from os import replace
from numpy import pi
from ...Classes.Arc import Arc
import sys
import gmsh
from os.path import splitext
[docs]def gen_3D_mesh(
lamination,
save_path="Lamination.msh",
sym=-1,
mesh_size=5e-3,
user_mesh_dict=None,
is_rect=False,
Nlayer=20,
display=True,
):
"""Draw 3D mesh of the lamination
Parameters
----------
lamination: LamSlot
Lamintation with slot to draw
save_path: str
Path to save the msh result file
sym : int
Number of symmetry to apply
mesh_size : float
Size of the mesh [m]
user_mesh_dict : dict
To enforce the number of elements on the lines
is_rect : bool
To use rectangular elements
Nlayer : int
Number of mesh layer on Z axis
display : bool
To display gmsh logs
Returns
-------
None
"""
# The defaut symmetry is Zs => We draw only one tooth
if sym == -1:
tooth_surf = lamination.slot.get_surface_tooth()
Zs = lamination.get_Zs()
else:
tooth_surf = lamination.build_geometry(sym=sym)[0]
Zs = sym
# For readibility
model = gmsh.model
factory = model.geo
L = lamination.L1 # Lamination length
# Start a new model
gmsh.initialize()
gmsh.option.setNumber("General.Terminal", int(display))
gmsh.option.setNumber("Geometry.CopyMeshingMethod", 1)
model.add("Pyleecan")
# Create all the points of the tooth
NPoint = 0 # Number of point created
for line in tooth_surf.get_lines():
Z = line.get_begin()
NPoint += 1
factory.addPoint(Z.real, Z.imag, -L / 2, mesh_size, NPoint)
# Draw all the lines of the tooth
NLine = 0 # Number of line created
for line in tooth_surf.get_lines():
NLine += 1
if NLine == len(tooth_surf.get_lines()):
if isinstance(line, Arc):
Zc = line.get_center()
NPoint += 1
factory.addPoint(Zc.real, Zc.imag, -L / 2, mesh_size, NPoint)
factory.addCircleArc(NLine, NPoint - 1, 1, NLine)
else:
factory.addLine(NLine, 1, NLine)
else:
if isinstance(line, Arc):
Zc = line.get_center()
NPoint += 1
factory.addPoint(Zc.real, Zc.imag, -L / 2, mesh_size, NPoint)
factory.addCircleArc(NLine, NPoint, NLine + 1, NLine)
else:
factory.addLine(NLine, NLine + 1, NLine)
# Create the Tooth surface
gmsh.model.geo.addCurveLoop(list(range(1, NLine + 1)), 1)
gmsh.model.geo.addPlaneSurface([1], 1)
gmsh.model.addPhysicalGroup(2, [1], 1)
gmsh.model.setPhysicalName(2, 1, "Tooth")
# convert triangle mesh to rectangle mesh
if is_rect:
factory.mesh.setRecombine(2, 1)
# Change the mesh size for each line
if user_mesh_dict is not None:
# Compute basic mesh_dict
mesh_dict = tooth_surf.comp_mesh_dict(element_size=mesh_size)
# Overwrite basic mesh dict with user one
mesh_dict.update(user_mesh_dict)
# Apply the number of element on each line of the surface
for ii, line in enumerate(tooth_surf.get_lines()):
factory.mesh.setTransfiniteCurve(
ii + 1, mesh_dict[str(ii)] + 1, "Progression"
)
# Copy/Rotate all the tooth to get the 2D lamination
surf_list = [1]
for ii in range(Zs):
ov = factory.copy([(2, 1)])
factory.rotate(ov, 0, 0, -L / 2, 0, 0, 1, (ii + 1) * 2 * pi / Zs)
surf_list.append(ov[0][1])
gmsh.model.addPhysicalGroup(2, surf_list, 2)
gmsh.model.setPhysicalName(2, 2, "Lamination")
# Extrude the lamination
for surf in surf_list:
if is_rect == True:
ov = factory.extrude(
[(2, surf)], 0, 0, L, numElements=[Nlayer], recombine=True
)
else:
ov = factory.extrude(
[(2, surf)], 0, 0, L, numElements=[Nlayer], recombine=False
)
model.addPhysicalGroup(3, list(range(1, Zs + 1)), 1)
if lamination.is_stator:
model.setPhysicalName(3, 1, "stator")
else:
model.setPhysicalName(3, 1, "rotor")
# Generate the 3D mesh
factory.synchronize()
filename, file_extension = splitext(save_path)
if file_extension == ".geo":
gmsh.write(filename + ".geo_unrolled")
replace(filename + ".geo_unrolled", filename + file_extension)
else:
gmsh.model.mesh.generate(3)
gmsh.write(save_path)
# Save and close
gmsh.finalize()
