New Optimization Strategy for Design of Active Twist Rotor

This paper presents the development of a mixed-variable optimization framework for the aeroelastic analysis and design of active twist rotors. Proper tailoring of the blade properties can lead to the maximization of the active twist and the control authority for vibration reductionunder operating conditions. Thus, usingmathematical optimization, the cross-sectional layout is designed using continuous and discrete design variables for an active composite rotor blade to maximize the dynamic active twist while satisfying a series of constraints on blade cross-section parameters, stiffness, and strength. The optimization framework developed includes the Intelligent Cross-Section Generator as the cross-section and mesh generator, University of Michigan/Variational Asymptotic Beam Sectional analysis code for active cross-sectional analysis, and Rotorcraft Comprehensive Analysis Software for aeroelastic analysis of the active twist rotor blade. The optimization problem is solved using a surrogate-based approach in combination with the Efficient Global Optimization algorithm. In this paper, the results with mixed design variables are obtained with three different techniques and are compared with the results obtained using continuous design variables.