Inquiries about GEBT connection point boundary conditions

  1. Byeonguk Im



    I am studying the connection point of the GEBT which is explained in the journal "GEBT A general-purpose ..." by W. Yu. 

    Is there any missing point in my understanding? Please help. 


    According to the paper, if one wants to add a revolute joint with a prescribed rotation at a connection point, 


    18N+12+3(moment at the connection) degrees of freedom will be the unknown vector. 


    For example, if the connection point is in between element i and j; 

     ( element i ) - ( C ) - ( element j )


    Then, the equilibrium equation for the adjacent element will be

    (f_psi_i+)  + (f_psi_j-)    - M_C_hat = 0 

       -> (f_psi_i+)    - M_C_hat = 0   because element j will freely rotate ?


    corresponding compatibility equation is:

    (f_M_i+) + theta_C_hat = 0,   (f_M_j-) - theta_C_hat = 0, 

      -> (f_M_i+) + theta_C_hat = 0

    where the second equation would vanish. 



    Best regards,


    Byeonguk Im.