• Registered: 2019-05-24
  • Posts: 2

Topic: application of load and constrains

Dear Cervenka Consulting,

I'm a beginner Atena Science user. I have chosen this software for FEM modeling of reinforced concrete beam-column joint which is going to be a part of my dissertation thesis. The model was built in the GID 12.0.2 and a static analysis was run in Atena Studio 3d v.5.

The result of the analysis is reflecting that the model is not working properly. The problem is that tension appears instead of compression in the beam region where load was applied as well the top of the column. Therefore, I would like to ask some help in solving this case. Please find below more information about the model and the applied settings.

First of all, this study focuses on the shear reinforcement behavior in the column and the damage of beam-column joint. I would like to simulate the behavior of a beam-column joint under cyclic load. The top and the bottom of the column is going to be hinged supported in order to allow free rotation.
Beam-column joint geometry:
-cross-section of column and beams: 30x30 cm, column length: 2.10 m, beams length: 80 cm
- materials properties based on the Atena’s recommendations: concrete C20/25 – ConcreteEC2, reinforcement – S500, 1DReinforced  and plates- solid elastic
Conditions:
- constrains for points and lines on the plates
- “fixed contact for surface” (master-slave connection used between the column – beams, column plates, beams- plates) – in each of the intervals.
- monitors for point placed in the 1st interval in order to detect the displacements and the reactions
- intervals: 1st - Self-weight, 2nd – monotonic axial load on the top plate of column in order to simulate the compression, 3rd - Cyclic load – it was applied a point load on the bottom plate of the left beam and another point load on the top plate of the right beam, 4th - Cyclic load – (inverse loading of the 3rd interval) it was applied a point load on the bottom plate of the left beam and another point load on the top plate of the right beam.

Thank you for your attention.

Best regards,
Mirnadettami_005

Quote Post 1

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

Re: application of load and constrains

Hi Mirnadettami_005,
Can you share you model at any file share service?

Quote Post 2

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

Re: application of load and constrains

Dear Mirnadettami_005,
is there any reason why you prefer applying the load in multiple points, making the monitoring more work (I understand you need 2 points as you load both beam ends, but why 4 - different loading point for each direction)?
The simplest would be to connect the 2 loading plates (like they probably are in the experiment) and apply the load in both directions to a single point.

With alternating the 2 plates, you have to decide when to switch, and the extreme position is rarely the optimal point... and even unloading back to 0 position (with Coeff. -1), then applying the other load does not always work very well (as 0 position and 0 force tend to shift from each other more or less).

If/when you have further problems/questions, you can follow Troubleshooting, 2.1.1 to send us your model etc.

Regards.

dpryl's Website

Quote Post 3

4 Reply by mirnadettami_005 (edited by mirnadettami_005 2019-05-28 08:25:17)

  • Registered: 2019-05-24
  • Posts: 2

Re: application of load and constrains

Dear dpryl,

First of all, thank you for your interest.

I understand your point of view, the 4th interval was realized to prevent appearing of tension in the beam region where load was applied. It means, I have tried your proposed solution before (2 loads applied on the beams), but unfortunately between the beam and the plate had tension instead of compression…. finally, I applied the extra loads and interval as I mentioned in my last comment.


Best regards,
mirnadettami_005

Quote Post 4