• Registered: 2013-11-07
  • Posts: 6

Topic: Monitoring Points in Nodes

Hi,

I'm monitoring stress along a reinforcement bar and I would like to place the monitoring points in the same coordinates as the nodes. I know it is possible to obtain the nodes coordinates in post-processor->files->print text->reference nodal coordinates, but is it possible to obtain this information in pre-processor?

Thanks in advance.

Quote Post 1

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

Re: Monitoring Points in Nodes

Hello Felipe, in ATENA Engineering 3D, node numbers and coordinates are only available from the Postprocessor. For reinforcement, this has a very good reason: the bars are divided into segments by the ATENA kernel, based on intersections with the surrounding volume elements, and therefore the bar nodes are not known in the preprocessor at all.

However, maybe you do not need to define the monitors, and directly output the values instead - please see ATENA Troubleshooting, 2.1.14 How to get the nodal forces at 100 nodes as output in text-file or other?

Another frequently used option is to define a monitor for the max. or min. value throughout a bar - maybe it can be useful in your case, too.

dpryl's Website

Quote Post 2

  • Registered: 2013-11-07
  • Posts: 6

Re: Monitoring Points in Nodes

Hi,

Thanks for the answer. I'm trying to analyse in detail the evolution of stress along a reinforcement bar, so max and min aren't my top priorities.

I will try to explain what I've done:
Without knowing the nodes coordinates, I've defined Monitoring Points along 25cm of one reinforcement bar. These Monitoring Points are separated 2,5cm from each other. With these Monitoring points I've obtained the following results for one step:
Point in the reinforcement bar (cm) = X
Stress (MPa) = Y
X              Y
0          28,29
2,5       28,29
5          28,29
7,5       84,84
10        84,84
12,5     141,30
15        197,70
17,5     197,70
20        197,70
22,5     260,00
25        260,00
As you can see, I'm obtaining the same result for 0cm as for 2,5cm and 5cm, the same result for 7,5cm as for 10cm, and so on. This kind of behavior happens in all of the analysis steps.
I'm assuming this happens because Atena is giving the results of the nearest Node to each of the Monitoring Points.

So my thought was, If I coud define Monitoring Points in the same coordinates as the Nodes, I wouldn't get repeated values.

What I'm planing to the next is to Run only the first step, go to Post-processor and see what are the coordinates of the reinforcement bar Nodes, return to Pre-processor and define the Monitoring Points, finaly Run all the steps.

Thanks.

Quote Post 3

  • dpryl
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  • Posts: 1,107

Re: Monitoring Points in Nodes

Hello, are you really interested in the whole history in all points along the bar?

If you only need the values along the bar in several steps, it is probably easier to output the values from these steps (and the coordinates) without defining so many monitors.

If you need the whole history along the whole bar, probably the most efficent solution is to
1. store the results for all steps during the analysis (or every 2nd or 5th step if the that is enough detail for your load history interest)
2. export the results from ATENA Engineering 3D into separate step result files (from the Results Manager)
3. create a new project in ATENA Studio based on these result files
4. define the monitor for the whole bar - see ATENA Studio User's Manual, 4.3.2.2 Monitor Request
5. output the monitor values (4.3.2.1 Data Request)

You can also use AtenaWin instead of ATENA Studio (se AtenaWin User's Manual, 8.1.
Supplementing output monitor data after execution of the analysis).

dpryl's Website

Quote Post 4