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how to define a constraint deformation (use contact or a deformation field mask)
Posted Mar 2, 2011, 6:26 a.m. EST Structural Mechanics Version 4.0a 3 Replies
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Hi!
My problem is to deform a spherical layer, but the deformation shouldn't exist the outer layer, like a contact between these two layers.
1. Is it possible to define a contact between a solid and a shell layer in structure mechanics module? The outer layer is to be defined as shell.
2. If it's not possible for 1. I might have to define the outer layer as solid too, but this introduce too much computational efforts, since I am not interested in the outer layer. The only function for the
outer layer is to constrain the deformation of the inner layer.
Might it be better to generate a deformation field mask and use it as a constraint on the deformation of all the nodes at the surface of the inner layer?
That is, to define a deformation field for every nodes for the inner surface and imported as a function in Comsol, and to have it as a constraint for the displacement boundary condition.
Thanks.
XLi
My problem is to deform a spherical layer, but the deformation shouldn't exist the outer layer, like a contact between these two layers.
1. Is it possible to define a contact between a solid and a shell layer in structure mechanics module? The outer layer is to be defined as shell.
2. If it's not possible for 1. I might have to define the outer layer as solid too, but this introduce too much computational efforts, since I am not interested in the outer layer. The only function for the
outer layer is to constrain the deformation of the inner layer.
Might it be better to generate a deformation field mask and use it as a constraint on the deformation of all the nodes at the surface of the inner layer?
That is, to define a deformation field for every nodes for the inner surface and imported as a function in Comsol, and to have it as a constraint for the displacement boundary condition.
Thanks.
XLi
3 Replies Last Post Mar 13, 2011, 1:45 p.m. EDT
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Posted:
1 decade ago
Hi
sorry for the late reply, I have too many things to look after.
I'm not sure I understand your question fully, you are asking for a "contact" but is it an open boundary that might be in contact and might be free, or is it "just" a common boundary over which you want a continuity ?
I do not believe the "contact" physics is implemented between true "shell" physics and "solid" physics, this you need to contact support to get the confirmation, at least I do not know.
but if it is that you want to simulate a thin layer, as a shell, then it is possible to select only a boundary and give it "pseudo" thickness properties. I have never tried it out but it should be possible. But one need to validate carefully what one is doing to be sure it's fully understood. Furthermore there are free rotational degrees of freedom in the shell physics, that do not exist in "solid" I'm not 100% sure how to link these. Or if these are implicitly linked via the "solid" that does not have rotational degrees of freedom defined, still rigid body rotations are there, underlaying
--
Good luck
Ivar
sorry for the late reply, I have too many things to look after.
I'm not sure I understand your question fully, you are asking for a "contact" but is it an open boundary that might be in contact and might be free, or is it "just" a common boundary over which you want a continuity ?
I do not believe the "contact" physics is implemented between true "shell" physics and "solid" physics, this you need to contact support to get the confirmation, at least I do not know.
but if it is that you want to simulate a thin layer, as a shell, then it is possible to select only a boundary and give it "pseudo" thickness properties. I have never tried it out but it should be possible. But one need to validate carefully what one is doing to be sure it's fully understood. Furthermore there are free rotational degrees of freedom in the shell physics, that do not exist in "solid" I'm not 100% sure how to link these. Or if these are implicitly linked via the "solid" that does not have rotational degrees of freedom defined, still rigid body rotations are there, underlaying
--
Good luck
Ivar
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Posted:
1 decade ago
Hi!
Thanks a lot for your information!
I realized that what meant by "displacement mask" is to use penalty method to constraint the deformation now to let the inner layer deform outward the outer layer. In the begining I thought this should be an easier way than definining a contact between these two layers. Later on I found that this method is essentially equal to a contact, and the already existing contact defined in the software should be much better and easier than what I thought about the "displacement mask".
I asked the support, it's impossible to have shell contact with solid in the software.
"solid shells do not currently support contact modeling. This is something that we are looking at for future versions." (from the support).
But it's an interesting thing you proposed "I do not believe the "contact" physics is implemented between true "shell" physics and "solid" physics", did you mean that shell and solid can not get into contact physically? I know in other softwares like lsdyna, it should be possible to define a sliding only contact between shell and solid elements which means that shell and solid contact should be physically reasonable, ?
Thanks.
BR,
XLi
Thanks a lot for your information!
I realized that what meant by "displacement mask" is to use penalty method to constraint the deformation now to let the inner layer deform outward the outer layer. In the begining I thought this should be an easier way than definining a contact between these two layers. Later on I found that this method is essentially equal to a contact, and the already existing contact defined in the software should be much better and easier than what I thought about the "displacement mask".
I asked the support, it's impossible to have shell contact with solid in the software.
"solid shells do not currently support contact modeling. This is something that we are looking at for future versions." (from the support).
But it's an interesting thing you proposed "I do not believe the "contact" physics is implemented between true "shell" physics and "solid" physics", did you mean that shell and solid can not get into contact physically? I know in other softwares like lsdyna, it should be possible to define a sliding only contact between shell and solid elements which means that shell and solid contact should be physically reasonable, ?
Thanks.
BR,
XLi
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Posted:
1 decade ago
Hi
you can define a sliding contact, I believe but without the possibility to separate, by clearing the physics equations that are blocking the roller effect (quite model dependent , easier for a line along x,y,z , tougher for a skewed boundary in any direction
--
Good luck
Ivar
you can define a sliding contact, I believe but without the possibility to separate, by clearing the physics equations that are blocking the roller effect (quite model dependent , easier for a line along x,y,z , tougher for a skewed boundary in any direction
--
Good luck
Ivar