Dear Firedrakers, I would like to model a bi-material medium. One can think of an elasticity problem where the domain is composed of 2 parts, one being made of steel and the other one of rubber. Then I would like to assign different Lamé coefficients to these parts. I do not find such an example in Firedrake tests. Could you please give me some piece of advice? Best regards, Nicolas
Dear Nicolas, You can simply use a DG0 Function for each Lame coefficient, and interpolate a spatially varying expression into it. For a case like this where you want a step function in the coefficient, you probably want to use a ufl.conditional (effectively an “if” expression) in the expression you interpolate. Regards, David From: <firedrake-bounces@imperial.ac.uk> on behalf of Karin&NiKo <niko.karin@gmail.com> Date: Wednesday, 27 May 2020 at 07:31 To: firedrake <firedrake@imperial.ac.uk> Subject: [firedrake] Bi-material example Dear Firedrakers, I would like to model a bi-material medium. One can think of an elasticity problem where the domain is composed of 2 parts, one being made of steel and the other one of rubber. Then I would like to assign different Lamé coefficients to these parts. I do not find such an example in Firedrake tests. Could you please give me some piece of advice? Best regards, Nicolas
Dear Colin and David, Thank you very much. I am trying this. Le mer. 27 mai 2020 à 09:26, Ham, David A <david.ham@imperial.ac.uk> a écrit :
Dear Nicolas,
You can simply use a DG0 Function for each Lame coefficient, and interpolate a spatially varying expression into it. For a case like this where you want a step function in the coefficient, you probably want to use a ufl.conditional (effectively an “if” expression) in the expression you interpolate.
Regards,
David
*From: *<firedrake-bounces@imperial.ac.uk> on behalf of Karin&NiKo < niko.karin@gmail.com> *Date: *Wednesday, 27 May 2020 at 07:31 *To: *firedrake <firedrake@imperial.ac.uk> *Subject: *[firedrake] Bi-material example
Dear Firedrakers,
I would like to model a bi-material medium. One can think of an elasticity problem where the domain is composed of 2 parts, one being made of steel and the other one of rubber. Then I would like to assign different Lamé coefficients to these parts.
I do not find such an example in Firedrake tests.
Could you please give me some piece of advice?
Best regards,
Nicolas
Dear Colin and David, I have been trying things and looking all over the place but I cannot get to do what I would like to. So please allow me to come back to you in order to make my question clearer. I have a Gmsh 2D mesh where I have defined Physical Surface corresponding to regions having different values of the Lamé's coefficients. Then I would like to set the values of these coefficients with respect to the names or numbers of the regions in my bilinear form. Said that way, it seems obvious but I couldn't find similar tests or examples. Thanks for your help. Nicolas Le mer. 27 mai 2020 à 09:37, Karin&NiKo <niko.karin@gmail.com> a écrit :
Dear Colin and David, Thank you very much. I am trying this.
Le mer. 27 mai 2020 à 09:26, Ham, David A <david.ham@imperial.ac.uk> a écrit :
Dear Nicolas,
You can simply use a DG0 Function for each Lame coefficient, and interpolate a spatially varying expression into it. For a case like this where you want a step function in the coefficient, you probably want to use a ufl.conditional (effectively an “if” expression) in the expression you interpolate.
Regards,
David
*From: *<firedrake-bounces@imperial.ac.uk> on behalf of Karin&NiKo < niko.karin@gmail.com> *Date: *Wednesday, 27 May 2020 at 07:31 *To: *firedrake <firedrake@imperial.ac.uk> *Subject: *[firedrake] Bi-material example
Dear Firedrakers,
I would like to model a bi-material medium. One can think of an elasticity problem where the domain is composed of 2 parts, one being made of steel and the other one of rubber. Then I would like to assign different Lamé coefficients to these parts.
I do not find such an example in Firedrake tests.
Could you please give me some piece of advice?
Best regards,
Nicolas
On Mon, 1 Jun 2020 at 18:59, Karin&NiKo <niko.karin@gmail.com> wrote:
Dear Colin and David,
I have been trying things and looking all over the place but I cannot get to do what I would like to. So please allow me to come back to you in order to make my question clearer. I have a Gmsh 2D mesh where I have defined Physical Surface corresponding to regions having different values of the Lamé's coefficients. Then I would like to set the values of these coefficients with respect to the names or numbers of the regions in my bilinear form. Said that way, it seems obvious but I couldn't find similar tests or examples.
If you make a dg0 function V = FunctionSpace(mesh, "DG", 0) f = Function(V) You can interpolate onto subsets defined by the physical surface ids: f.interpolate(valA, subset=mesh.cell_subset(idA)) Etc... This is rather badly documented sorry. Lawrence Thanks for your help.
Nicolas
Le mer. 27 mai 2020 à 09:37, Karin&NiKo <niko.karin@gmail.com> a écrit :
Dear Colin and David, Thank you very much. I am trying this.
Le mer. 27 mai 2020 à 09:26, Ham, David A <david.ham@imperial.ac.uk> a écrit :
Dear Nicolas,
You can simply use a DG0 Function for each Lame coefficient, and interpolate a spatially varying expression into it. For a case like this where you want a step function in the coefficient, you probably want to use a ufl.conditional (effectively an “if” expression) in the expression you interpolate.
Regards,
David
*From: *<firedrake-bounces@imperial.ac.uk> on behalf of Karin&NiKo < niko.karin@gmail.com> *Date: *Wednesday, 27 May 2020 at 07:31 *To: *firedrake <firedrake@imperial.ac.uk> *Subject: *[firedrake] Bi-material example
Dear Firedrakers,
I would like to model a bi-material medium. One can think of an elasticity problem where the domain is composed of 2 parts, one being made of steel and the other one of rubber. Then I would like to assign different Lamé coefficients to these parts.
I do not find such an example in Firedrake tests.
Could you please give me some piece of advice?
Best regards,
Nicolas
_______________________________________________ firedrake mailing list firedrake@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/firedrake
Thank you very much Lawrence. This is exactly what I want! Le lun. 1 juin 2020 20:11, Lawrence Mitchell <wence@gmx.li> a écrit :
On Mon, 1 Jun 2020 at 18:59, Karin&NiKo <niko.karin@gmail.com> wrote:
Dear Colin and David,
I have been trying things and looking all over the place but I cannot get to do what I would like to. So please allow me to come back to you in order to make my question clearer. I have a Gmsh 2D mesh where I have defined Physical Surface corresponding to regions having different values of the Lamé's coefficients. Then I would like to set the values of these coefficients with respect to the names or numbers of the regions in my bilinear form. Said that way, it seems obvious but I couldn't find similar tests or examples.
If you make a dg0 function
V = FunctionSpace(mesh, "DG", 0) f = Function(V)
You can interpolate onto subsets defined by the physical surface ids:
f.interpolate(valA, subset=mesh.cell_subset(idA))
Etc...
This is rather badly documented sorry.
Lawrence
Thanks for your help.
Nicolas
Le mer. 27 mai 2020 à 09:37, Karin&NiKo <niko.karin@gmail.com> a écrit :
Dear Colin and David, Thank you very much. I am trying this.
Le mer. 27 mai 2020 à 09:26, Ham, David A <david.ham@imperial.ac.uk> a écrit :
Dear Nicolas,
You can simply use a DG0 Function for each Lame coefficient, and interpolate a spatially varying expression into it. For a case like this where you want a step function in the coefficient, you probably want to use a ufl.conditional (effectively an “if” expression) in the expression you interpolate.
Regards,
David
*From: *<firedrake-bounces@imperial.ac.uk> on behalf of Karin&NiKo < niko.karin@gmail.com> *Date: *Wednesday, 27 May 2020 at 07:31 *To: *firedrake <firedrake@imperial.ac.uk> *Subject: *[firedrake] Bi-material example
Dear Firedrakers,
I would like to model a bi-material medium. One can think of an elasticity problem where the domain is composed of 2 parts, one being made of steel and the other one of rubber. Then I would like to assign different Lamé coefficients to these parts.
I do not find such an example in Firedrake tests.
Could you please give me some piece of advice?
Best regards,
Nicolas
_______________________________________________ firedrake mailing list firedrake@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/firedrake
participants (3)
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Ham, David A
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Karin&NiKo
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Lawrence Mitchell