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How can I display a curve length in result section
Posted 15 feb 2018, 14:48 GMT-5 Structural & Acoustics, Acoustics & Vibrations, Results & Visualization Version 5.3a 4 Replies
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Hello all.
I'm a new user in comsol and now I have a problem. If you explain me this moment I will be very gratefull for you. I'm trying to calculate a helix edge tension after loading. It's the simplest model. It's a cylinder with interrior helix. After loading helix will be streched. I need to know what his length will be. I've displayed a line graph (total displacement), but It isn't what I need. What I should choose in a gap expression for showing edge length?
Thank you for your attention and help. Vladimir.
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hello Vladimir, i know one way to show the length of this edge. In the line graph settings you first select the helix edge, choose whatever expressions, then change the x-Axis Data parameter to arc length and then plot it. After that you will be able to get the arc length from the graphic x-Axis. Yi
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A more quantitative approach might be to do a line integration along the curve.
-------------------Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
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Hi,
To be more detailed, you can compute the original length of a line by integrating the value '1' on the material frame. The deformed length can be obtained by doing the same integral on the spatial frame.
If you create integration operators under Definitions, then the frame selection is explicit. Integration under Results->Derived Valus relies on the current frame setting in the data set.
Regards,
Henrik
-------------------Henrik Sönnerlind
COMSOL
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Thanks all. I'm sorry for my English writing skills.
Yi Luo, Thank you for your reply. Indeed I have ploted the graph expression/arc-length. But It was the line with length before calculation and expression showed the expressions meaning in each point along the line. For example, If I plot displacemen(arc-length) in line graph window, I will get the extended curve line, but I still need only one meaning for the line - length. If I integrate all line segments of this curve, I will deduce the arc-length aftec calculating. Is's possible, but It's more difficult (I should calculating, export data, import data to matlab...) than getting necessary result in Comsol window. I've believed that It's possible to show the true arc-length in default comcol window.
Edgar J. Kaiser and Henrik Sönnerlind, thank you. It's right way which I've been finding. For showing arc-length I should add the coupling function - integrated fuction. I sould choose the edge or the edges. After meshing I should write in Y-expression gap name of integration fuction of value "1". And after all actions if I plot the line graph It will show only one point value - arc-length.
Thank you for all your reply, It's informative for me,
Kind regards, Vladimir.