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Rotated Coordinate System
Posted 1 févr. 2011, 12:43 UTC−5 6 Replies
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I am having trouble understanding how comsol implements a rotated coordinate system. For the 3D case, I understand how Euler angles define the new coordinate system. However, for the 2D case, the definition of the system is less clear to me. I understand that a rotation is performed about an axis, but the terminology has me stuck.
My goal is to define coordinate systems for each layer of a multilayer composite plate because the orthotropic material used in each layer has a different orientation.
Does anyone have a clear explanation of how rotated coordinate systems work in 2D?
Thanks,
Matt
My goal is to define coordinate systems for each layer of a multilayer composite plate because the orthotropic material used in each layer has a different orientation.
Does anyone have a clear explanation of how rotated coordinate systems work in 2D?
Thanks,
Matt
6 Replies Last Post 24 févr. 2014, 01:46 UTC−5
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Posted:
1 decade ago
Hi
I would say as in 3D. In V4.1 latest patch there are many new (plot => More) plot options for coordinate systems and arrow representations to help identify the direction of your coordinates. In 2D by default you have only Rz (perpendicular out of the screen/paper dirction). then by turning on the equations you can see how COMSOL handles these equations.
ie. in 3D a cylindrical cooridnate system at (0,0,0) axis =Z you have:
sys2.r = sqrt(x^2+y^2)
sys2.phi = atan2(y,x) and
sys.a = z
These equations are not written out like that, but you find them all (somewhat scattered around) in the doc (at least in the <= 3.5a and the >= 4.1 doc ;) See with cour local rep to upgrade to the current patched 4.1, its much smoother to use than the early 4.0
--
Good luck
Ivar
I would say as in 3D. In V4.1 latest patch there are many new (plot => More) plot options for coordinate systems and arrow representations to help identify the direction of your coordinates. In 2D by default you have only Rz (perpendicular out of the screen/paper dirction). then by turning on the equations you can see how COMSOL handles these equations.
ie. in 3D a cylindrical cooridnate system at (0,0,0) axis =Z you have:
sys2.r = sqrt(x^2+y^2)
sys2.phi = atan2(y,x) and
sys.a = z
These equations are not written out like that, but you find them all (somewhat scattered around) in the doc (at least in the <= 3.5a and the >= 4.1 doc ;) See with cour local rep to upgrade to the current patched 4.1, its much smoother to use than the early 4.0
--
Good luck
Ivar
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Posted:
1 decade ago
Hi Ivar,
I have just upgraded to the most recent 4.1 patch. Thanks for the info about visualizing the coordinate systems in plots.
I am trying to define anisotropic materials In a 2D plane strain situation where each layer in a plate has a different orientation (e.g., composite materials). Is it possible to define a coordinate system for the 2D case where the system is rotated about the global y-axis? I suppose I could transform the Elasticity matrix and define a new material for each layer, but it would be nice to be able to use a single material and multiple coordinate systems.
Thanks,
Matt
I have just upgraded to the most recent 4.1 patch. Thanks for the info about visualizing the coordinate systems in plots.
I am trying to define anisotropic materials In a 2D plane strain situation where each layer in a plate has a different orientation (e.g., composite materials). Is it possible to define a coordinate system for the 2D case where the system is rotated about the global y-axis? I suppose I could transform the Elasticity matrix and define a new material for each layer, but it would be nice to be able to use a single material and multiple coordinate systems.
Thanks,
Matt
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Posted:
1 decade ago
Hi,
I'm using 4.2a, and can't figure out how to plot the axes of my co-ordinate systems in order to judge whether I have them in the direction I intended - it always just seems to plot the global axes on my 3D results plots. I have hunted high and low, but nothing seems to make a difference.
Where is the the 'plot->more' option you mentioned, please (if it still exists)?
Best Regards,
Peter
I'm using 4.2a, and can't figure out how to plot the axes of my co-ordinate systems in order to judge whether I have them in the direction I intended - it always just seems to plot the global axes on my 3D results plots. I have hunted high and low, but nothing seems to make a difference.
Where is the the 'plot->more' option you mentioned, please (if it still exists)?
Best Regards,
Peter
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Posted:
1 decade ago
Hi
indeed plotting coordinate systems is a bit tricky today, you need to have a geometry, physics and a solver node (but your physics does not need to be complete BCs might not yet be fully defined) + use the post-processing to get there,
The easiest is to: load you initial conditions: 1) "Study - show default solver" then 2) right click "Study ... Solver Configuration - Solver - Dependent Variables + Compute to selected.
then Results right click plot (3D or 2D depends on your model, use the "domain" dimension) Right click the plot group and use "more plots" and select one of the Coordinate system plots, then select the one coordinate system to show
--
Good luck
Ivar
indeed plotting coordinate systems is a bit tricky today, you need to have a geometry, physics and a solver node (but your physics does not need to be complete BCs might not yet be fully defined) + use the post-processing to get there,
The easiest is to: load you initial conditions: 1) "Study - show default solver" then 2) right click "Study ... Solver Configuration - Solver - Dependent Variables + Compute to selected.
then Results right click plot (3D or 2D depends on your model, use the "domain" dimension) Right click the plot group and use "more plots" and select one of the Coordinate system plots, then select the one coordinate system to show
--
Good luck
Ivar
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Posted:
1 decade ago
Ivan,
Thank you. That does the trick nicely.
Happy Christmas!
Peter
Thank you. That does the trick nicely.
Happy Christmas!
Peter
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Posted:
1 decade ago
Dear all
Hi
I import model from solidworks that is rotated 45 degree around of X axis, and after set up procedure in COMSOL, i don't know how i can make an angle for my load which being aligned with my rotated model. i define rigid connector and impose load on it but this load is aligned with Z direction
How would I change load angle to being aligned with rigid connector of my model
Any help appreciated
Mostakhdemin
Hi
I import model from solidworks that is rotated 45 degree around of X axis, and after set up procedure in COMSOL, i don't know how i can make an angle for my load which being aligned with my rotated model. i define rigid connector and impose load on it but this load is aligned with Z direction
How would I change load angle to being aligned with rigid connector of my model
Any help appreciated
Mostakhdemin