Cross-sectional design of composite rotor blades

An important step of rotor blade design is to design cross sections that possess specified stiffness and inertia properties. This paper describes an innovative methodology for design of composite rotor blade cross sections. The proposed methodology includes four parts: an improved optimization model, a parametric geometry generator with appropriate mesh, an efficient and reliable cross-sectional analysis program, and an efficient optimizer. The optimization model is improved by adding manufacturability constraints that are generally ignored in traditional design approaches. The optimization model also integrates mass and stiffness properties along with structural integrity. To solve the optimization problem with a mix of continuous and discrete variables resulting from manufacturability constraints, a hybrid optimization method is developed that can rapidly search for and find an optimum design. The design methodology is demonstrated by several examples. In addition, a sensitivity analysis is conducted by which design variables with little effect can be eliminated. Based on this approach, two models with a reduced number of design variables are created and the resulting simplified designs are evaluated.