Mailman 3 November 2015 - SfePy

Material Parameters of Individual Nodes
by derj...＠web.de 12 Apr '22

12 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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Re: Torque
by Robert Cimrman 10 Mar '18

10 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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1D line elements in SfePy
by Nimish 22 Jan '16

22 Jan '16

I am currrently looking for FEM packages to help me solve a system of beams and columns, basically a collection of 1D bernoulli/timoshenko line elements. I started reading SfePy docs and i am getting the idea that doing the above is not really possible here, am i right? Are only 2D area elements permitted in SfePy? Or is there any direct support for solving 1D line elements too.. Cheers Nimish

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cannot set toolkit to wx because it has already been set to qt4
by silesa...＠hotmail.com 16 Dec '15

16 Dec '15

I have made an inline instalation of sfepy-2013.3 on fedora22 , I run the tests and I have only 3 failed, they maybe related to the parallel option since I don't have instaled that option. I have python 2.7.10, mayavi 4.4.3, VTK 6.1.0, Qt 4.8.6 Either on the python or ipython window when I try to import: *from sfepy.postprocess.viewer import Viewe*r I get the following message, *cannot set toolkit to wx because it has already been set to qt4* and of course any postprocessing will fail

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SfePy distributed load
by nayan...＠gmail.com 01 Dec '15

01 Dec '15

Hello Robert, I am trying to simulate a rectangular block with the fixed bottom and loaded at the top by an area force. I have following doubts. Please clarify 1.How to consider the area force. 2.Which elastic equation should I use? I am not finding any equation for area loads. 3.I'm sharing my problem description file. Kindly look into it and help me understand. I am very new to SfePy. from sfepy.mechanics.matcoefs import lame_from_youngpoisson from sfepy.discrete.fem.utils import refine_mesh from sfepy import data_dir # Tell SfePy to use our .mesh file filename_mesh = data_dir + '/meshes/3d/block.mesh' # Tell SfePy where u want to save the output output_dir = '.' # Material parameters. young = 200000.0 # Young's modulus [MPa] poisson = 0.26 # Poisson's ratio options = { 'output_dir' : output_dir, } #Regions are used to define the boundary conditions, the domains of terms and materials etc. regions = { 'Omega' : 'all', 'Bottom' : ('vertices in (y=0)', 'facet'), 'Top':('vertices in (y=1)', 'facet'), } #Define constitutive parameters (e.g. stiffness, permeability, or viscosity), #Also other non-field arguments of terms (e.g. known traction or volume forces). materials = { 'Steel' : ({ 'lam' : lame_from_youngpoisson(young, poisson)[0], 'mu' : lame_from_youngpoisson(young, poisson)[1], },), 'Load' : ({'.val' : [0.0, -5.0,0.0]},), } #FE field.Here 'real' is datatype,'3' is dof per node, field is defined over omega & '1' is approximation order fields = { 'displacement': ('real', '3', 'Omega', 1), } #Here we use linear elastic spring equation equations = { 'balance_of_forces' : """dw_lin_elastic_iso.2.Omega(Steel.lam, Steel.mu, v, u ) = dw_point_load.0.Top(Load.val, v)""", } # Specify the variables that use the FE approximation given by the specified field variables = { 'u' : ('unknown field', 'displacement', 0), 'v' : ('test field', 'displacement', 'u'), } #Since the bottom is fixed corresponding nodal displacement are zero ebcs = { 'Fixed' : ('Bottom', {'u.all' : 0.0}), } #In SfePy, a non-linear solver has to be specified even when solving a linear problem. #The linear problem is/should be then solved in one iteration of the nonlinear solver solvers = { 'ls' : ('ls.scipy_direct', {}), 'newton' : ('nls.newton', { 'i_max' : 1,# Number of iterations 'eps_a' : 1e-6, }), } Thanks in advance, Nayan M

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Re: [sfepy-devel] SfePy help
by Robert Cimrman 27 Nov '15

27 Nov '15

Hi Madhu, How did you install sfepy? r. On 11/19/2015 07:18 PM, Madhu Mahadevappa wrote: > Dear Robert, > Thank you very much for the reply. I'm Using Canopy. Please let me know > how and where to find the SfePy directory? I'm sorry if it is a stupid > question. > > Regards, > Madhu > > On Thursday, 19 November 2015 15:23:43 UTC+5:30, Robert Cimrman wrote: >> >> Hello Madhu, >> >> Try using sfepy in-place build [1]. This example is in SfePy, so you can >> run it >> simply by (in the sfepy source directory): >> >> python simple.py examples/linear_elasticity/its2D_2.py >> >> But feel free to copy it elsewhere (as long as you stay in the sfepy >> source >> directory when running commands. >> >> You can also use your file, but correct the path, if both the example and >> the >> mesh are in the same directory: >> >> filename_mesh = 'its2D.mesh' >> >> The syntax error is strange - how/where did you run the command? Also, do >> not >> mix \ and / characters in paths. >> >> Does that help? >> >> r. >> [1] http://sfepy.org/doc-devel/installation.html#in-place-build >> >> On 11/18/2015 07:00 PM, Madhu Mahadevappa wrote: >>> Hello, >>> I'm Madhu and very new to Sfepy, learning this for my Master Thesis. >> I'm >>> trying to run the example given in the primer but getting an >> error.Please >>> help me with this. >>> 1. I'm trying to invoke SfePy with the command 'E:|Solution/simple.py >>> its2D.py' . My Problem definition file and .mesh file are located in my >> E >>> drive with a folder named Solution. When I run this, I'm getting the >>> following error >>> "" >>> E:\Solution/simple.py its2D.py >>> ^ >>> SyntaxError: invalid syntax >>> >>> "" >>> 2. I have attached both the problem definition file and .mesh file I >> have >>> been trying from past 2 days to rectify but I couln't. Kindly help me. >>> >>> Regards, >>> Madhu >>> >> >> >

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SfePy help
by Madhu Mahadevappa 19 Nov '15

19 Nov '15

Hello, I'm Madhu and very new to Sfepy, learning this for my Master Thesis. I'm trying to run the example given in the primer but getting an error.Please help me with this. 1. I'm trying to invoke SfePy with the command 'E:|Solution/simple.py its2D.py' . My Problem definition file and .mesh file are located in my E drive with a folder named Solution. When I run this, I'm getting the following error "" E:\Solution/simple.py its2D.py ^ SyntaxError: invalid syntax "" 2. I have attached both the problem definition file and .mesh file I have been trying from past 2 days to rectify but I couln't. Kindly help me. Regards, Madhu

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Compiling errors
by Adolfo Rodriguez 12 Nov '15

12 Nov '15

After doing python setup.py build_ext --inplace --compiler=mingw32 I get some compiling errors for file fmfield.c. See the attached snapshot <https://lh3.googleusercontent.com/--iKxAewkxL8/VkPFWwt7b7I/AAAAAAAADsI/KMCq…>

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How to specify material constants for regions of type facet
by Geoff Wright 10 Nov '15

10 Nov '15

I just updated sfepy to the latest master (previous version was about 1 year old) and I'm having trouble evaluating an FEM model that was working with the old version. The full script is pretty long so I will try to summarize here. It seems that a region of facet type is no longer able to evaluate it's material properties where the material properties were defined on other related regions of cell type. Robert, do you know off hand of any changes to Region or Material that may have broken this? Otherwise, I can try to reproduce it in a simpler use case, for debugging.. anyway here is a description of whats happening: A material is defined as follows: self.matP = Material('elecProps', kind='stationary', values={'sigma' : { 'BloodPool' : sigma_blood, 'Tissue' : sigma_tissue}}) One of the terms is as follows: probeFlux = Term.new('dw_surface_integrate(elecProps.sigma, s)', self.integral, self.probeSurf, elecProps=self.matP, s=self.s) where self.probeSurf is defined as follows (it contains no cells, only facets): self.probeSurf = self.domain.create_region('ProbeSurf', 'r.Probe *f r.Tissue', kind='facet', parent='Tissue') When I run the full script I get the following backtrace: /usr/local/lib/python2.7/dist-packages/sfepy/discrete/problem.pyc in solve(self, state0, nls_status, ls_conf, nls_conf, force_values, var_data) 1012 self.equations.set_data(var_data, ignore_unknown=True) 1013 -> 1014 self.update_materials() 1015 state0.apply_ebc(force_values=force_values) 1016 /usr/local/lib/python2.7/dist-packages/sfepy/discrete/problem.pyc in update_materials(self, ts, mode, verbose) 528 self.update_time_stepper(ts) 529 self.equations.time_update_materials(self.ts, mode=mode, --> 530 problem=self, verbose=verbose) 531 532 /usr/local/lib/python2.7/dist-packages/sfepy/discrete/equations.pyc in time_update_materials(self, ts, mode, problem, verbose) 318 """ 319 self.materials.time_update(ts, self, mode=mode, problem=problem, --> 320 verbose=verbose) 321 322 def setup_initial_conditions(self, ics, functions=None): /usr/local/lib/python2.7/dist-packages/sfepy/discrete/materials.pyc in time_update(self, ts, equations, mode, problem, verbose) 55 for mat in self: 56 if verbose: output(' ', mat.name) ---> 57 mat.time_update(ts, equations, mode=mode, problem=problem) 58 if verbose: output('...done in %.2f s' % (time.clock() - tt)) 59 /usr/local/lib/python2.7/dist-packages/sfepy/discrete/materials.pyc in time_update(self, ts, equations, mode, problem) 304 305 for key, term in self.iter_terms(equations): --> 306 self.update_data(key, ts, equations, term, problem=problem) 307 308 self.update_special_data(ts, equations, problem=problem) /usr/local/lib/python2.7/dist-packages/sfepy/discrete/materials.pyc in update_data(self, key, ts, equations, term, problem) 220 data = self.function(ts, coors, mode='qp', 221 equations=equations, term=term, problem=problem, --> 222 **self.extra_args) 223 224 self.set_data(key, qps, data) /usr/local/lib/python2.7/dist-packages/sfepy/discrete/functions.pyc in __call__(self, *args, **kwargs) 32 _kwargs = dict(kwargs) 33 _kwargs.update(self.extra_args) ---> 34 return self.function(*args, **_kwargs) 35 36 def set_function(self, function, is_constant=False): /usr/local/lib/python2.7/dist-packages/sfepy/discrete/functions.pyc in get_constants(ts, coors, mode, term, problem, **kwargs) 112 region = problem.domain.regions[rkey] 113 rval = nm.array(rval, dtype=nm.float64, ndmin=3) --> 114 ii = term.region.get_cell_indices(region.cells) 115 matdata[ii] = rval 116 /usr/local/lib/python2.7/dist-packages/sfepy/discrete/common/region.pyc in get_cell_indices(self, cells, true_cells_only) 600 to facets are returned if the region itself contains no cells. 601 """ --> 602 fcells = self.get_cells(true_cells_only=true_cells_only) 603 604 ii = nm.searchsorted(fcells, cells) /usr/local/lib/python2.7/dist-packages/sfepy/discrete/common/region.pyc in get_cells(self, true_cells_only) 579 msg = 'region %s has not true cells! (has kind: %s)' \ 580 % (self.name, self.kind) --> 581 raise ValueError(msg) 582 583 else: ValueError: region ProbeSurf has not true cells! (has kind: facet)

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