#
##
## This file is part of pyFormex 2.0 (Mon Sep 14 12:29:05 CEST 2020)
## pyFormex is a tool for generating, manipulating and transforming 3D
## geometrical models by sequences of mathematical operations.
## Home page: http://pyformex.org
## Project page: http://savannah.nongnu.org/projects/pyformex/
## Copyright 2004-2020 (C) Benedict Verhegghe (benedict.verhegghe@ugent.be)
## Distributed under the GNU General Public License version 3 or later.
##
## This program 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.
##
## This program 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 this program. If not, see http://www.gnu.org/licenses/.
##
"""
Interface with Calculix FE result files (.dat).
"""
import re
import numpy as np
import pyformex.arraytools as at
from pyformex.plugins.fe_post import FeResult
from pyformex.mesh import Mesh
re_float = re.compile(r"[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?")
re_header = re.compile(
r" *(?P<name>[^ ]+) *\(.*\) +for set (?P<set>[^ ]+) *and time *(?P<time>[^ ]+)")
######################### functions #############################
def skipBlankLine(fil):
line = fil.next().strip()
if len(line) > 0:
raise ValueError("Expected a blank line")
# TODO: this could be speed up as done in tetgen.py
[docs]def readDispl(fil, nnodes, nres):
"""Read displacements from a Calculix .dat file"""
values = np.zeros((nnodes, nres), dtype=at.Float)
for line in fil:
if len(line.strip()) == 0:
break
s = line.split()
i = int(s[0])
x = [float(f) for f in s[1:]]
values[i-1] = x
return values
[docs]def readStress(fil, nelems, ngp, nres):
"""Read stresses from a Calculix .dat file"""
values = np.zeros((nelems, ngp, nres), dtype=at.Float)
for line in fil:
if len(line.strip()) == 0:
break
s = line.split()
i, j = [int(v) for v in s[:2]]
x = [float(v) for v in s[2:]]
values[i-1, j-1] = x
return values
[docs]def readResults(fn, DB, nnodes, nelems, ngp):
"""Read Calculix results file for nnodes, nelems, ngp
Add results to the specified DB
"""
fil = open(fn, 'r')
result = {}
step = 1
for line in fil:
m = re_header.match(line)
if m:
m = m.groupdict()
name = m['name'][:5]
setname = m['set']
time = m['time']
print("Match %s %s %s" % (name, setname, time))
skipBlankLine(fil)
if name == 'displ':
result[name] = readDispl(fil, nnodes, 3)
elif name == 'stres':
result[name] = readStress(fil, nelems, ngp, 6)
if 'displ' in result and 'stres' in result:
addFeResult(DB, step, time, result)
result = {}
step += 1
return result
[docs]def createResultDB(model):
"""Create a results database for the given FE model"""
DB = FeResult()
DB.nodes = model.coords
DB.nnodes = model.coords.shape[0]
DB.nodid = np.arange(DB.nnodes)
DB.elems = dict(enumerate(model.elems))
DB.nelems = model.celems[-1]
DB.Finalize()
return DB
[docs]def addFeResult(DB, step, time, result):
"""Add an FeResult for a time step to the result DB
This is currently 2D only
"""
print("Storing result for step %s, time %s" % (step, time))
DB.Increment(step, 0)
DB.R['TIME'] = time
if 'displ' in result:
DB.datasize['U'] = result['displ'].shape[1]
DB.R['U'] = result['displ']
if 'stres' in result:
try:
stress = result['stres']
# CALCULIX HAS NO 2D: keep only half of GP's
ngp = stress.shape[1]//2
stress = stress[:, :ngp, :]
print("Reduced stresses: %s" % str(stress.shape))
mesh = Mesh(DB.nodes, DB.elems[0], eltype='quad4')
gprule = [2, 2]
stress = computeAveragedNodalStresses(mesh, stress, gprule)
DB.datasize['S'] = result['stres'].shape[1]
DB.R['S'] = stress
except Exception:
print("Error importing stresses")
return DB
[docs]def computeAveragedNodalStresses(M, data, gprule):
"""Compute averaged nodal stresses from GP stresses in 2D quad8 mesh"""
############################
# Load the needed calpy modules
from pyformex.plugins import calpy_itf
calpy_itf.check()
gprule = (2, 2) # integration rule: minimum (1,1), maximum (5,5)
Q = calpy_itf.QuadInterpolator(M.nelems(), M.nplex(), gprule)
ngp = np.prod(gprule) # number of datapoints per element
print("Number of data points per element: %s" % ngp)
print("Original element data: %s" % str(data.shape))
# compute the data at the nodes, per element
endata = Q.GP2Nodes(data)
print("Element nodal data: %s" % str(endata.shape))
# compute nodal averages
nodata = Q.NodalAvg(M.elems+1, endata, M.nnodes())
print("Average nodal data: %s" % str(nodata.shape))
# extract the colors per element
return nodata
# End
