Source code for felupe.tools._save
# -*- coding: utf-8 -*-
"""
This file is part of FElupe.
FElupe is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
FElupe 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with FElupe. If not, see <http://www.gnu.org/licenses/>.
"""
import numpy as np
from ..math import det, dot, eigvalsh, transpose
from . import topoints
[docs]
def save(
region,
field,
forces=None,
gradient=None,
filename="result.vtu",
cell_data=None,
point_data=None,
):
"""Write field-data to a VTU file.
Parameters
----------
region : Region
The region to be saved.
field : FieldContainer
The field container to be saved.
forces : ndarray, optional
Array with reaction forces to be saved (default is None).
gradient : list of ndarray, optional
The result of ``umat.gradient()`` with the first Piola-Kirchhoff stress tensor
as the first list item (default is None).
filename : str, optional
The filename for the results (default is "result.vtu").
cell_data : dict or None, optional
Additional dict with cell data (default is None).
point_data : dict or None, optional
Additional dict with point data (default is None).
Examples
--------
>>> import felupe as fem
>>>
>>> mesh = fem.Cube(n=6)
>>> region = fem.RegionHexahedron(mesh)
>>> field = fem.FieldContainer([fem.Field(region, dim=3)])
>>>
>>> boundaries, loadcase = fem.dof.uniaxial(field, clamped=True, move=0.3)
>>>
>>> umat = fem.NeoHooke(mu=1)
>>> solid = fem.SolidBodyNearlyIncompressible(umat, field, bulk=5000)
>>> step = fem.Step(items=[solid], boundaries=boundaries)
>>> job = fem.CharacteristicCurve(steps=[step], boundary=boundaries["move"]).evaluate()
>>> fem.save(region, field, forces=job.res.fun, gradient=solid.results.stress)
"""
u = field.fields[0]
mesh = region.mesh
offsets = field.offsets
if point_data is None:
point_data = {}
point_data["Displacements"] = u.values
if forces is not None:
reactionforces = np.split(forces, offsets)[0]
point_data["Reaction Force"] = reactionforces.reshape(*u.values.shape)
if gradient is not None:
# 1st Piola Kirchhoff stress
F = field.extract()[0]
P = gradient[0]
# cauchy stress at integration points
s = dot(P, transpose(F)) / det(F)
sp = eigvalsh(s)
# shift stresses to points and average nodal values
cauchy = topoints(s, region=region)
cauchyprinc = topoints(sp, region=region)
point_data["Cauchy Stress"] = cauchy
point_data["Cauchy Stress (Max. Principal)"] = cauchyprinc[:, 2]
point_data["Cauchy Stress (Int. Principal)"] = cauchyprinc[:, 1]
point_data["Cauchy Stress (Min. Principal)"] = cauchyprinc[:, 0]
point_data["Cauchy Stress (Max. Principal Shear)"] = (
cauchyprinc[:, 2] - cauchyprinc[:, 0]
)
import meshio
mesh = meshio.Mesh(
points=mesh.points,
cells=[
(mesh.cell_type, mesh.cells),
],
point_data=point_data,
cell_data=cell_data,
)
mesh.write(filename)