SfePy December 2018

sfepy@python.org

3 participants
5 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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ANN: SfePy 2018.4
by Robert Cimrman 26 Dec '18

26 Dec '18

I am pleased to announce release 2018.4 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: https://mail.python.org/mm3/mailman3/lists/sfepy.python.org/ Git (source) repository, issue tracker: https://github.com/sfepy/sfepy Highlights of this release -------------------------- - better support for eigenvalue problems - improved MUMPS solver interface - support for logging and plotting of complex values For full release notes see [1]. Cheers, Robert Cimrman [1] http://docs.sfepy.org/doc/release_notes.html#id1 --- Contributors to this release in alphabetical order: Robert Cimrman Vladimir Lukes Matyas Novak Jan Heczko Lubos Kejzlar

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Problem with Sfepy building
by Francisco Ley 13 Dec '18

13 Dec '18

Hi, I just downloaded and tried to install Sfepy on my machine (I have Linux Mint, Anaconda, python 3.6) but there's a weird (and probably silly) error I'm getting when I tried to build the C modules. Before pasting the output of that I wonder if this email is the correct one to contact you for this type of errors in the installation. I've searched on the web for the error but I haven't found anything. I hope you can help me with this, I really look forward to start to use Sfepy. Thanks in advance, Francisco

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Number of quadrature points
by Jan Heczko 02 Dec '18

02 Dec '18

Hi, everyone! I am solving a planar problem using quad elements and the number of quadrature points bothers me a little. A minimal [interactive] working example would be like this: In [1]: from sfepy.discrete import Integral In [2]: i = Integral('i', 1) In [3]: i.get_qp('2_4') Out[3]: (array([[0.90824829, 0.5 ], [0.29587585, 0.85355339], [0.29587585, 0.14644661]]), array([0.33333333, 0.33333333, 0.33333333])) In [4]: i = Integral('i', 2) In [5]: i.get_qp('2_4') Out[5]: (array([[0.84156503, 0.5 ], [0.15843497, 0.5 ], [0.5 , 0.84156503], [0.5 , 0.15843497], [0.94095855, 0.94095855], [0.94095855, 0.05904145], [0.05904145, 0.94095855], [0.05904145, 0.05904145]]), array([0.20408163, 0.20408163, 0.20408163, 0.20408163, 0.04591837, 0.04591837, 0.04591837, 0.04591837])) In [6]: i = Integral('i', 3) In [7]: i.get_qp('2_4') Out[7]: (array([[0.21132487, 0.21132487], [0.78867513, 0.21132487], [0.21132487, 0.78867513], [0.78867513, 0.78867513]]), array([0.25, 0.25, 0.25, 0.25])) Why do I get 8 QPs for order 2 and 4 QPs for order 3? How does the order of the integral relate to the keys in `quadrature_tables` [1]? Best regards, Jan [1] http://sfepy.org/doc-devel/_modules/sfepy/discrete/quadratures.html

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SfePy December 2018