• Registered: 2020-03-06
  • Posts: 35

Topic: Integration Points

Hello,

I would like know, can i determine the number of points of integration for each type of finite elements in ATENA. i found information in the chapter 3. Finite Elements. (Atena_Theory ). E.g. in the text says regardint to truss elements:

"2D and 3D truss elements in ATENA .....These are isoparametric elements integrated by Gauss
integration at 1 or 2 integration points for the case of linear or quadratic interpolation, i.e. for
elements with 2 or 3 element nodes, respectively. They are suitable for plane 2D as well as 3D
analysis problems. Geometry, interpolation functions and integration points of the elements are
given in Fig. ...."

In this case if I'm useing meshing Linear, Do i have only one integration point?
For elements type quadrilateral, how can i determine it?

Thanks
Ingrid

Quote Post 1

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

Re: Integration Points

These settings are available under Mesh tab in GiD.

Quote Post 2

  • Registered: 2020-09-07
  • Posts: 49

Re: Integration Points

Dear Ingrid,
In ATENA the optimal number of integration points is used and for most element types it cannot be controlled by the user. The number of integration points that are used for each element is described in the appropriate section of the Theory manual. If you question is about truss elements. For linear elements 1 ip is sufficient. For quadratic truss elements 2 integration points are used. You are right that for Beam elements you can define the number of integration points along the length, but actually 2 ips are also optimal and default setting there. Is there any special reason why do you think it is important for your analysis?

Regards,
Mohamad

Quote Post 3

  • Registered: 2018-09-04
  • Posts: 18

Re: Integration Points

Taking advantage of Ingrid's question, I've seen some papers where they analyze the behavior of the structural element by varying the number of integration points. For example, a plane element (4 nodes) with 4, 6 or 9 integration points. This affected the load-displacement curve and the reduced integration scheme was recommended because it fitted better with experimental results. Maybe I'm wrong, but in my opinion, unless the numerical results had converged, it doesn't make much sense to use a reduced integration scheme; the higher the integration scheme the better the approximation, right?

Here is my question, is there any particular reason why the integration scheme is not controlled by the user? Does it have to do with the crack band model?

I apologize if my discussion/question is too long but I find this an interesting topic.

Regards,
Marcos

Quote Post 4

  • Registered: 2017-08-30
  • Posts: 6

Re: Integration Points

dear marco

i am by far not an expert in FE but from what i know with displacement-based FE elements they are always too stiff.

here it may get advantageous to use fewer integration points because allthough you lose accuracy in a numerical way the element gets physically less stiff and therefore behaves more natural.

greetings

Quote Post 5

  • Registered: 2020-03-06
  • Posts: 35

Re: Integration Points

Thanks you Dear Pavlo,

My interest about integrations points was for understand better the behavior and the theory that uses Atena with differents finite elements.


Regards!
Ingrid

Quote Post 6