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Large Deflection Working Group

Lead: Rafael Palacios

Objectives

  • Apply nonlinear aeroelastic simulation codes for the prediction of:
    • Static equilibrium points (static coupling) with large deflections
    • Dynamic stability (flutter) about states of large deflection
  • Investigate nonlinear aeroelastic phenomena induced by large deflections:
    • Variation of structural characteristics (e. g. variation of mode shapes and frequencies)
    • Variation of static and dynamic loads (aerodynamic, inertia)
    • LCO onset (dynamic pressure, AoA), mechanisms, and amplitudes

Background

  • Large elastic deflections are inherent in particular aircraft (HALEs, Sailplanes, modern jet transports) as the result of aerodynamic optimization
    • high aspect ratio to reduce induced drag → high slenderness
  • Bringing more flexibility into jet transport aircraft wings is even a future design goal of aircraft industry
  • Future aeroelastic analysis and design codes must account for aerodynamic (e. g. large rotation of surfaces and forces) and geometric (changes in mass and stiffness) nonlinearities
  • Standard - i.e. linear - analysis and design approaches are not suitable for highly flexible aircraft structures!