objective functions, and large numbers of design variables. The relative merits of alternative optimization algorithms and problem formulations are compared. Strategies to improve the efficiency and reliability of problem solution are discussed.