def create_forward_problem(
mesh,
activation,
active_value=0.0,
active_model="active_stain",
T_ref=1.0,
):
ffun = df.MeshFunction("size_t", mesh, 2)
ffun.set_all(0)
left = df.CompiledSubDomain("on_boundary && near(x[0], 0)")
left_marker = 1
left.mark(ffun, left_marker)
# Collect the functions containing the markers
marker_functions = pulse.MarkerFunctions(ffun=ffun)
def dirichlet_bc(W):
V = W if W.sub(0).num_sub_spaces() == 0 else W.sub(0)
return da.DirichletBC(V, da.Constant((0.0, 0.0, 0.0)), left)
bcs = pulse.BoundaryConditions(dirichlet=(dirichlet_bc, ), )
f0 = df.as_vector([1, 0, 0])
microstructure = pulse.Microstructure(f0=f0)
geometry = pulse.Geometry(
mesh=mesh,
marker_functions=marker_functions,
microstructure=microstructure,
)
material_parameters = dict(
a=2.28,
a_f=1.686,
b=9.726,
b_f=15.779,
a_s=0.0,
b_s=0.0,
a_fs=0.0,
b_fs=0.0,
)
material = pulse.HolzapfelOgden(
active_model=active_model,
parameters=material_parameters,
activation=activation,
T_ref=T_ref,
)
problem = pulse.MechanicsProblem(geometry, material, bcs)
problem.solve()
if active_value > 0.0:
pulse.iterate.iterate(problem, activation, active_value)
return problem
V_f = dolfin.VectorFunctionSpace(mesh, "CG", 1)
# Fibers
f0 = interpolate(Expression(("1.0", "0.0", "0.0"), degree=1), V_f)
# Sheets
s0 = interpolate(Expression(("0.0", "1.0", "0.0"), degree=1), V_f)
# Fiber-sheet normal
n0 = interpolate(Expression(("0.0", "0.0", "1.0"), degree=1), V_f)
# Collect the mictrotructure
microstructure = pulse.Microstructure(f0=f0, s0=s0, n0=n0)
# Create the geometry
geometry = pulse.Geometry(
mesh=mesh,
marker_functions=marker_functions,
microstructure=microstructure,
)
# Use the default material parameters
material_parameters = pulse.HolzapfelOgden.default_parameters()
# Select model for active contraction
active_model = pulse.ActiveModels.active_strain
# active_model = "active_stress"
# Set the activation
activation = Constant(0.0)
# Create material
material = pulse.HolzapfelOgden(
N = 4
mesh = UnitCubeMesh(N, N, N)
V_f = dolfin.VectorFunctionSpace(mesh, "CG", 1)
# Fibers
f0 = interpolate(Expression(("1.0", "0.0", "0.0"), degree=1), V_f)
# Sheets
s0 = interpolate(Expression(("0.0", "1.0", "0.0"), degree=1), V_f)
# Fiber-sheet normal
n0 = interpolate(Expression(("0.0", "0.0", "1.0"), degree=1), V_f)
microstructure = pulse.Microstructure(f0=f0, s0=s0, n0=n0)
# Create the geometry
geometry = pulse.Geometry(
mesh=mesh,
microstructure=microstructure,
)
# -
activation = Function(dolfin.FunctionSpace(geometry.mesh, "R", 0))
activation.assign(Constant(0.2))
matparams = pulse.HolzapfelOgden.default_parameters()
material = pulse.HolzapfelOgden(
activation=activation,
parameters=matparams,
f0=geometry.f0,
s0=geometry.s0,
n0=geometry.n0,
)
problem = RigidMotionProblem(geometry, material)