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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Python GetFEM interface
#
# Copyright (C) 2004-2020 Yves Renard, Julien Pommier.
#
# This file is a part of GetFEM
#
# GetFEM is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
# License for more details.
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
#
############################################################################
""" This is the "modern" tripod demo, which uses the getfem model bricks
importing the mesh.
This program is used to check that python-getfem is working. This is
also a good example of use of GetFEM.
$Id$
"""
import numpy as np
import getfem as gf
with_graphics=True
try:
import getfem_tvtk
except:
print("\n** Could NOT import getfem_tvtk -- graphical output disabled **\n")
import time
time.sleep(2)
with_graphics=False
m=gf.Mesh('import','gid','../meshes/tripod.GiD.msh')
print('done!')
mfu=gf.MeshFem(m,3) # displacement
mfp=gf.MeshFem(m,1) # pressure
mfd=gf.MeshFem(m,1) # data
mim=gf.MeshIm(m, gf.Integ('IM_TETRAHEDRON(5)'))
degree = 2
linear = False
incompressible = False # ensure that degree > 1 when incompressible is on..
mfu.set_fem(gf.Fem('FEM_PK(3,%d)' % (degree,)))
mfd.set_fem(gf.Fem('FEM_PK(3,0)'))
mfp.set_fem(gf.Fem('FEM_PK_DISCONTINUOUS(3,0)'))
print('nbcvs=%d, nbpts=%d, qdim=%d, fem = %s, nbdof=%d' % \
(m.nbcvs(), m.nbpts(), mfu.qdim(), mfu.fem()[0].char(), mfu.nbdof()))
P=m.pts()
print('test', P[1,:])
ctop=(abs(P[1,:] - 13) < 1e-6)
cbot=(abs(P[1,:] + 10) < 1e-6)
pidtop=np.compress(ctop, list(range(0, m.nbpts())))
pidbot=np.compress(cbot, list(range(0, m.nbpts())))
ftop=m.faces_from_pid(pidtop)
fbot=m.faces_from_pid(pidbot)
NEUMANN_BOUNDARY = 1
DIRICHLET_BOUNDARY = 2
m.set_region(NEUMANN_BOUNDARY,ftop)
m.set_region(DIRICHLET_BOUNDARY,fbot)
E=1e3
Nu=0.3
Lambda = E*Nu/((1+Nu)*(1-2*Nu))
Mu =E/(2*(1+Nu))
md = gf.Model('real')
md.add_fem_variable('u', mfu)
if linear:
md.add_initialized_data('cmu', Mu)
md.add_initialized_data('clambda', Lambda)
md.add_isotropic_linearized_elasticity_brick(mim, 'u', 'clambda', 'cmu')
if incompressible:
md.add_fem_variable('p', mfp)
md.add_linear_incompressibility_brick(mim, 'u', 'p')
else:
md.add_initialized_data('params', [Lambda, Mu]);
if incompressible:
lawname = 'Incompressible Mooney Rivlin';
md.add_finite_strain_elasticity_brick(mim, lawname, 'u', 'params')
md.add_fem_variable('p', mfp);
md.add_finite_strain_incompressibility_brick(mim, 'u', 'p');
else:
lawname = 'SaintVenant Kirchhoff';
md.add_finite_strain_elasticity_brick(mim, lawname, 'u', 'params');
md.add_initialized_data('VolumicData', [0,-1,0]);
md.add_source_term_brick(mim, 'u', 'VolumicData');
# Attach the tripod to the ground
md.add_Dirichlet_condition_with_multipliers(mim, 'u', mfu, 2);
print('running solve...')
md.solve('noisy', 'max iter', 1);
U = md.variable('u');
print('solve done!')
mfdu=gf.MeshFem(m,1)
mfdu.set_fem(gf.Fem('FEM_PK_DISCONTINUOUS(3,1)'))
if linear:
VM = md.compute_isotropic_linearized_Von_Mises_or_Tresca('u','clambda','cmu', mfdu);
else:
VM = md.compute_finite_strain_elasticity_Von_Mises(lawname, 'u', 'params', mfdu);
# post-processing
sl=gf.Slice(('boundary',), mfu, degree)
print('Von Mises range: ', VM.min(), VM.max())
# export results to VTK
sl.export_to_vtk('tripod.vtk', 'ascii', mfdu, VM, 'Von Mises Stress', mfu, U, 'Displacement')
sl.export_to_pos('tripod.pos', mfdu, VM, 'Von Mises Stress', mfu, U, 'Displacement')
gf.memstats()
print('You can view the tripod with (for example) mayavi:')
print('mayavi2 -d tripod.vtk -f WarpVector -m Surface')
print('or')
print('gmsh tripod.pos')
# mfu.save('tripod.mf', 'with_mesh')
# U.tofile('tripod.U')
# mfdu.save('tripod.mfe')
# VM.tofile('tripod.VM')
if with_graphics:
fig = getfem_tvtk.Figure()
fig.show(mfu, deformation=U, data=(mfdu,VM), deformation_scale='20%')
print("Press Q to continue..")
fig.set_colormap('tripod')
fig.loop()
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