1. Meryem Nisa Ataç

       Dear Dr. Yu,
       I have a question related to VABS and GEBT. I have a case like below:
       There is a blade model with a bending load which is applied at the Shear Center (SC). I am confused about in which point I have to get the stiffness matrix terms to be able to obtain correct displacement and stress results
    from GEBT and VABS.
    a) Do I have to perform VABS analysis according to SC, then I have the stiffness terms at SC and put the found flexibility matrix to GEBT or
    b) Do I have to perform VABS analysis according to both Neutral Axis (NA) and Shear Center (SC); and then, for axial, shear and bending stiffnesses use the NA flexibility and for torsional stiffness use the SC
    flexibility terms?
    c) If the answer is b, how about coupling terms?
       I would appreciate it if you could help me handling this problem as soon as possible.
    Kind regards,
    M. Nisa ATAÇ

  2. Wenbin Yu

    In your VABS run, you can put the origin of coordinate anywhere you think convenient. Then, VABS will give you a Timoshenko stiffness model for that origin and corresponding shear center with respect to that point. The reference point you choose becomes your reference line in your GEBT run. In other words, you need to provide a forces and moments to be equivalent to the force you applied at the shear center.

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