Transverse Shear Stiffness

1) Do you know why the transverse shear stiffness for beams (TXZ & TXY) in Mechanical has units of N/m in spite of being defined as follows in the manual (for shells the definition is different):


   (TXZ and TXY default to A*GXZ and A*GXY, respectively, where A = cross-sectional area) 

2) In order to change the transverse shear coefficient of an imported beam model, we have to use SECCONTROL in Mechanical Workbench. Do you know how to specify the scope of the command, that is to say the particular beams in the model to which this applies? Do we have to precede the command with other specifications (like post-processing or whatever). I am not that familiar with APDL commands (just started using it for FSI with fluent).

Any clarification/suggestion on the above will be much appreciated.



  • TamTokTamTok Member
    edited May 2020

    I am posting the answer because it might help someone:

    1) The units should be N, but Mechanical shows it in N/m just because it conventionally considers it as the ratio of applied shear force to transverse displacement for a beam of unit length (1 m is the denominator).

    2) Transverse shear coefficients can be imposed in Mechanical Workbench as follows:

       2.1) The relevant line geometry has to be selected, then you have to right-click and insert "Commands";

       2.2) All the beam cross-section properties need redefining:

                SECTYPE,n,BEAM,ASEC ! n is the section ID number 



    A final remark on 2.2: The beam cross-section properties are defined twice in workbench, and they should be deleted from the cross-section card, otherwise Workbench cannot assign the physical properties to the beam, which are not defined from the cross-section properties input as command lines but from the cross-section card.


  • What are these: A,Iyy,Iyz,Izz,Iw,J,CGy,CGz,SHy,SHz,TKz,TKy,TSxz,TSxy? @TamTok

  • Hi @senagultunca ,

    In this case, TamTok is defining an arbitrary section (ASEC option in SECTYPE command), so the cross-sectional properties must be supplied. These are designated as "A, Iyy, etc." and can be found in the Help manual for the SECDATA command in the Mechanical APDL documentation. (A=cross section area, Iyy=moment of inertia about element y-axis, etc.)



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