High-fidelity, 3D stress prediction for composite rotor blades

An accurate knowledge of the complete three-dimensional stress field is a prerequisite to the design of lowmaintenance composite rotor blades. The paper focuses on the development of an efficient methodology for computing three-dimensional stress distributions in helicopter rotor blades. The proposed methodology is based on theoretical developments that allow the determination of exact solutions of three-dimensional elasticity solutions for beams of arbitrary cross-sectional geometry and made of anisotropic composite materials. The effects of curvature, distributed loading, and higher-order strains can also be taken into account. The approach has been implemented in a finite element code, SectionBuilder, which generates two-dimensionalmeshes for cross-sections presenting complex geometries and material distributions and evaluates the sectional stiffness properties and three-dimensional stress distributions in the cross-sections. Because it is based on a parametric definition of the cross-section, SectionBuilder facilitates the modeling and analysis process of composite rotor blades and it can be used as a pre- and post-processor of comprehensive analysis codes.