SfePy September 2016

sfepy@python.org

4 participants
14 discussions

Material Parameters of Individual Nodes
by derj...＠web.de 11 Apr '22

11 Apr '22

Hello! It's a great tool you built there! I'd like to use it for some kind of topology optimisation. Is there an "idiomatic" way to set the material parameters of individual nodes? Thank you very much! JonnyB

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Calculate total force from cauchy stress
by Patricia Garcia Cañadilla 17 Jan '19

17 Jan '19

Dear Robert, I have a 2D body of hyperelastic material which contracts and I would like to compute the total force developed by the body from the cauchy stress. I am trying to follow some of your indications I found in this group, but I still couldn't make it works. Could you please help me to fix the problem? I am getting the following error: key = (region.name, integral.order, integration) AttributeError: 'dict' object has no attribute 'name' I am trying to do the following, inside stress_strain post-processing function: def stress_strain(out, problem, state, extend = False ): from sfepy.base.base import Struct from sfepy.mechanics.tensors import StressTransform from sfepy.mechanics.tensors import transform_data from sfepy.discrete.common.mappings import get_normals ev = problem.evaluate field = problem.fields['displacement'] region = problem.domain.regions['Gamma'] integral = problem.integrals['i2'] n = get_normals(field,integral,regions) stress = ev('dw_tl_fib_a.1.Omega(f1.fmax, f1.eps_opt, f1.s, f1.fdir, f1.act, v, u )',mode='qp', term_mode= 'stress'); F = ev('ev_def_grad.1.Omega(u)',mode='el_avg'); transform = StressTransform(F) Cstress = transform.get_cauchy_from_2pk(stress) T = Cstress*n; Force = ev('ev_surface_integrate.2.Gamma(T)') And here it is part of the problem configuration file. fields = { 'displacement': ('real', 'vector', 'Omega', 1), } materials = { 'solid' : (None, 'get_elastic_pars'), 'load' : (None, 'linear_tension'), 'f1' : 'get_pars_fibres1', } variables = { 'u': ('unknown field', 'displacement', 0), 'v': ('test field', 'displacement', 'u'), } regions = { 'Omega' : 'all', 'Fix1' : ('vertices in x < %.10f' % (fix_point + eps2), 'facet'), 'Fix2' : ('vertices in x > %.10f' % (fix_point - eps2), 'facet'), 'Fix' : ('r.Fix1 *v r.Fix2', 'facet'), 'Gamma' : ('vertices of surface','edge'), } ebcs = { 'fixb' : ('Fix', {'u.all' : 0.0}), } integrals = { 'i1' : ('v', 1), 'i2' : ('s', 2), }

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Re: Torque
by Robert Cimrman 09 Mar '18

09 Mar '18

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...(a)gmail.com> To: <sfepy...(a)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 "sfepy-devel" group. To post to this group, send email to sfepy...(a)googlegroups.com. To unsubscribe from this group, send email to sfepy-devel...(a)googlegroups.com. For more options, visit this group at http://groups.google.com/group/sfepy-devel?hl=en.

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new interactive example with time stepping
by Robert Cimrman 13 Mar '17

13 Mar '17

Hi, I have just updated the time stepping solvers in sfepy for interactive use, as demonstrated in the new example [1]. For basic use, ignore the probing code - the time stepper can be used as simply as: tss = SimpleTimeSteppingSolver({'t0' : 0.0, 't1' : 100.0, 'n_step' : 11}, problem=problem) tss.init_time() for step, time, state in tss(): pass r. [1] http://sfepy.org/doc-devel/examples/diffusion/time_poisson_interactive.html

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Problem with Iterative solver
by Nikhil Vaidya 18 Oct '16

18 Oct '16

Hello, I am trying to solve a poiseuille flow example. I want to make use of the ls.scipy_iterative sovler. I am using the cg method. The problem definition file, mesh and the vtk output are attached. Also attached is a plot of the pressure and axial flow velocity along the axis of the pipe. As you can see, the solution is completely non-physical. The same case runs fine with the scipy_direct solver. What am I doing wrong? Best regards, Nikhil

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Outlet Boundary Conditions for Navier Stokes
by Nikhil Vaidya 18 Oct '16

18 Oct '16

Hello! I am solving for steady laminar flow through a pipe. The issue I am facing is the following: I have given a velocity boundary condition at the pipe inlet. For the outlet, I examined the following two cases: 1) Pressure boundary condition at outlet. 2) No boundary condition prescribed at outlet. For both cases, I get a strange jump in the velocity at the pipe outlet. In the attached files you can see the velocity and pressure plotted along the axis(from inlet to outlet) of the pipe. Why do I see a jump in the velocity for both cases? How do I specify outlet conditions in sfepy? Another observation that I have made is that for case 1, there is a jump in the pressure value at the outlet. In case 2, this pressure-jumps goes away. Best regards, Nikhil

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ANN: SfePy 2016.3
by Robert Cimrman 30 Sep '16

30 Sep '16

I am pleased to announce release 2016.3 of SfePy. Description ----------- SfePy (simple finite elements in Python) is a software for solving systems of coupled partial differential equations by the finite element method or by the isogeometric analysis (limited support). It is distributed under the new BSD license. Home page: http://sfepy.org Mailing list: http://groups.google.com/group/sfepy-devel Git (source) repository, issue tracker: http://github.com/sfepy/sfepy Highlights of this release -------------------------- - Python 3 support - testing with Travis CI - new classes for homogenized coefficients - using argparse instead of optparse For full release notes see http://docs.sfepy.org/doc/release_notes.html#id1 (rather long and technical). Cheers, Robert Cimrman --- Contributors to this release in alphabetical order: Robert Cimrman Jan Heczko Thomas Kluyver Vladimir Lukes

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Error in 2d Navier Stokes
by Nikhil Vaidya 16 Sep '16

16 Sep '16

Hi, I am trying to run a 2d laminar pipe flow simulation. I get the following error when I run simple.py: sfepy: left over: ['verbose', '__builtins__', '__file__', 'absolute_import', '__name__', '__package__', '_filename', '__doc__'] Traceback (most recent call last): File "/scratch/sfepy/simple.py", line 170, in <module> main() File "/scratch/sfepy/simple.py", line 155, in main define_args=options.define_args) File "/scratch/sfepy/sfepy/base/conf.py", line 383, in from_file_and_options override=override, setup=setup) File "/scratch/sfepy/sfepy/base/conf.py", line 369, in from_file override=override, setup=setup) File "/scratch/sfepy/sfepy/base/conf.py", line 415, in __init__ required=required, other=other) File "/scratch/sfepy/sfepy/base/conf.py", line 433, in setup self.transform_input() File "/scratch/sfepy/sfepy/base/conf.py", line 506, in transform_input self.__dict__[key] = transform(self.__dict__[key]) File "/scratch/sfepy/sfepy/base/conf.py", line 187, in transform_fields if c2.dtype in dtypes: TypeError: unhashable type: 'dict' the problem setup file and mesh are attached. Could you tell me where I am going wrong? Best regards, Nikhil

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Tetrahedral mesh with prism layer
by Nikhil Vaidya 16 Sep '16

16 Sep '16

Hello! Does sfepy support a tetrahedral mesh with a prism layer adjacent to selected boundaries of the geometry? If yes, what should the medit mesh file containing two different sorts of elements look like? Best regards, Nikhil

2 1

User defined functions
by Nikhil Vaidya 15 Sep '16

15 Sep '16

Hello! I want to set a user defined function as a boundary condition. For example, ebc_1 = { 'ebc_inlet' : ('inlet', {'u.[0,2]' : 0, 'u.1' : myfunc}, } myfunc(ts, coors, **kwargs): ... what type of an object is coors? how can I write the x, y and z coordinates in terms of the variable coors? Best regards, Nikhil

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SfePy September 2016