def QuadBallSurface(center=(0., 0., 0.), radius=1., n=10, element_type="quad"):
"""Creates a surface quad mesh on sphere using midpoint subdivision algorithm
by creating a cube and spherifying it using PostMesh's projection schemes.
Unlike the volume QuadBall method there is no restriction on number of divisions
here as no system of equations is solved
inputs:
n: [int] number of divsion in every direction.
Given that this implementation is based on
high order bases different divisions in
different directions is not possible
"""
try:
from Florence import Mesh, BoundaryCondition, DisplacementFormulation, FEMSolver, LinearSolver
from Florence import LinearElastic, NeoHookean
from Florence.Tensor import prime_number_factorisation
except ImportError:
raise ImportError("This function needs Florence's core support")
n = int(n)
if not isinstance(center, tuple):
raise ValueError(
"The center of the circle should be given in a tuple with two elements (x,y,z)"
)
if len(center) != 3:
raise ValueError(
"The center of the circle should be given in a tuple with two elements (x,y,z)"
)
if n == 2 or n == 3 or n == 5 or n == 7:
ps = [n]
else:
def factorise_all(n):
if n < 2:
n = 2
factors = prime_number_factorisation(n)
if len(factors) == 1 and n > 2:
n += 1
factors = prime_number_factorisation(n)
return factors
factors = factorise_all(n)
ps = []
for factor in factors:
ps += factorise_all(factor)
# Do high ps first
ps = np.sort(ps)[::-1].tolist()
niter = len(ps)
sphere_igs_file_content = SphereIGS()
with open("sphere_cad_file.igs", "w") as f:
f.write(sphere_igs_file_content)
sys.stdout = open(os.devnull, "w")
ndim = 3
scale = 1000.
condition = 1.e020
mesh = Mesh()
material = LinearElastic(ndim, mu=1., lamb=4.)
for it in range(niter):
if it == 0:
mesh.Parallelepiped(element_type="hex",
nx=1,
ny=1,
nz=1,
lower_left_rear_point=(-0.5, -0.5, -0.5),
upper_right_front_point=(0.5, 0.5, 0.5))
mesh = mesh.CreateSurface2DMeshfrom3DMesh()
mesh.GetHighOrderMesh(p=ps[it], equally_spaced=True)
mesh = mesh.CreateDummy3DMeshfrom2DMesh()
formulation = DisplacementFormulation(mesh)
else:
mesh.GetHighOrderMesh(p=ps[it], equally_spaced=True)
mesh = mesh.CreateDummy3DMeshfrom2DMesh()
boundary_condition = BoundaryCondition()
boundary_condition.SetCADProjectionParameters(
"sphere_cad_file.igs",
scale=scale,
condition=condition,
project_on_curves=True,
solve_for_planar_faces=True,
modify_linear_mesh_on_projection=True,
fix_dof_elsewhere=False)
boundary_condition.GetProjectionCriteria(mesh)
nodesDBC, Dirichlet = boundary_condition.PostMeshWrapper(
formulation, mesh, None, None, FEMSolver())
mesh.points[nodesDBC.ravel(), :] += Dirichlet
mesh = mesh.CreateSurface2DMeshfrom3DMesh()
mesh = mesh.ConvertToLinearMesh()
os.remove("sphere_cad_file.igs")
if not np.isclose(radius, 1):
mesh.points *= radius
mesh.points[:, 0] += center[0]
mesh.points[:, 1] += center[1]
mesh.points[:, 2] += center[2]
if element_type == "tri":
mesh.ConvertQuadsToTris()
sys.stdout = sys.__stdout__
return mesh
def QuadBall(center=(0., 0., 0.), radius=1., n=10, element_type="hex"):
"""Creates a fully hexahedral mesh on sphere using midpoint subdivision algorithm
by creating a cube and spherifying it using PostMesh's projection schemes
inputs:
n: [int] number of divsion in every direction.
Given that this implementation is based on
high order bases different divisions in
different directions is not possible
"""
try:
from Florence import Mesh, BoundaryCondition, DisplacementFormulation, FEMSolver, LinearSolver
from Florence import LinearElastic, NeoHookean
from Florence.Tensor import prime_number_factorisation
except ImportError:
raise ImportError("This function needs Florence's core support")
n = int(n)
if n > 50:
# Values beyond this result in >1M DoFs due to internal prime factoristaion splitting
raise ValueError(
"The value of n={} (division in each direction) is too high".
format(str(n)))
if not isinstance(center, tuple):
raise ValueError(
"The center of the circle should be given in a tuple with two elements (x,y,z)"
)
if len(center) != 3:
raise ValueError(
"The center of the circle should be given in a tuple with two elements (x,y,z)"
)
if n == 2 or n == 3 or n == 5 or n == 7:
ps = [n]
else:
def factorise_all(n):
if n < 2:
n = 2
factors = prime_number_factorisation(n)
if len(factors) == 1 and n > 2:
n += 1
factors = prime_number_factorisation(n)
return factors
factors = factorise_all(n)
ps = []
for factor in factors:
ps += factorise_all(factor)
# Do high ps first
ps = np.sort(ps)[::-1].tolist()
niter = len(ps)
# IGS file for sphere with radius 1000.
sphere_igs_file_content = SphereIGS()
with open("sphere_cad_file.igs", "w") as f:
f.write(sphere_igs_file_content)
sys.stdout = open(os.devnull, "w")
ndim = 3
scale = 1000.
condition = 1.e020
mesh = Mesh()
material = LinearElastic(ndim, mu=1., lamb=4.)
# Keep the solver iterative for low memory consumption. All boundary points are Dirichlet BCs
# so they will be exact anyway
solver = LinearSolver(linear_solver="iterative",
linear_solver_type="cg2",
dont_switch_solver=True,
iterative_solver_tolerance=1e-9)
for it in range(niter):
if it == 0:
mesh.Parallelepiped(element_type="hex",
nx=1,
ny=1,
nz=1,
lower_left_rear_point=(-0.5, -0.5, -0.5),
upper_right_front_point=(0.5, 0.5, 0.5))
mesh.GetHighOrderMesh(p=ps[it], equally_spaced=True)
boundary_condition = BoundaryCondition()
boundary_condition.SetCADProjectionParameters(
"sphere_cad_file.igs",
scale=scale,
condition=condition,
project_on_curves=True,
solve_for_planar_faces=True,
modify_linear_mesh_on_projection=True,
fix_dof_elsewhere=False)
boundary_condition.GetProjectionCriteria(mesh)
formulation = DisplacementFormulation(mesh)
fem_solver = FEMSolver(number_of_load_increments=1,
analysis_nature="linear",
force_not_computing_mesh_qualities=True,
report_log_level=0,
optimise=True)
solution = fem_solver.Solve(formulation=formulation,
mesh=mesh,
material=material,
boundary_condition=boundary_condition,
solver=solver)
mesh.points += solution.sol[:, :, -1]
mesh = mesh.ConvertToLinearMesh()
os.remove("sphere_cad_file.igs")
if not np.isclose(radius, 1):
mesh.points *= radius
mesh.points[:, 0] += center[0]
mesh.points[:, 1] += center[1]
mesh.points[:, 2] += center[2]
if element_type == "tet":
mesh.ConvertHexesToTets()
sys.stdout = sys.__stdout__
return mesh
