Accession Number : ADA300977

Title :   Aeroelastic Analysis of Transient Blade Dynamics During Shipboard Engage/Disengage Operations.

Descriptive Note : Professional paper,

Corporate Author : NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD

Personal Author(s) : Geyer, William P., Jr. ; Smith, Edward C.

PDF Url : ADA300977

Report Date : 21 AUG 1995

Pagination or Media Count : 25

Abstract : An analysis tool has been developed to predict transient aeroelastic rotor response during shipboard engage/disengage sequences. The blade is modeled as an elastic beam undergoing deflections in flap bending and torsion. The blade equation of motion is formulated using Hamilton's principle and spatially discretized using the finite element method. The discretized blade equations of motion are integrated for a specified rotor speed run-up or run-down profile. Blade element theory is used to calculate quasi-steady or unsteady aerodynamic loads in linear and nonlinear regimes. Three different simple wind gust distributions are modeled. Basic ship roll motion characteristics are also included in the shipboard airwake environment. An H-46 rotor system model is developed and shows excellent correlation with experimental static tip deflection and blade natural frequency data. Parametric studies are conducted to systematically investigate the effects of collective and cyclic control settings, droop stop angle, and ship motion on blade response. These studies indicate that collective and cyclic control inputs have a moderate effect on maximum negative tip deflections. Torsion and unsteady aerodynamics are shown to be very important to the blade response at high wind speeds for spatially varying gusts. (MM)

Descriptors :   *SHIP MOTION, *HELICOPTER ROTORS, *AEROELASTICITY, EQUATIONS OF MOTION, WIND, ELASTIC PROPERTIES, BENDING, AERODYNAMIC LOADING, AERODYNAMIC CHARACTERISTICS, GUSTS, SHIPBOARD, WIND VELOCITY, FLAPS(CONTROL SURFACES), UNSTEADY FLOW, HAMILTONIAN FUNCTIONS.

Subject Categories : Aerodynamics
      Helicopters
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE