Structural Optimization of Elastic Articulation Rotor System for Dynamic Stability

Multilevel optimization methodology is implied on Elastic Articulation (EA) rotor system to find the global and local configuration to ensure the dynamic stability with Autorotation Index (AI) consideration. EA rotor is the rotor system of generic Georgia Tech Helicopter (GTH) and it is soft-in-plane with 10% effective flapping hinge offset and forward sweep angle. Also, EA rotor has the beneficial features such as flexure beams and torque tube that eliminate dampers and hinges that lead to the its simplicity, structural safety, and reduced weight. To ensure the dynamic stability of such superior system, the methodology utilizes the high-fidelity structural beam analysis tools, DYMORE and VABS that reduce the computation time by allowing a hierarchical decomposition of the problem that separates the local (cross-sectional) sub-problem from the global optimization. The procedure is implemented using MATLAB as the overall optimizer. The results showed that the system achieved optimum values through iteration, however, sensitivity analysis is needed.