• Registered: 2011-10-11
  • Posts: 8

Topic: format *.thw files

I have calculated the temperature distribution for 480 steps in a 120 min interval across a concrete cross-section exposed to the ISO 834 fire curve from the bottom only.

cross section dimensions: 120x200 mm
mesh: 12x100

Now I want to calculate the fire behavior of a concrete beam with the aforementioned cross section and with a total span of 2m.
The temperature distribution can be assumed uniform across the length of the beam.

How do I import my 2D temperature results into a 3D model?

I have not succeeded in doing this through the GiD preprocessor.

Alternatively I might be able to manually alter the input file for the temperatures (the *.thw file).
But I am not able to read it as a txt file to interpret the contents.

How should I proceed?

Quote Post 1

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

Re: format *.thw files

The easiest way is to run the thermal analysis on a 3D model. A single element is enough for the 3rd direction if the temperature is constant in that direction.

If the temp. field is just a linear gradient, you may also forget thermal analysis at all and just apply it as load in the static model (temperature for volume).

dpryl's Website

Quote Post 2

  • Registered: 2011-10-11
  • Posts: 8

Re: format *.thw files

Thank you,

..."A single element is enough for the 3rd direction"...
You mean that my static model can have a single element in the 3rd direction?
You don't mean that I may build a small segment to run my thermal analysis, after which Atena will automatically extrapolate the results in the third dimension for my large static model?

Example:
Slab sement with dimensions (mm) 6000x300x400.
Uniform temperature during fire assumed in x- and y- directions (6000 and 300).
I need to insert the entire slab segment into the Transport analysis with only a single element in the x- and y- directions?
I cannot do suffice with a transport analysis on a reduced segment of for example 10x300x400, that can later be used for all kinds of slab span lengths? (e.g. 6000; 8000; 10000...)

Explicitly: does Atena extrapolate thermal results, or does Atena need an identical geometrical model (with possibly a different mesh) in the Static and in the Transport analysis?

Quote Post 3

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

Re: format *.thw files

Ad single element: Not the static model, only the thermal model.
The interpolation/etrapolation while importing into statics is based on distance, only having data for a part of the structure would lead to incorrect values in points (far) outside the thermal model.

You can do the thermal analysis for the largest span (10m) and then use the results also for the shorter ones, and only have 1 element in the X direction (6m, 8m, 10m). This of course assumes the temperatures are constant along the X axis, i.e., it is essentially a 2D thermal problem in the Y-Z plane.

dpryl's Website

Quote Post 4