Polymeric composites are used to manufacture hingeless, bearingless composite rotor hubs for helicopters. These components are made of fewer parts and offer the advantages of reduced weight and drag, compared to metal hubs. During flight, these rotor hubs experience constant axial tension load from the centrifugal forces, and transverse bending in the flapping flexure region. In order to accommodate bending loads, composite flexbeams use internal ply-drops to create a nonlinear taper. In this study, nonlinear-tapered flexbeam specimens from a full-size composite helicopter rotor hub flexbeam were tested under combined constant axial tension and cyclic bending loads. Two different graphite/glass hybrid configurations tested under cyclic loading failed by delamination in the tapered region. A 2-D finite element model was developed which closely approximated the flexbeam geometry, boundary conditions, and loading. The analysis results from two geometrically nonlinear finite element codes, ANSYS and ABAQUS, are presented and compared. Strain energy release rates (G) associated with simulated delamination growth in the flexbeams are presented from both codes. These results compare well with each other and suggest that the initial delamination growth from the tip of the ply-drop toward the thick region of the flexbeam is strongly mode II. The peak calculated G values were used with material characterization data to calculate fatigue life curves for comparison with test data. A curve relating maximum surface strain to number of loading cycles at delamination onset compared well with the test results.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Fatigue life methodology for tapered hybrid composite flexbeams


    Contributors:

    Published in:

    Publication date :

    2006


    Size :

    10 Seiten




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English




    Structural Integrity of Composite Flexbeams

    Vizzini, A. J. / Lee, S. W. / American Helicopter Society | British Library Conference Proceedings | 1993



    Vibration absorbing device for flexbeams

    MANCHER JOSHUA / KRISTIE LEWIS L / CAPPELLI MARCUS D | European Patent Office | 2020

    Free access

    Vibration absorbing device for flexbeams

    MANCHER JOSHUA / KRISTIE LEWIS L / CAPPELLI MARCUS D | European Patent Office | 2015

    Free access