DECOMPOSITION-BASED OPTIMIZATION PROCEDURE FOR HIGH-SPEED PROP-ROTORSUSING COMPOSITE TAILORING

A multilevel optimization procedure is developed to investigate the ef fect of changes in blade planform and composite tailoring on blade aer odynamic and structural performance of prop-rotor aircraft. Both high- speed cruise and hover performance are considered simultaneously. A co mposite box beam model is used to represent the principal load carryin g member in the rotor blade. The upper level objective is to simultane ously maximize the high-speed cruise propulsive efficiency and the hov er figure of merit using planform design variables. Constraints are im posed on other aerodynamic performance requirements and also on the ph ysical dimensions of the blade. The lower-level objective is to reduce the critical tip displacements in both hover and cruise using composi te tailoring. Optimization is performed using a nonlinear programming approach in the upper level and integer programming technique in the l ower level. Optimum designs are compared with the XV-15 rotor blade pe rformance at 300 kn, which is used as a baseline or reference design, and also with the results obtained from a purely aerodynamic optimizat ion procedure. The results show significant improvements in both the a erodynamic and structural performance.