Aeroelastic Simulation of Complex VTOL Configurations

Answer Engineering has implemented a combination of mid-fidelity aerodynamic and structural tools to simulate the aeroelastic behavior of VTOL transition from hover to forward flight. The transition maneuver is a complex aerodynamic environment that has become a common challenge in recent VTOL designs. Proven methods for aeroelastic analysis exist for fixed surfaces, rotors, prop whirl, control surface buzz, and other singular circumstances, but combinations of these phenomena require new methods. Solutions simultaneously coupling aerodynamics and elasticity of rotors, motor mounts, booms and wings in a multi-physics simulation allows for insight to the aeroelastic stability and aero-structural interaction of the vehicle. Both time and frequency domain outputs are created to study spectral content and general stability of aeroelastic systems. Stiffness requirements for large VTOL aircraft have been shown to dominate structural sizing of many VTOL components when compared to typical static, modal, and vibration load analysis on the same elements. Bend-twist couplings of rotor and vehicle structures can be modeled and optimized through composite ply angle changes to reduce aeroelastic loads and stabilize structures in previously problematic conditions. The aeroelastic simulation is implemented on cloud resources to simultaneously compute a large array of flight states varying edgewise flow velocity, motor torque, RPM, aircraft angle of attack, and sideslip. This solution sequence previously might take a single engineer months to iterate through and can now be simulated and reported within a day. This scalable aeroelastic simulation approach allows prediction and remediation of aeroelastic failure throughout the transition envelope before designs are committed into expensive test aircraft.