Mailman 3 July 2018 - SfePy

Material Parameters of Individual Nodes
by derj...＠web.de April 12, 2022

April 12, 2022

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 Jan. 17, 2019

Jan. 17, 2019

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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Navier - Stokes at high viscosity
by Ben Melosh Nov. 6, 2018

Nov. 6, 2018

I am trying to model Stokes flow at very high viscosities (~10^20), from my results it looks like I cannot achieve this and am better suited using viscosities of ~10^5 or so. I know there is this older post [1] which states: "A word of warning though: SfePy does not have a dedicated Navier-Stokes solver (the Newton (+ and direct) solver use that is in the navier_stokes.py example is rather naive, and works for small problems with only, with viscosity "high enough")" Has there been a different solver implemented since this was posted? If not, what do you recommend to work with such large viscosities? Thank you [1] "Problem with the mesh while trying to solve the Navier Stokes equations with sfepy"

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Re: How to output vtk or h5 of compare_elastic_materials.py
by pyontaku14 July 31, 2018

July 31, 2018

Hi, I tried to output stress and strain of compare_elastic_materials.py. I edited the original to the attached. But stress and strain did not come out to vtk. Is there any way to output stress and strain of compare_elastic_materials.py? Best regards, Takuo Fujita 2018年6月12日(火) 21:54 藤田 <fujikko(a)adagio.ocn.ne.jp>: > Hi Robert, > > Thank you for your answer. > I obtained vtk files. > Thank you, > > Takuo Fujita > > 2018年6月12日(火) 15:53 Robert Cimrman <cimrman3(a)ntc.zcu.cz>: > >> On 06/11/2018 03:51 PM, pyontaku14 . wrote: >> > Hi, >> > >> > Is there any way to output vtk or h5 of compare_elastic_materials.py? >> >> Sure, just change "save_results=False" to "save_results=True" in >> solve_branch(), line 150. You might also want to change >> problem.output_dir to >> different names in each run so that the results are not overwritten. >> >> r. >> _______________________________________________ >> SfePy mailing list -- sfepy(a)python.org >> To unsubscribe send an email to sfepy-leave(a)python.org >> https://mail.python.org/mm3/mailman3/lists/sfepy.python.org/ >> >

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Creating and Adding New Terms
by underwatergary＠gmail.com July 26, 2018

July 26, 2018

Hello there! First of all let me just say that SfePy is such an amazing software and is helping the visualization and solving equations for my research immensely without having to pay the exorbitant amount of money for a comparable software. After familiarizing myself with creating meshes, and running different simulations (in my case mostly Navier-Stokes) I was attempting how to create a way to simulate the Brusselator equations and attempted to create two new terms that would model these equations. After following the very nice tutorial in the Developer's Guide, I mimicked all of the other term files and placed a file "terms_brussels.py" into the terms folder just as the other terms files are and I kept getting errors that there were no such terms as the ones I had made. I also attempted to (rather roguishly) append my new terms into a pre-existing term file. This could just be stupidity or naivety on my part, but how would one go about implimenting a new term that they had made. I have tried looking for more information in the documentation so I apologize if this question is covered there. Cheers, Gregory

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SfePy Application Doubt
by Pedro Henrique July 23, 2018

July 23, 2018

Good Morning, I'm a student at the State University of Ceará - Brazil. I wonder if Sfepy can be used to solve problems involving heat transfer in batch reactors? Att, *Pedro Henrique de Lima Gomes* ------------------------------------------------------------ Mestrando em Ciências Físicas Aplicadas - MACFA/UECE Engenheiro de Energias pela Universidade da Integração Internacional da Lusofonia Afro-Brasileira - UNILAB Contatos Lattes: http://lattes.cnpq.br/4633671274335176 E-mail: pedrodublebass(a)gmail.com Tel: (85) 997746629 -----------------------------------------------------------

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