Mathematical models based on the finite element method of structural analysis, as embodied in the NASTRAN computer code, are routinely used by the helicopter industry to calculate airframe static internal loads used for sizing structural members. Historically, less reliance has been placed on the vibration predictions based on these models. Beginning in the ealry 1980's NASA's Langley Research center initiated an industry wide program with the objective of engendering the needed trust in vibration predictions using these models and establishing a body of modeling guides which would enable confident future prediction of airframe vibration as part of the regular design process. Emphasis in this paper is placed on the successful modeling of the Army/Boeing CH-47D which showed reasonable correlation with test data. A principal finding indicates that improved dynamic analysis requires greater attention to detail and perhaps a finer mesh, especially the mass distribution, than the usual stress model. Post program modeling efforts show improved correlation placing key modal frequencies in the b/rev range within 4 % of the test frequencies.


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    Title :

    The NASA/industry design analysis methods for vibrations (DAMVIBS) program-Boeing helicopters airframe finite element modeling


    Additional title:

    Die analytischen Konstruktionsmethoden von NASA und Industrie zur Schwingungsermittlung (DAMVIBS) - Modellierung des Hubschrauberkörpers bei Boeing mit finiten Elementen


    Contributors:
    Gabel, R. (author) / Long, P. (author) / Reed, D. (author)


    Publication date :

    1992


    Size :

    12 Seiten, 14 Bilder, 3 Tabellen, 6 Quellen


    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English