Optimal Design Application On The Advanced Aeroelastic Rotor Blade

The vibration and performance cptimization procedure using regressicn analysis has been successfully applied to an advanced aernelastic blade design study. The major advantage of this regression technique is that multiple optimizations can be performed to evaluate the effects of various objective functions and constraint functions. In this application, the data bases obtained from the rotorcraft flight simulation program C81 and Myklestad mode shape program are analytically determined as a function of each design variable. Those predicted results from regression equations, such as performance, vibration, and nodal parameters, when compared with C81 and Myklestad outputs, correlate exceptionally well. The regression equations also predicted the minimum of 4/rev total vertical hub shear based on the coefficients of each equation. This approach has been verified for various blade radial ballast weight locations and blade planforms. This method can also be utilized to ascertain the effect of a particular cost function which is composed of several objective functions with differert weighting actors for various mission requirements without any additional effort. Utilization of this technique can significantly reduce the engineering efforts and computer time to optimally design a high performance and low vibration blade.