Multi-objective Optimization of Rotorcraft Blade Structure with Manufacturing Considerations and Preliminary Validation

Abstract:
This work extends an integrated VABS (iVABS) framework for rotor blade structural optimization by incorporating enhanced cross-sectional parameterization and manufacturing-aware design considerations. The refined model includes features such as curved spar corners, continuous wrap-around skins, conformal non-structural mass, and ply-level discretization, enabling a more realistic representation of composite blade structures within a scalable optimization framework. Multi-objective blade-level optimization studies are conducted on a UH-60A-based blade using three representative cross-sections, considering both unconstrained and strength-constrained design cases. For the unconstrained problem, the optimal design achieves close agreement with target stiffness properties while also providing improved matching of mass center and shear center locations compared to prior design. When a minimum strength ratio is enforced, the feasible design space is significantly reduced, resulting in increased deviation from the target stiffness properties. However, strength-constrained designs exhibit improved agreement in mass per unit length, indicating a positive correlation between strength requirements and mass matching. The resulting structural trends are physically consistent, with thicker spars near the blade root and thinner, more elongated spars toward the tip. To connect computational design with physical realization, a manufacture–test campaign is conducted using a representative spar section. A composite spar based on an iVABS-derived layup is fabricated using aerospace-grade prepreg materials and standard tooling procedures. Experimental measurements show good agreement with iVABS predictions, including approximately 5.3\% error in mass per unit length and 1 2\% error in center-of-gravity location. These results provide preliminary validation of the framework and demonstrate its capability to generate manufacturable designs with consistent structural predictions.

Did you attend Forum 82? Click the preview below to access the full paper.