"""
defines:
- split_line_elements(bdf_model, eids, neids=2,
eid_start=1, nid_start=1)
"""
import numpy as np
from pyNastran.bdf.bdf import read_bdf
[docs]
def split_line_elements(bdf_model, eids, neids=2,
eid_start=1, nid_start=1):
"""
Splits a set of element ids
Parameters
----------
eids : list[int]
element ids to split
neids : int; default=5
how many elements should a single bar be split into
min=2
eid_start : int; default=1
the starting element id
nid_start : int; default=1
the starting node id
Returns
-------
eids_out : list[int]
the list of elements that have been added
eid_end : int; default=1
the final element id
nid_end : int; default=1
the final node id
A-----*-----B; neids=2
A--*--*--*--B; neids=4
"""
eids_out = []
assert neids >= 2, neids
dx = np.linspace(0., 1., num=neids+1)
for eid in eids:
elem = bdf_model.elements[eid]
n1, n2 = elem.nodes
node1 = bdf_model.nodes[n1]
node2 = bdf_model.nodes[n2]
cp = node1.cp
assert node1.cp == node2.cp
assert node1.cd == node2.cd
xyz1 = node1.xyz
xyz2 = node2.xyz
dxyz = xyz2 - xyz1
etype = elem.type
if etype in ['CBAR', 'CBEAM']:
pa = elem.pa
pb = 0
elem.comment = ''
comment = str(elem) + '\n'
for ieid in range(neids):
dxi = dx[ieid + 1]
new_xyz = xyz1 + dxyz * dxi
if dxi < 1.:
new_node = nid_start
nid_start += 1
bdf_model.add_grid(new_node, new_xyz, cp=cp)
else:
new_node = n2
if etype in ['CBAR', 'CBEAM']:
pb = elem.pb
if etype == 'CONROD':
nids = [n1, new_node]
bdf_model.add_conrod(eid_start, elem.mid, nids, elem.A, j=elem.j,
c=elem.c, nsm=elem.nsm, comment=comment)
elif etype == 'CROD':
nids = [n1, new_node]
bdf_model.add_crod(eid_start, elem.pid, nids, comment=comment)
elif etype == 'CBAR':
ga = n1
gb = new_node
bdf_model.add_cbar(eid_start, elem.pid, [ga, gb], elem.x, elem.g0, offt=elem.offt,
pa=pa, pb=pb, wa=elem.wa, wb=elem.wb, comment=comment)
pa = 0
elif etype == 'CBEAM':
ga = n1
gb = new_node
bdf_model.add_cbeam(eid_start, elem.pid, [ga, gb], elem.x, elem.g0,
offt=elem.offt, bit=elem.bit,
pa=pa, pb=pb,
wa=elem.wa, wb=elem.wb, sa=elem.sa, sb=elem.sb,
comment=comment)
pa = 0
else:
raise NotImplementedError(elem)
n1 = new_node
eids_out.append(eid_start)
eid_start += 1
comment = str(eid)
del bdf_model.elements[eid]
return eids_out, eid_start, nid_start
[docs]
def split_elements(bdf_filename):
"""unimplemented method for splitting elements"""
model = read_bdf(bdf_filename, xref=True)
for eid, elem in model.elements.items():
if elem.type == 'CTRIA3':
#
# 3
# /|\
# / | \
# / | \
# / 4 \
# / / \ \
# / / \ \
# 1-------------2
#
p1, p2, p3 = elem.get_node_positions()
#centroid = (p1 + p2 + p3) / 3.
#
# 3
# /|\
# / | \
# / | \
# / | \
# 1----4----2
#
elif elem.type == 'CQUAD4':
#
#
# 4---------3
# | \ / |
# | \ / |
# | 5 |
# | / \ |
# |/ \|
# 1---------2
#
# the same thing shown in a rotated view
# 4
# /| \
# / | \
# / | \
# / | \
# 1---------5---------3
# \ | /
# \ | /
# \ | /
# \ | /
# 2
#
# max_area, taper_ratio, area_ratio
# 4----7----3
# | | |
# | | |
# 8----9----6
# | | |
# | | |
# 1----4----2
#
# max_interior_angle
# 4---------3
# / \ /
# / \ /
# / \ /
# / \ /
# 1---------2
#
# taper_ratio
# 4--6--3
# / | \
# / | \
# / | \
# 1------5------2
#
# taper_ratio
# 4------3
# / \ / \
# / \ / \
# / \/ \
# 1-------5------2
#
# taper_ratio
# 4------3
# / \ \
# / \ \
# / \ \
# 1-------5------2
pass