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Finding the angle of a deformed surface?
Posted 20 mars 2013, 07:20 UTC−4 Results & Visualization, Structural Mechanics Version 4.3a 1 Reply
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Hi all,
I'm running a solid mechanics simulation where the two ends of a cylinder will get deformed/bent by a small amount.
When visualizing the results, how would I extract the angle of the surface?
My idea would be:
- derived values / surface integration over: nx
- derived values / surface integration over: ny
- derived values / surface integration over: nz
then normalize by the area of the surface, and calculate the direction of the average surface normal.
what's the most straightforward way to implement this?
thanks,
Anders
1 Reply Last Post 20 mars 2013, 08:25 UTC−4
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Posted:
1 decade ago
Hi
the angles w.r.t. the X,Y,Z coordinate are given by the COMSOL variables 0.5*(solid.curlUX, ...Y, ...Z)
As any Curl operator, these are obtained from differences of two "derivable" variables, so round-off errors might appear
These variables are fields hence depending on (x,y,z,t) so you need to average them over a domain or boundary, and if you use edges in 3D you have to test how these operators heritage their values from average of the local boundaries.
And do not forget that the average of a twisting surface remains often close to "0" rotation, even at high angles ;)
Now if you want to express that on boundary coordinates you need to do an appropriate coordinate transform
Another way is to use the Global variables from the Rigid Connector BC but this has the drawback to make your part also 100% rigid so you should apply these BC to parts that do not flex, only acting as "rigid bodies" on your model
--
Good luck
Ivar
the angles w.r.t. the X,Y,Z coordinate are given by the COMSOL variables 0.5*(solid.curlUX, ...Y, ...Z)
As any Curl operator, these are obtained from differences of two "derivable" variables, so round-off errors might appear
These variables are fields hence depending on (x,y,z,t) so you need to average them over a domain or boundary, and if you use edges in 3D you have to test how these operators heritage their values from average of the local boundaries.
And do not forget that the average of a twisting surface remains often close to "0" rotation, even at high angles ;)
Now if you want to express that on boundary coordinates you need to do an appropriate coordinate transform
Another way is to use the Global variables from the Rigid Connector BC but this has the drawback to make your part also 100% rigid so you should apply these BC to parts that do not flex, only acting as "rigid bodies" on your model
--
Good luck
Ivar