SfePy July 2016

sfepy@python.org

3 participants
8 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 postproc.py
by Nikhil Vaidya 21 Jul '16

21 Jul '16

Hi I tried to solve the examples/diffusion/poisson_short_syntax.py using simple.py. The solution completes by when I try to visualize cylinder.vtk with postproc.py, I get the following error: Exception: In C:\Python27\lib\site-packages\mayavi\sources\vtk_xml_file_reader.py: 86 AttributeError: 'AlgorithmOutput' object has no attribute 'point_data' (in get_all_attributes) The above error is in a dialog box. when I click ok, the postproc window opens with no geometry shown. I have tried visualizing the vtk file in paraview and that shows a reasonabel t profile. Additionally, the error log is in the attached file. Please tell me how to solve this problem.

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Installation on windows using Visual C++ compiler
by Nikhil Vaidya 21 Jul '16

21 Jul '16

Hello, I downloaded the sfepy source code from git and installed it using the Visual C++ compiler. After installing, I ran the tests and 4 of them failed. I then ran those tests in debug mode and the output is attached. Please tell me how to solve this problem. Best regards, Nikhil

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Re: [sfepy-devel] Issue whith the variable coors
by Robert Cimrman 05 Jul '16

05 Jul '16

Hi Nicolas, you need only to return your values in 'qp' mode (and make them floats). It runs ok with those: def get_heat_Coeff(ts, coors, mode=None, **kwargs): if mode != 'qp': return file=open('heat_Coeff.dat', 'r') tab=[] tab=file.readlines() file.close() length=len(tab) for i in range(length): tab[i] = float(tab[i].strip()) val=nm.asarray(tab) val.shape = (coors.shape[0], 1, 1) return {'h' : val} def get_exchange(ts, coors, mode=None, **kwargs): if mode != 'qp': return file=open('exchange.dat', 'r') tab=[] tab=file.readlines() file.close() length=len(tab) for i in range(length): tab[i] = float(tab[i].strip()) val=nm.asarray(tab) val.shape = (coors.shape[0], 1, 1) return {'g' : val} BTW. make sure that the order of the values corresponds to the ordering of the quadrature point coordinates in coors argument. r. On 07/04/2016 03:27 PM, Nicolas DELAN wrote: > Hi, > > I have some problem with my case: > > I have followed your instructions and i was inspired by the get_pars > function of the following example case : > http://sfepy.org/doc-devel/examples/diffusion/poisson_functions.html > > But with me it don't works, the coors type returned is 'none' so the > coors.shape returned nothing. Stangely i have understand that the .py > configuration file is readed several time by sfepy, the first time coors is > recognised and i can print the coordinates. The second time, coors become a > none type variable and i don't understand why. > > Also could you take a look at my case ? > > I have attached my files to this post. > >

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Implementation of constant fields
by Nicolas DELAN 04 Jul '16

04 Jul '16

Hello, I have to formulate this equation in sfepy: <https://lh3.googleusercontent.com/--SRvfhvrVes/V3UtQhHns_I/AAAAAAAAVVI/URP8…> So with \partialOmega = gamma: """dw_laplace.i.Omega(c,s, t ) + dw_volume_dot.i.Gamma( h , t, s) =dw_surface_dot.i.Gamma(g, s )""" My question is: alpha and g are constants of the surface of the airfoil, i have two files that contains the values of them for each point of the surface (we are in a 2D problem). But i don't know how to define h and alpha in the configuration file as variables of the domain gamma with some ebcs conditions ?

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SfePy July 2016