params['material']['sigma_D0'])
params['geometry']['Ly'] = 1
fig1, ax1 = pp.plot_energy(params, data, tc)
# visuals.setspines2()
mu = params['material']['E'] / 2.
# elast_en = [1./2.*2.*mu*eps**2 for eps in data['load']]
elast_en = [
1. / 2. * params['material']['E'] * eps**2 for eps in data['load']
]
plt.plot(data['load'], elast_en, c='k')
ax1.axvline(pp.t_stab(ell), c='k', ls='-', lw=2, label='$t^{cr}_s$')
ax1.axvline(pp.t_bif(ell), c='k', ls='-.', lw=2, label=r'$t^{cr}_b$')
plt.title('${}$'.format(lab))
(fig2, ax1, ax2) = pp.plot_spectrum(params, data, tc)
ax1.axvline(pp.t_stab(ell), c='k', ls='-', lw=2, label='$t^{cr}_s$')
ax1.axvline(pp.t_bif(ell), c='k', ls='-.', lw=2, label=r'$t^{cr}_b$')
plt.plot(np.linspace(1, params['time_stepping']['load_max'], 30), [
1 - (t / params['material']['sigma_D0'] / params['material']['E'])
**(2 / (1 - 2))
for t in np.linspace(1, params['time_stepping']['load_max'], 30)
],
c='k',
lw=.5)
plt.title('${}$'.format(lab))
# visuals.setspines2()
ax1.set_ylim(-1., .2)
# fig1.savefig("/Users/kumiori/Documents/WIP/paper_stability/fig/energy-traction-{}.pdf".format(signature), bbox_inches='tight')
def traction_test(ell=0.05,
ell_e=.1,
degree=1,
n=3,
nu=0.,
load_min=0,
load_max=2,
loads=None,
nsteps=20,
Lx=1.,
Ly=0.1,
outdir="outdir",
postfix='',
savelag=1,
sigma_D0=1.,
periodic=False,
continuation=False,
checkstability=True,
configString='',
test=True):
# constants
# ell = ell
Lx = Lx
load_min = load_min
load_max = load_max
nsteps = nsteps
outdir = outdir
loads = loads
savelag = 1
nu = dolfin.Constant(nu)
ell = dolfin.Constant(ell)
ell_e = ell_e
E = dolfin.Constant(1.0)
K = E.values()[0] / ell_e**2.
sigma_D0 = E
n = n
# h = ell.values()[0]/n
h = max(ell.values()[0] / n, .005)
cell_size = h
continuation = continuation
isPeriodic = periodic
config = json.loads(configString) if configString != '' else ''
cmd_parameters = {
'material': {
"ell": ell.values()[0],
"ell_e": ell_e,
"K": K,
"E": E.values()[0],
"nu": nu.values()[0],
"sigma_D0": sigma_D0.values()[0]
},
'geometry': {
'Lx': Lx,
'Ly': Ly,
'n': n,
},
'experiment': {
'test': test,
'periodic': isPeriodic,
'signature': ''
},
'stability': {
'checkstability': checkstability,
'continuation': continuation
},
'time_stepping': {
'load_min': load_min,
'load_max': load_max,
'nsteps': nsteps,
'outdir': outdir,
'postfix': postfix,
'savelag': savelag
},
'alt_min': {},
"code": {}
}
# --------------------
for par in parameters:
parameters[par].update(cmd_parameters[par])
if config:
for par in config:
parameters[par].update(config[par])
# else:
# parameters['material']['ell_e'] =
Lx = parameters['geometry']['Lx']
Ly = parameters['geometry']['Ly']
ell = parameters['material']['ell']
ell_e = parameters['material']['ell_e']
BASE_DIR = os.path.dirname(os.path.realpath(__file__))
fname = "film"
print(BASE_DIR)
os.path.isfile(fname)
signature = hashlib.md5(str(parameters).encode('utf-8')).hexdigest()
if parameters['experiment']['test'] == True:
outdir += '-{}'.format(cmd_parameters['time_stepping']['postfix'])
else:
outdir += '-{}{}'.format(signature,
cmd_parameters['time_stepping']['postfix'])
outdir = outdir + '-cont'
parameters['time_stepping']['outdir'] = outdir
Path(outdir).mkdir(parents=True, exist_ok=True)
print('Outdir is: ' + outdir)
with open(os.path.join(outdir, 'rerun.sh'), 'w') as f:
configuration = deepcopy(parameters)
configuration['time_stepping'].pop('outdir')
str(configuration).replace("\'True\'",
"True").replace("\'False\'", "False")
rerun_cmd = 'python3 {} --config="{}"'.format(
os.path.basename(__file__), configuration)
f.write(rerun_cmd)
with open(os.path.join(outdir, 'parameters.pkl'), 'w') as f:
json.dump(parameters, f)
with open(os.path.join(outdir, 'signature.md5'), 'w') as f:
f.write(signature)
print(parameters)
# boundary_meshfunction = dolfin.MeshFunction("size_t", mesh, "meshes/%s-%s_facet_region.xml"%(fname, signature))
# cells_meshfunction = dolfin.MeshFunction("size_t", mesh, "meshes/%s-%s_physical_region.xml"%(fname, signature))
# ------------------
geometry_parameters = parameters['geometry']
geom_signature = hashlib.md5(
str(geometry_parameters).encode('utf-8')).hexdigest()
meshfile = "%s/meshes/%s-%s.xml" % (BASE_DIR, fname, geom_signature)
# cmd_parameters['experiment']['signature']=signature
if os.path.isfile(meshfile):
print("Meshfile %s exists" % meshfile)
mesh = dolfin.Mesh("meshes/%s-%s.xml" % (fname, geom_signature))
else:
print("Creating meshfile: %s" % meshfile)
print(('DEBUG: (-Lx/2. ={} , -Ly/2.={})'.format(Lx / 2., -Ly / 2.)))
geom = mshr.Rectangle(dolfin.Point(-Lx / 2., -Ly / 2.),
dolfin.Point(Lx / 2., Ly / 2.))
mesh = mshr.generate_mesh(geom, n * int(float(Lx / ell)))
print(meshfile)
mesh_xdmf = dolfin.XDMFFile("meshes/%s-%s.xdmf" % (fname, geom_signature))
mesh_xdmf.write(mesh)
if rank == 0:
meshf = dolfin.File(os.path.join(outdir, "mesh.xml"))
meshf << mesh
V_u = dolfin.VectorFunctionSpace(mesh, "CG", 1)
V_alpha = dolfin.FunctionSpace(mesh, "CG", 1)
u = dolfin.Function(V_u, name="Total displacement")
alpha = dolfin.Function(V_alpha, name="Damage")
bcs_alpha = []
bcs_u = [
DirichletBC(V_u, Constant((0., 0)),
'(near(x[0], %f) or near(x[0], %f))' % (-Lx / 2., Lx / 2.))
]
left = dolfin.CompiledSubDomain("near(x[0], -Lx/2.)", Lx=Lx)
right = dolfin.CompiledSubDomain("near(x[0], Lx/2.)", Lx=Lx)
bottom = dolfin.CompiledSubDomain("near(x[1],-Ly/2.)", Ly=Ly)
top = dolfin.CompiledSubDomain("near(x[1],Ly/2.)", Ly=Ly)
mf = dolfin.MeshFunction("size_t", mesh, 1, 0)
right.mark(mf, 1)
left.mark(mf, 2)
bottom.mark(mf, 3)
state = [u, alpha]
Z = dolfin.FunctionSpace(
mesh, dolfin.MixedElement([u.ufl_element(),
alpha.ufl_element()]))
z = dolfin.Function(Z)
v, beta = dolfin.split(z)
dx = dolfin.Measure("dx", metadata=form_compiler_parameters, domain=mesh)
ds = dolfin.Measure("ds", subdomain_data=mf)
# Files for output
file_out = dolfin.XDMFFile(os.path.join(outdir, "output.xdmf"))
file_eig = dolfin.XDMFFile(os.path.join(outdir, "perturbations.xdmf"))
file_con = dolfin.XDMFFile(os.path.join(outdir, "continuation.xdmf"))
file_bif = dolfin.XDMFFile(
os.path.join(outdir, "bifurcation_postproc.xdmf"))
for f in [file_out, file_eig, file_con, file_bif]:
f.parameters["functions_share_mesh"] = True
f.parameters["flush_output"] = True
# Problem definition
foundation_density = 1. / 2. * 1. / ell_e**2. * dot(u, u)
model = DamagePrestrainedElasticityModel(
state,
E,
nu,
ell,
sigma_D0,
user_functional=foundation_density,
eps0t=Expression([['t', 0.], [0., 0.]], t=0., degree=0))
# import pdb; .set_trace()
model.dx = dx
model.ds = ds
energy = model.total_energy_density(u, alpha) * dx
# Alternate minimization solver
solver = solvers.AlternateMinimizationSolver(
energy, [u, alpha], [bcs_u, bcs_alpha],
parameters=parameters['alt_min'])
rP = model.rP(u, alpha, v, beta) * dx + 1 / ell_e**2. * dot(v, v) * dx
rN = model.rN(u, alpha, beta) * dx
stability = StabilitySolver(mesh,
energy, [u, alpha], [bcs_u, bcs_alpha],
z,
parameters=parameters['stability'])
# stability = StabilitySolver(mesh, energy, [u, alpha], [bcs_u, bcs_alpha], z, parameters = parameters['stability'], rayleigh=[rP, rN])
# if isPeriodic:
# stability = StabilitySolver(mesh, energy, [u, alpha], [bcs_u, bcs_alpha], z,
# parameters = stability_parameters,
# constrained_domain = PeriodicBoundary(Lx))
# else:
# stability = StabilitySolver(mesh, energy, [u, alpha], [bcs_u, bcs_alpha], z, parameters = parameters['stability'])
load_steps = np.linspace(load_min, load_max,
parameters['time_stepping']['nsteps'])
if loads:
load_steps = loads
time_data = []
linesearch = LineSearch(energy, [u, alpha])
alpha_old = dolfin.Function(alpha.function_space())
lmbda_min_prev = 0.000001
bifurcated = False
bifurcation_loads = []
save_current_bifurcation = False
bifurc_count = 0
alpha_bif = dolfin.Function(V_alpha)
alpha_bif_old = dolfin.Function(V_alpha)
bifurcation_loads = []
tot_energy = model.elastic_energy_density(model.eps(u), alpha)*dx + \
1./2.*1/ell_e**2. * dot(u, u)*dx + \
model.damage_dissipation_density(alpha)*dx
cont_atol = 1e-3
for it, load in enumerate(load_steps):
model.eps0t.t = load
alpha_old.assign(alpha)
ColorPrint.print_warn('Solving load t = {:.2f}'.format(load))
# First order stability conditions
(time_data_i, am_iter) = solver.solve()
# Second order stability conditions
(stable, negev) = stability.solve(solver.problem_alpha.lb)
ColorPrint.print_pass(
'Current state is{}stable'.format(' ' if stable else ' un'))
# import pdb; pdb.set_trace()
mineig = stability.mineig if hasattr(stability, 'mineig') else 0.0
# print('DEBUG: lmbda min', lmbda_min_prev)
# print('DEBUG: mineig', mineig)
Deltav = (mineig - lmbda_min_prev) if hasattr(stability, 'eigs') else 0
if (mineig + Deltav) * (lmbda_min_prev +
dolfin.DOLFIN_EPS) < 0 and not bifurcated:
bifurcated = True
# save 3 bif modes
print('DEBUG: About to bifurcate load ', load, 'step', it)
bifurcation_loads.append(load)
bifurc_count += 1
lmbda_min_prev = mineig if hasattr(stability, 'mineig') else 0.
if stable:
solver.update()
else:
# Continuation
iteration = 1
energy_pre = dolfin.assemble(tot_energy)
alpha_bif.assign(alpha)
alpha_bif_old.assign(alpha_old)
while stable == False and iteration < 30:
# linesearch
perturbation_v = stability.perturbation_v
perturbation_beta = stability.perturbation_beta
h_opt, (hmin, hmax), energy_perturbations = linesearch.search(
[u, alpha, alpha_old], perturbation_v, perturbation_beta)
# import pdb; pdb.set_trace()
# if h_opt != 0:
if h_opt > cont_atol:
save_current_bifurcation = True
# admissible
uval = u.vector()[:] + h_opt * perturbation_v.vector()[:]
aval = alpha.vector(
)[:] + h_opt * perturbation_beta.vector()[:]
u.vector()[:] = uval
alpha.vector()[:] = aval
u.vector().vec().ghostUpdate()
alpha.vector().vec().ghostUpdate()
(time_data_i, am_iter) = solver.solve()
(stable, negev) = stability.solve(alpha_old)
ColorPrint.print_pass(
' Continuation iteration #{}, current state is{}stable'
.format(iteration, ' ' if stable else ' un'))
energy_post = dolfin.assemble(tot_energy)
ener_diff = energy_post - energy_pre
ColorPrint.print_warn(
'DEBUG: step {}, iteration {}, En_post - En_pre ={}'.
format(it, iteration, energy_post - energy_pre))
iteration += 1
if ener_diff < 0: bifurcated = False
else:
# warn
ColorPrint.print_warn(
'DEBUG: Found (almost) zero increment, we are stuck in the matrix'
)
ColorPrint.print_warn('DEBUG: h_opt = {}'.format(h_opt))
ColorPrint.print_warn('DEBUG: Continuing load program')
break
solver.update()
# stable == True
# modes = np.where(stability.eigs < 0)[0]
# with file_bif as file:
# leneigs = len(modes)
# maxmodes = min(3, leneigs)
# for n in range(maxmodes):
# mode = dolfin.project(stability.linsearch[n]['beta_n'], V_alpha)
# modename = 'beta-%d'%n
# print(modename)
# file.write_checkpoint(mode, modename, 0, append=True)
# bifurc_count += 1
time_data_i["load"] = load
time_data_i["stable"] = stable
time_data_i["dissipated_energy"] = dolfin.assemble(
model.damage_dissipation_density(alpha) * dx)
time_data_i["foundation_energy"] = dolfin.assemble(
1. / 2. * 1 / ell_e**2. * dot(u, u) * dx)
time_data_i["membrane_energy"] = dolfin.assemble(
model.elastic_energy_density(model.eps(u), alpha) * dx)
time_data_i["elastic_energy"] = time_data_i[
"membrane_energy"] + time_data_i["foundation_energy"]
time_data_i["eigs"] = stability.eigs if hasattr(stability,
'eigs') else np.inf
time_data_i["stable"] = stability.stable
time_data_i["# neg ev"] = stability.negev
# import pdb; pdb.set_trace()
_sigma = model.stress(model.eps(u), alpha)
e1 = dolfin.Constant([1, 0])
_snn = dolfin.dot(dolfin.dot(_sigma, e1), e1)
time_data_i["sigma"] = 1 / Ly * dolfin.assemble(_snn * model.ds(1))
time_data_i["S(alpha)"] = dolfin.assemble(1. / (model.a(alpha)) *
model.dx)
time_data_i["A(alpha)"] = dolfin.assemble((model.a(alpha)) * model.dx)
time_data_i["avg_alpha"] = dolfin.assemble(alpha * model.dx)
ColorPrint.print_pass(
"Time step {:.4g}: it {:3d}, err_alpha={:.4g}".format(
time_data_i["load"], time_data_i["iterations"],
time_data_i["alpha_error"]))
time_data.append(time_data_i)
time_data_pd = pd.DataFrame(time_data)
if np.mod(it, savelag) == 0:
with file_out as f:
f.write(alpha, load)
f.write(u, load)
f.write_checkpoint(alpha,
"alpha-{}".format(it),
0,
append=True)
# with file_bif as f:
print('DEBUG: written step ', it)
if save_current_bifurcation:
# modes = np.where(stability.eigs < 0)[0]
time_data_i['h_opt'] = h_opt
time_data_i['max_h'] = hmax
time_data_i['min_h'] = hmin
with file_bif as file:
beta0v = dolfin.project(stability.perturbation_beta, V_alpha)
file.write_checkpoint(beta0v,
'beta0',
bifurc_count - 1,
append=True)
file.write_checkpoint(alpha_bif_old,
'alpha-old',
bifurc_count - 1,
append=True)
file.write_checkpoint(alpha_bif,
'alpha-bif',
bifurc_count - 1,
append=True)
file.write_checkpoint(alpha,
'alpha',
bifurc_count - 1,
append=True)
np.save(os.path.join(outdir, 'energy_perturbations'),
energy_perturbations,
allow_pickle=True,
fix_imports=True)
with file_eig as file:
_v = dolfin.project(
dolfin.Constant(h_opt) * perturbation_v, V_u)
_beta = dolfin.project(
dolfin.Constant(h_opt) * perturbation_beta, V_alpha)
_v.rename('perturbation displacement',
'perturbation displacement')
_beta.rename('perturbation damage', 'perturbation damage')
# import pdb; pdb.set_trace()
f.write(_v, load)
f.write(_beta, load)
file.write_checkpoint(_v,
'perturbation_v',
bifurc_count - 1,
append=True)
file.write_checkpoint(_beta,
'perturbation_beta',
bifurc_count - 1,
append=True)
save_current_bifurcation = False
time_data_pd.to_json(os.path.join(outdir, "time_data.json"))
plt.figure()
plt.plot(time_data_pd["load"].values(),
time_data_pd["iterations"].values(),
label='its')
plt.semilogy()
ax = plt.gca()
ax2 = ax.twinx()
ax2.plot(time_data_pd["load"].values(),
time_data_pd["alpha_error"].values(),
'o',
c='C1',
label='alpha error')
plt.savefig(os.path.join(outdir, 'am.pdf'))
plt.legend()
plt.close()
# user_postprocess_timestep(alpha, parameters, load, xresol = 100)
plt.figure()
dolfin.plot(alpha)
plt.savefig(os.path.join(outdir, "alpha.png"))
plt.figure()
dolfin.plot(u, mode="displacement")
plt.savefig(os.path.join(outdir, "u.png"))
_nu = parameters['material']['nu']
_E = parameters['material']['E']
_w1 = parameters['material']['sigma_D0']**2. / parameters['material']['E']
tc = np.sqrt(2 * _w1 / (_E * (1. - 2. * _nu) * (1. + _nu)))
if parameters['stability']['checkstability'] == 'True':
pp.plot_spectrum(parameters, outdir, time_data_pd.sort_values('load'),
tc)
# plt.show()
print(time_data_pd)
print()
print('Output in: ' + outdir)
return time_data_pd
def traction_test(ell=0.05,
ell_e=.1,
degree=1,
n=3,
nu=0.,
load_min=0,
load_max=2,
loads=None,
nsteps=20,
Lx=1.,
Ly=0.1,
outdir="outdir",
postfix='',
savelag=1,
sigma_D0=1.,
periodic=False,
continuation=False,
checkstability=True,
configString='',
test=True):
# constants
# ell = ell
Lx = Lx
load_min = load_min
load_max = load_max
nsteps = nsteps
outdir = outdir
loads = loads
savelag = 1
nu = dolfin.Constant(nu)
ell = dolfin.Constant(ell)
ell_e = ell_e
E = dolfin.Constant(1.0)
K = E.values()[0] / ell_e**2.
sigma_D0 = E
n = n
# h = ell.values()[0]/n
h = max(ell.values()[0] / n, .005)
cell_size = h
continuation = continuation
isPeriodic = periodic
config = json.loads(configString) if configString != '' else ''
cmd_parameters = {
'material': {
"ell": ell.values()[0],
"ell_e": ell_e,
"K": K,
"E": E.values()[0],
"nu": nu.values()[0],
"sigma_D0": sigma_D0.values()[0]
},
'geometry': {
'Lx': Lx,
'Ly': Ly,
'n': n,
},
'experiment': {
'periodic': isPeriodic,
'signature': ''
},
'stability': {
'checkstability': checkstability,
'continuation': continuation
},
'time_stepping': {
'load_min': load_min,
'load_max': load_max,
'nsteps': nsteps,
'outdir': outdir,
'postfix': postfix,
'savelag': savelag
},
'alt_min': {},
"code": {}
}
# --------------------
for par in parameters:
parameters[par].update(cmd_parameters[par])
if config:
# import pdb; pdb.set_trace()
for par in config:
parameters[par].update(config[par])
# else:
# parameters['material']['ell_e'] =
# import pdb; pdb.set_trace()
Lx = parameters['geometry']['Lx']
Ly = parameters['geometry']['Ly']
ell = parameters['material']['ell']
ell_e = parameters['material']['ell_e']
BASE_DIR = os.path.dirname(os.path.realpath(__file__))
fname = "film"
print(BASE_DIR)
os.path.isfile(fname)
signature = hashlib.md5(str(parameters).encode('utf-8')).hexdigest()
print('Signature is: ' + signature)
# if parameters['experiment']['test'] == True: outdir += '-{}'.format(cmd_parameters['time_stepping']['postfix'])
# else:
outdir += '-{}{}'.format(signature,
cmd_parameters['time_stepping']['postfix'])
parameters['time_stepping']['outdir'] = outdir
Path(outdir).mkdir(parents=True, exist_ok=True)
print('Outdir is: ' + outdir)
with open(os.path.join(outdir, 'rerun.sh'), 'w') as f:
configuration = deepcopy(parameters)
configuration['time_stepping'].pop('outdir')
str(configuration).replace("\'True\'",
"True").replace("\'False\'", "False")
rerun_cmd = 'python3 {} --config="{}"'.format(
os.path.basename(__file__), configuration)
f.write(rerun_cmd)
with open(os.path.join(outdir, 'parameters.pkl'), 'w') as f:
json.dump(parameters, f)
with open(os.path.join(outdir, 'signature.md5'), 'w') as f:
f.write(signature)
print(parameters)
# ------------------
geometry_parameters = parameters['geometry']
geom_signature = hashlib.md5(
str(geometry_parameters).encode('utf-8')).hexdigest()
meshfile = "%s/meshes/circle-%s.xml" % (BASE_DIR, geom_signature)
# cmd_parameters['experiment']['signature']=signature
meshsize = parameters['material']['ell'] / parameters['geometry']['n']
d = {
'rad': parameters['geometry']['Lx'],
'Ly': parameters['geometry']['Ly'],
'meshsize': meshsize
}
if os.path.isfile(meshfile):
print("Meshfile %s exists" % meshfile)
mesh = dolfin.Mesh("meshes/circle-%s.xml" % (geom_signature))
else:
print("Creating meshfile: %s" % meshfile)
print("DEBUG: parameters: %s" % parameters['geometry'])
mesh_template = open('templates/circle_template.geo')
src = Template(mesh_template.read())
geofile = src.substitute(d)
if MPI.rank(MPI.comm_world) == 0:
with open("meshes/circle-%s" % geom_signature + ".geo", 'w') as f:
f.write(geofile)
cmd1 = 'gmsh meshes/circle-{}.geo -2 -o meshes/circle-{}.msh'.format(
geom_signature, geom_signature)
cmd2 = 'dolfin-convert -i gmsh meshes/circle-{}.msh meshes/circle-{}.xml'.format(
geom_signature, geom_signature)
print(
'Unable to handle mesh generation at the moment, please generate the mesh and test again.'
)
print(cmd1)
print(cmd2)
sys.exit()
print(check_output([cmd1], shell=True)
) # run in shell mode in case you are not run in terminal
Popen([cmd2], stdout=PIPE, shell=True).communicate()
mesh = Mesh('meshes/circle-{}.xml'.format(geom_signature))
mesh_xdmf = XDMFFile("meshes/circle-%s.xdmf" % (geom_signature))
mesh_xdmf.write(mesh)
# with pygmsh.geo.Geometry() as geom:
# circle = geom.add_circle(
# [0.0, 0.0, 0.0],
# 1.0,
# mesh_size=0.1,
# num_sections=4,
# # If compound==False, the section borders have to be points of the
# # discretization. If using a compound circle, they don't; gmsh can
# # choose by itself where to point the circle points.
# compound=True,
# )
# geom.add_physical(circle.plane_surface, "disk")
# #
# mesh = geom.generate_mesh()
# mesh.write("out.xdmf")
# mesh.write("out.xml")
# geom = mshr.Rectangle(dolfin.Point(-Lx/2., -Ly/2.), dolfin.Point(Lx/2., Ly/2.))
# mesh = mshr.generate_mesh(geom, n * int(float(Lx / ell)))
print(meshfile)
mesh_xdmf = dolfin.XDMFFile("meshes/%s-%s.xdmf" % (fname, geom_signature))
mesh_xdmf.write(mesh)
if rank == 0:
meshf = dolfin.File(os.path.join(outdir, "mesh.xml"))
meshf << mesh
V_u = dolfin.VectorFunctionSpace(mesh, "CG", 1)
V_alpha = dolfin.FunctionSpace(mesh, "CG", 1)
u = dolfin.Function(V_u, name="Total displacement")
alpha = dolfin.Function(V_alpha, name="Damage")
bcs_alpha = []
# Rectangle
# bcs_u = [DirichletBC(V_u, Constant((0., 0)), '(near(x[0], %f) or near(x[0], %f))'%(-Lx/2., Lx/2.))]
# Circle
bcs_u = [DirichletBC(V_u, Constant((0., 0.)), 'on_boundary')]
state = [u, alpha]
Z = dolfin.FunctionSpace(
mesh, dolfin.MixedElement([u.ufl_element(),
alpha.ufl_element()]))
z = dolfin.Function(Z)
v, beta = dolfin.split(z)
dx = dolfin.Measure("dx", metadata=form_compiler_parameters, domain=mesh)
ds = dolfin.Measure("ds")
# Files for output
file_out = dolfin.XDMFFile(os.path.join(outdir, "output.xdmf"))
file_eig = dolfin.XDMFFile(os.path.join(outdir, "perturbations.xdmf"))
file_con = dolfin.XDMFFile(os.path.join(outdir, "continuation.xdmf"))
file_bif = dolfin.XDMFFile(
os.path.join(outdir, "bifurcation_postproc.xdmf"))
for f in [file_out, file_eig, file_con, file_bif]:
f.parameters["functions_share_mesh"] = True
f.parameters["flush_output"] = True
# Problem
foundation_density = 1. / 2. * 1. / ell_e**2. * dot(u, u)
model = DamagePrestrainedElasticityModel(
state,
E,
nu,
ell,
sigma_D0,
user_functional=foundation_density,
eps0t=Expression([['t', 0.], [0., 't']], t=0., degree=0))
# import pdb; pdb.set_trace()
model.dx = dx
model.ds = ds
energy = model.total_energy_density(u, alpha) * dx
# Alternate minimization solver
solver = solvers.AlternateMinimizationSolver(
energy, [u, alpha], [bcs_u, bcs_alpha],
parameters=parameters['alt_min'])
rP = model.rP(u, alpha, v, beta) * dx + 1 / ell_e**2. * dot(v, v) * dx
rN = model.rN(u, alpha, beta) * dx
# stability = StabilitySolver(mesh, energy, [u, alpha], [bcs_u, bcs_alpha], z, parameters = parameters['stability'])
stability = StabilitySolver(mesh,
energy, [u, alpha], [bcs_u, bcs_alpha],
z,
parameters=parameters['stability'],
rayleigh=[rP, rN])
load_steps = np.linspace(load_min, load_max,
parameters['time_stepping']['nsteps'])
if loads:
load_steps = loads
time_data = []
linesearch = LineSearch(energy, [u, alpha])
alpha_old = dolfin.Function(alpha.function_space())
lmbda_min_prev = 0.000001
bifurcated = False
bifurcation_loads = []
save_current_bifurcation = False
bifurc_i = 0
alpha_bif = dolfin.Function(V_alpha)
alpha_bif_old = dolfin.Function(V_alpha)
for it, load in enumerate(load_steps):
model.eps0t.t = load
alpha_old.assign(alpha)
ColorPrint.print_warn('Solving load t = {:.2f}'.format(load))
# First order stability conditions
(time_data_i, am_iter) = solver.solve()
# Second order stability conditions
(stable, negev) = stability.solve(solver.problem_alpha.lb)
ColorPrint.print_pass(
'Current state is{}stable'.format(' ' if stable else ' un'))
mineig = stability.mineig if hasattr(stability, 'mineig') else 0.0
print('lmbda min', lmbda_min_prev)
print('mineig', mineig)
Deltav = (mineig - lmbda_min_prev) if hasattr(stability, 'eigs') else 0
if (mineig + Deltav) * (lmbda_min_prev +
dolfin.DOLFIN_EPS) < 0 and not bifurcated:
bifurcated = True
# save 3 bif modes
print('About to bifurcate load ', load, 'step', it)
bifurcation_loads.append(load)
print('DEBUG: decide what to do')
# save_current_bifurcation = True
bifurc_i += 1
lmbda_min_prev = mineig if hasattr(stability, 'mineig') else 0.
if stable:
solver.update()
else:
# Continuation
iteration = 1
while stable == False:
# linesearch
perturbation_v = stability.perturbation_v
perturbation_beta = stability.perturbation_beta
h_opt, (hmin, hmax), energy_perturbations = linesearch.search(
[u, alpha, alpha_old], perturbation_v, perturbation_beta)
if h_opt != 0:
save_current_bifurcation = True
alpha_bif.assign(alpha)
alpha_bif_old.assign(alpha_old)
# admissible
uval = u.vector()[:] + h_opt * perturbation_v.vector()[:]
aval = alpha.vector(
)[:] + h_opt * perturbation_beta.vector()[:]
u.vector()[:] = uval
alpha.vector()[:] = aval
u.vector().vec().ghostUpdate()
alpha.vector().vec().ghostUpdate()
# import pdb; pdb.set_trace()
(time_data_i, am_iter) = solver.solve()
(stable, negev) = stability.solve(alpha_old)
ColorPrint.print_pass(
' Continuation iteration {}, current state is{}stable'
.format(iteration, ' ' if stable else ' un'))
iteration += 1
else:
# warn
ColorPrint.print_warn(
'Found zero increment, we are stuck in the matrix')
ColorPrint.print_warn('Continuing load program')
break
solver.update()
# stable == True
time_data_i["load"] = load
time_data_i["stable"] = stable
time_data_i["dissipated_energy"] = dolfin.assemble(
model.damage_dissipation_density(alpha) * dx)
time_data_i["foundation_energy"] = dolfin.assemble(
1. / 2. * 1 / ell_e**2. * dot(u, u) * dx)
time_data_i["membrane_energy"] = dolfin.assemble(
model.elastic_energy_density(model.eps(u), alpha) * dx)
time_data_i["elastic_energy"] = time_data_i[
"membrane_energy"] + time_data_i["foundation_energy"]
time_data_i["eigs"] = stability.eigs if hasattr(stability,
'eigs') else np.inf
time_data_i["stable"] = stability.stable
time_data_i["# neg ev"] = stability.negev
_sigma = model.stress(model.eps(u), alpha)
e1 = dolfin.Constant([1, 0])
_snn = dolfin.dot(dolfin.dot(_sigma, e1), e1)
time_data_i["sigma"] = 1 / Ly * dolfin.assemble(_snn * model.ds(1))
time_data_i["S(alpha)"] = dolfin.assemble(1. / (model.a(alpha)) *
model.dx)
time_data_i["A(alpha)"] = dolfin.assemble((model.a(alpha)) * model.dx)
time_data_i["avg_alpha"] = 1 / dolfin.assemble(
dolfin.project(Constant(1.), V_alpha) *
model.dx) * dolfin.assemble(alpha * model.dx)
ColorPrint.print_pass(
"Time step {:.4g}: it {:3d}, err_alpha={:.4g}".format(
time_data_i["load"], time_data_i["iterations"],
time_data_i["alpha_error"]))
time_data.append(time_data_i)
time_data_pd = pd.DataFrame(time_data)
if np.mod(it, savelag) == 0:
with file_out as f:
f.write(alpha, load)
f.write(u, load)
# with file_out as f:
f.write_checkpoint(alpha,
"alpha-{}".format(it),
0,
append=True)
print('DEBUG: written step ', it)
if save_current_bifurcation:
# modes = np.where(stability.eigs < 0)[0]
time_data_i['h_opt'] = h_opt
time_data_i['max_h'] = hmax
time_data_i['min_h'] = hmin
with file_bif as file:
# leneigs = len(modes)
# maxmodes = min(3, leneigs)
beta0v = dolfin.project(stability.perturbation_beta, V_alpha)
print('DEBUG: irrev ', alpha.vector() - alpha_old.vector())
file.write_checkpoint(beta0v, 'beta0', 0, append=True)
file.write_checkpoint(alpha_bif_old,
'alpha-old',
0,
append=True)
file.write_checkpoint(alpha_bif, 'alpha-bif', 0, append=True)
file.write_checkpoint(alpha, 'alpha', 0, append=True)
np.save(os.path.join(outdir, 'energy_perturbations'),
energy_perturbations,
allow_pickle=True,
fix_imports=True)
with file_eig as file:
_v = dolfin.project(
dolfin.Constant(h_opt) * perturbation_v, V_u)
_beta = dolfin.project(
dolfin.Constant(h_opt) * perturbation_beta, V_alpha)
_v.rename('perturbation displacement',
'perturbation displacement')
_beta.rename('perturbation damage', 'perturbation damage')
# import pdb; pdb.set_trace()
f.write(_v, load)
f.write(_beta, load)
file.write_checkpoint(_v, 'perturbation_v', 0, append=True)
file.write_checkpoint(_beta,
'perturbation_beta',
0,
append=True)
time_data_pd.to_json(os.path.join(outdir, "time_data.json"))
# user_postprocess_timestep(alpha, parameters, load, xresol = 100)
plt.figure()
dolfin.plot(alpha)
plt.savefig(os.path.join(outdir, "alpha.png"))
plt.figure()
dolfin.plot(u, mode="displacement")
plt.savefig(os.path.join(outdir, "u.png"))
_nu = parameters['material']['nu']
_E = parameters['material']['E']
_w1 = parameters['material']['sigma_D0']**2. / parameters['material']['E']
tc = np.sqrt(2 * _w1 / (_E * (1. - 2. * _nu) * (1. + _nu)))
if parameters['stability']['checkstability'] == 'True':
pp.plot_spectrum(parameters, outdir, time_data_pd.sort_values('load'),
tc)
# plt.show()
collect_timings(outdir, t0)
print(time_data_pd)
return time_data_pd