• Registered: 2012-10-07
  • Posts: 4

Topic: change the GAP in different stages ?

I am now modeling the T section prestressed cocrete beam. The interface of the top flange and the web is simulated by 3D interface element.

However, I want to change the material properties of interface element (GAP) in different construction stages. Can this be realized in ATENA? 

Thank you very much, I greatly appreciate your assistance.

Quote Post 1

  • dpryl
  • CC software developer
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  • Registered: 2007-07-13
  • Posts: 1,107

Re: change the GAP in different stages ?

Dear tengtongseu, I am afraid there is no direct and easy way to define construction process for interfaces or a time-dependent (or step-dependent) Interface Material using the ATENA Engineering (2D or 3D) nor ATENA Science GUEs.

To be able to give you modelling advice, we need to know more about what you are modelling and why you wish to change the Interface Material properties. For example, if you add a macroelement in ATENA 3D, the interface connecting it to the already existing structural memebers is created with the ME being added (and deleted with MEs being deleted), and therefore there is normally no need to change the Interface settings.

dpryl's Website

Quote Post 2

  • Registered: 2012-10-07
  • Posts: 4

Re: change the GAP in different stages ?

I want to model the T-sectional concrete beam. Whose web is cast and applied pre-tensioned prestressing, after that, the top flange is cast.
At the beginning, I deactivate the top flange. However, there is a obvious  penetrate at the interface of top flange and web! The results can not be accepted.
So I guess, if I can set the interface element in different stages. At the begining, the GAP has no tangential stiffness, after the web is cast and the prestressing is applied, I restore the tangential stiffness?

Quote Post 3

  • dpryl
  • CC software developer
  • Offline
  • Registered: 2007-07-13
  • Posts: 1,107

Re: change the GAP in different stages ?

Dear tengtongseu, without seeing your model (not even knowing if you are creating it in ATENA Science / GiD or ATENA Engineering 3D) and a sketch of what you are modelling, it is hard to guess what can be the problem...

For modelling construction process, please understand the following:
1. the newly added elements have to be SLAVE in the connection
2. the connected nodes are shifted according to the current position of the already existing part of the structure. Please note only the nodes in contact are being shifted, i.e., if the flange is wider that the web, only the nodes above the web are shifted and the rest are placed at the unshifted positions.
3. as long as only one of the macroelements/volumes connected by a an interface exist, the interface settings do not have any influence as no elements exist for the interface
4. numerically modelled contacts have finite stiffness. If the deformations are scaled up largely, it is normal to see some overlaps.

dpryl's Website

Quote Post 4