Certification by Analysis Uncertainty Quantification

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  • 1.  Nastran structural model in SI units

    Posted 11 days ago

    Hello everyone,

     

    I have been using the NASTRAN structural model in SI unit shared on https://www.aiaa-uq4cba.org/. I noticed that both models (SI and imperial) units have the same values for the lugs stiffnesses as visible in the screenshots below.

    Based on the results I am getting, I suspect that the values in SI units are not the correct one.

     

     I would appreciate if you could look into this and come back with a comment.

    Thank you in advance.

    Kind regards,



    ------------------------------
    Arianna Bosco
    Dr
    Siemens Industry Software
    Munich
    ------------------------------


  • 2.  RE: Nastran structural model in SI units

    Posted 11 days ago

    The lug stiffnesses are set to "infinitely" large values to represent a rigid connection at the fuselage; a value of 10^9 is large enough for both the SI and the Imperial unit model, and therefore was not converted.  Note that if realistic stiffnesses were used for the attachments, then there would be different numbers between the two models.

    Tom



    ------------------------------
    Thomas Wittenberg
    Engineer
    Boeing Commercial Airplanes
    Seattle WA
    (425)387-7978
    ------------------------------



  • 3.  RE: Nastran structural model in SI units

    Posted 10 days ago

    Thank you, Thomas for the answer.



    ------------------------------
    Arianna Bosco
    Dr
    Siemens Industry Software
    Munich
    ------------------------------

    Original Message


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