Aeroelastic Modeling of Blade Vibration and its Effect on the Trim and Optimal Performance of Helicopter Rotors using a Harmonic Balance Approach
This dissertation concerns the optimization of the aeroelastic performance of conventional
helicopter rotors, considering various design variables such cyclic and higher
harmonic controls. A nite element model is introduced to model the structural
eects of the blade, and a coupled induced velocity/projected force model is used
to couple this structural model to the aerodynamic model constructed in previous
works. The system is then optimized using two separate objective functions: minimum
power and minimum vibrational loading at the hub. The model is validated
against several theoretical and experimental models, and good agreement is demonstrated
in each case. Results of the rotor in forward
ight demonstrate for realistic
advance ratios the original lifting surface model is sucient for modeling normalized
induced power. Through use of the dynamics model the vibrational loading minimization
is shown to be extremely signicant, especially when using more higher
harmonic control. However, this decrease comes at an extreme cost to performance
in the form of the normalized induced power nearly doubling. More realistic scenarios
can be created using multi-objective optimization, where it is shown that vibrational
loading can be decreased around 60% for a 5% increase in power.
Mechanical engineering
Aeroelastic
Harmonic Balance
Helicopter
Optimization
Performance
Vibration

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