The aeromechanical stability of a helicopter with an elastically coupled composite bearingless rotor in forward flight is investigated. A finite element based structural analysis including the effects of transverse shear, torsion related out-of-plane warping, and warping restraint is incorporated into the University of Maryland Advanced Rotorcraft Code (UMARC). The out-of-plane warping model is developed using a fourth order polynomial over the cross section area. The effects of restrained warping are incorporated by modifying the torsional stiffness distribution along the blade. Three soft in-plane bearingless rotor configurations, including bending-torsion structural couplings are analyzed. The analysis covered free flight propulsive trim, blade steady periodic response, and stability of the perturbed rotor-body system. Elastic pitch-lag couplings caused by the ply layup of the flexbeam have a significant effect on the vibratory response, hub loads, and aeroelastic stability of a bearingless rotor. Negative pitch-lag elastic couplings have a stabilizing effect on the regressive lag mode in hover and forward flight. The stability margin is increased by as much as 250 percent.


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    Titel :

    Aeroelastic analysis of a composite bearingless rotor in forward flight using an improved warping model


    Weitere Titelangaben:

    Die aeroelastische Analyse eines lagerlosen Verbundrotors beim Vorwärtsflug unter Anwendung eines verbesserten Verwölbungsmodelles


    Beteiligte:
    Tracy, A.L. (Autor:in) / Chopra, I. (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    1995


    Format / Umfang :

    12 Seiten, 15 Bilder, 4 Tabellen, 30 Quellen




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch





    Aeroelastic Analysis of a Composite Bearingless Rotor in Forward Flight with Improved Warping Modeling

    Tracy, A. L. / Chopra, I. / Ames Research Center et al. | British Library Conference Proceedings | 1993


    Aeroelastic Analysis of a Composite Bearingless Rotor in Forward Flight with Improved Warping Modeling

    Tracy, A. L. / Chopra, I. / Ames Research Center et al. | British Library Conference Proceedings | 1994


    Aeroelastic stability of bearingless rotors in forward flight

    Dull, Andrew L. / Chopra, Inderjit | NTRS | 1987