• Registered: 2021-01-13
  • Posts: 5

Topic: Moment integration of 3D element

I am wondering if there is a function of ATENA to automatically integrate the moment of a selected plane/cut/cross-section

of a beam/column model for verification purpose.  The element type of the beam/column is 3D hexahedron or tetrahedron,

brick or shell element.  I know that the data request in Atena Science could output the M n q shell of the selected nodes,

but it needs manual integral to get the moment or shear force of the entire cross-section and this process could be

extremely strenuous for complicated cross-sectional shape (get worse for more elements and lack of accuracy).


An alternative I know is to calculate the moment from the node reactions (extracted from ATENA), and solve for the moment

diagram of the beam indirectly by hand if the loading is known.  But other than this, any better strategies?

Quote Post 1

  • From: Finland
  • Registered: 2019-03-28
  • Posts: 138

Re: Moment integration of 3D element

Yes, there is a special tool and it is very good! You have to check paragraph 4.2.1 Cuts – Forces and moments from the User manual "ATENA-Science-Studio_Users_manual.pdf". However, you haven't specified whether you use ATENA 3D or ATENA Science. My reference is valid for ATENA Science.

Quote Post 2

  • Registered: 2021-01-13
  • Posts: 5

Re: Moment integration of 3D element

Dear Pavlo,

Thanks for the reply. It's ATENA Science. I checked the toolbox (Forces and moment) you mentioned in the cuts section, it works.  However, the result it yields look weird compared the other methods I used, see below for My' (Moment about the centroid y-y):

(1) Manual integral from the node results (sectional M n q) of the cut section = 4041(kip*ft);
(2) Slope deflection method calculated by hand (idealized structural analysis) = 4695 (kip*ft);
(3) Moment calculated from the reaction results provided by ATENA = 4699 (kip*ft);

(4) Result from the toolbox (Forces and moment) = 1.79E+10 (kip*ft), the original number in ATENA given = 2.43E+07 (MN*M).
All the other colored results look normal to me, e.g. stress or M n q results.

This automatically integrated result for cut section is insanely high. But the moment shape of the entire span looks good to me.

Is there a unit setting bug for this toolbox?

Thank you!
Clay

Quote Post 3

  • From: Finland
  • Registered: 2019-03-28
  • Posts: 138

Re: Moment integration of 3D element

Hi Clay,

I have never used any units except SI. Hence, I have no idea whether your problem could be related to units settings. I have used this tool many times and it worked fine.
One more thing to be mentioned is that integration is performed for the visible elements only (e.g., in case rebars are hidden their forces are not considered and moment is less than shall be).

Quote Post 4