In examples/large_deformation/hyperelastic.py a rotation by displacements is applied. By using a similar function the vectors defining the force couples could be defined for dw_surface_ltr (IMHO). Does it make sense?
r.
 Reply message  From: "Andre Smit" <freev...@gmail.com> To: <sfepy...@googlegroups.com> Subject: Torque Date: Sat, Dec 18, 2010 05:10 What is the best way to apply a torque load to a model?
Andre
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Got the shear load to work ;)
It would be nice to be able to apply a shear traction though.
On Sat, Dec 18, 2010 at 1:48 AM, Robert Cimrman <cimr...@ntc.zcu.cz> wrote:
In examples/large_deformation/hyperelastic.py a rotation by displacements is applied. By using a similar function the vectors defining the force couples could be defined for dw_surface_ltr (IMHO). Does it make sense?
r.
 Reply message  From: "Andre Smit" <freev...@gmail.com> To: <sfepy...@googlegroups.com> Subject: Torque Date: Sat, Dec 18, 2010 05:10
What is the best way to apply a torque load to a model?
 Andre
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 Andre
Good!
dw_surface_ltr accepts traction vectors  that does not work for you?
r.
On 12/20/10 15:33, Andre Smit wrote:
Got the shear load to work ;)
It would be nice to be able to apply a shear traction though.
On Sat, Dec 18, 2010 at 1:48 AM, Robert Cimrman<cimr...@ntc.zcu.cz> wrote:
In examples/large_deformation/hyperelastic.py a rotation by displacements is applied. By using a similar function the vectors defining the force couples could be defined for dw_surface_ltr (IMHO). Does it make sense?
r.
 Reply message  From: "Andre Smit"<freev...@gmail.com> To:<sfepy...@googlegroups.com> Subject: Torque Date: Sat, Dec 18, 2010 05:10
What is the best way to apply a torque load to a model?
 Andre
hmm, just reread the original message  haven't tried but will.
On Mon, Dec 20, 2010 at 9:05 AM, Robert Cimrman <cimr...@ntc.zcu.cz> wrote:
Good!
dw_surface_ltr accepts traction vectors  that does not work for you?
r.
On 12/20/10 15:33, Andre Smit wrote:
Got the shear load to work ;)
It would be nice to be able to apply a shear traction though.
On Sat, Dec 18, 2010 at 1:48 AM, Robert Cimrman<cimr...@ntc.zcu.cz> wrote:
In examples/large_deformation/hyperelastic.py a rotation by displacements
is applied. By using a similar function the vectors defining the force couples could be defined for dw_surface_ltr (IMHO). Does it make sense?
r.
 Reply message  From: "Andre Smit"<freev...@gmail.com> To:<sfepy...@googlegroups.com> Subject: Torque Date: Sat, Dec 18, 2010 05:10
What is the best way to apply a torque load to a model?
 Andre
 You received this message because you are subscribed to the Google Groups "sfepydevel" group. To post to this group, send email to sfepy...@googlegroups.com. To unsubscribe from this group, send email to sfepydevel...@googlegroups.com<sfepydevel%...@googlegroups.com> . For more options, visit this group at http://groups.google.com/group/sfepydevel?hl=en.
 Andre
I know this is an old thread, but anyone know how to get a shear traction on a surface using dw_surface_ltr?
Ben
On 03/07/2018 09:04 PM, Ben Melosh wrote:
I know this is an old thread, but anyone know how to get a shear traction on a surface using dw_surface_ltr?
The dw_surface_ltr can work with a given scalar pressure, a traction vector, or a stress tensor, see [1]. So passing a traction vector would work for you, right? If you need to know surface facet normals in each quadrature point to determine the tangent plane, that is also possible to get in the user function for setting the material parameters:
geo, _ = term.get_mapping(term.args[1])
def get_traction(ts, coor, mode=None, equations=None, term=None, problem=None, **kwargs): if mode == 'qp': geo, _ = term.get_mapping(term.args[1]) print geo.normal
...
Is this what you need?
r.
[1] http://sfepy.org/docdevel/src/sfepy/terms/terms_surface.html#sfepy.terms.te...
Yes, I think passing a traction vector would work. I'm not sure how to calculate the traction vector from the output from geo.normal which appears to be a list of vectors? Is there a function to do this?
thanks b
On 03/09/2018 01:55 AM, Ben Melosh wrote:
Yes, I think passing a traction vector would work. I'm not sure how to calculate the traction vector from the output from geo.normal which appears to be a list of vectors? Is there a function to do this?
Yes, it is a list of vectors  normals of the surface. To get vectors tangent to the surface, you can use [1]. There is no function to compute the shear traction.
r.
[1] http://sfepy.org/docdevel/src/sfepy/linalg/geometry.html?highlight=get_perp...
participants (4)

Andre Smit

Ben Melosh

Robert Cimrman

Robert Cimrman