def generate_truss_by_grid(grid, enabled):
"""
enabled is a list of booleans indicating which members in the grid are enabled. Length must match the total possible members in the grid
"""
enabled = np.array(enabled)
width = MIN_WIDTH / 2
height = MAX_HEIGHT
all_possible_members = grid
# print(f"number of possible members: {len(all_possible_members)}")
assert len(all_possible_members) == len(enabled)
members = all_possible_members[enabled]
print(f"members selected: {len(members)}")
# mirror the members to the right side
members_mirror = np.copy(members)
for member in members_mirror:
for point in member:
point[0] *= -1
point[0] += width * 2
members = np.append(members, members_mirror, axis=0)
truss = SystemElements(EA=MODULUS_OF_ELASTICITY * BRASS_CROSS_SECTION_AREA,
EI=MODULUS_OF_ELASTICITY * MOMENT_OF_INERTIA)
for member in members:
truss.add_truss_element(member)
try:
truss.add_support_hinged(node_id=truss.find_node_id(vertex=[0, 0]))
truss.add_support_hinged(node_id=truss.find_node_id(
vertex=[width * 2, 0]))
return truss
except:
return None
def makestructure(nodes,
segs,
fixednodes,
loadnodes,
thicknesses,
tensile=tensilePLA,
totalload=100):
ss = SystemElements()
#loop through segments and create them
for s, thickness in zip(segs, thicknesses):
ss.add_truss_element(location=[nodes[s[0]], nodes[s[1]]],
EA=tensile * thickness * strutwidth,
g=0,
spring={
1: 0.0001,
2: 0.0001
})
#
for f, supporttype in fixednodes:
if supporttype == 'hinged':
ss.add_support_hinged(node_id=f + 1)
elif supporttype == 'roll':
ss.add_support_roll(node_id=f + 1, direction='x')
elif supporttype == 'fixed':
ss.add_support_fixed(node_id=f + 1)
#add in other types of supports here
for l in loadnodes:
ss.point_load(l + 1, Fx=0, Fy=-totalload / len(loadnodes))
return ss
#!/usr/bin/env python3 from anastruct import SystemElements import math width = 15 height = 4 ss = SystemElements(EA=15000, EI=5000) ss.add_truss_element(location=[[0, 0], [0, height]]) ss.add_truss_element(location=[[0, 0], [width, 0]]) ss.add_truss_element(location=[[0, 4], [width, height]]) ss.add_truss_element(location=[[width, height], [width, 0]]) ss.add_truss_element(location=[[0, height], [width/4, 0]]) ss.add_truss_element(location=[[width/4*2, height], [width/4, 0]]) ss.add_truss_element(location=[[width/4*2, height], [width/4*3, 0]]) ss.add_truss_element(location=[[width, height], [width/4*3, 0]]) ss.add_support_fixed(node_id=ss.find_node_id(vertex=[0, 0])) ss.add_support_fixed(node_id=ss.find_node_id(vertex=[15, 0])) ss.point_load(Fy=-300, node_id=ss.find_node_id(vertex=[width/2, height])) ss.solve() # Get visual results. ss.show_structure() # ss.show_reaction_force() # ss.show_axial_force() # ss.show_shear_force() # ss.show_bending_moment() # ss.show_displacement()
def generate_truss(subdivide_mode=None, subdivides=None):
"""
Randomly generate a valid truss
"""
ss = SystemElements(EA=MODULUS_OF_ELASTICITY * BRASS_CROSS_SECTION_AREA,
EI=MODULUS_OF_ELASTICITY * MOMENT_OF_INERTIA)
width = MIN_WIDTH
height = MAX_HEIGHT
if not subdivide_mode:
subdivide_mode = random.choice(
["triangle_subdivide", "radial_subdivide", "pillar_subdivide"])
if subdivide_mode == "triangle_subdivide":
if not subdivides:
subdivides = random.randint(1, 2)
triangles = [
[
[[0, 0], [width, 0]],
[[width, 0], [width / 2, height]],
[[width / 2, height], [0, 0]],
],
]
for _ in range(subdivides):
new_triangles = []
for triangle in triangles:
mids = [midpoint(*line) for line in triangle]
new_triangles += [
[
[triangle[0][0], mids[0]],
[mids[0], mids[2]],
[mids[2], triangle[0][0]],
],
[
[mids[2], mids[1]],
[mids[1], triangle[2][0]],
[triangle[2][0], mids[2]],
],
[
[mids[0], triangle[1][0]],
[triangle[1][0], mids[1]],
[mids[1], mids[0]],
],
[
[mids[2], mids[0]],
[mids[0], mids[1]],
[mids[1], mids[2]],
],
]
triangles = new_triangles
raw_lines = np.reshape(triangles, (-1, 2, 2))
# sort coordinates in each line
raw_lines = [sorted(line, key=lambda p: p[0]) for line in raw_lines]
# sort lines by first point's x value
raw_lines = sorted(raw_lines, key=lambda l: l[0][0])
# remove duplicate lines
lines = []
for line in raw_lines:
is_duplicate = False
for l in lines:
if np.array_equal(line, l):
is_duplicate = True
if not is_duplicate:
lines.append(line)
for line in lines:
ss.add_truss_element(location=line)
elif subdivide_mode == "radial_subdivide":
if not subdivides:
subdivides = random.randint(1, 4)
step_size = width / 2 / subdivides
bottom_midpoint = midpoint([0, 0], [width, 0])
lines = []
for x in np.arange(0, width + 0.1, step_size):
lines += [
[
bottom_midpoint,
[
x,
valmap(x, 0, width / 2, 0, height) if x <= width / 2
else valmap(x, width / 2, width, height, 0)
]
],
]
lines[-1][1][1] = 0 # HACK: set last y value to 0
top_points = [p[1] for p in lines]
top_lines = []
for i in range(1, len(top_points)):
top_lines += [[top_points[i - 1], top_points[i]]]
lines += top_lines
for line in lines:
ss.add_truss_element(location=line)
elif subdivide_mode == "pillar_subdivide":
if not subdivides:
subdivides = random.randint(1, 4)
step_size = width / 2 / subdivides
lines = []
for x in np.arange(step_size, width, step_size):
lines += [
[[x, 0],
[
x,
valmap(x, 0, width / 2, 0, height) if x <= width / 2 else
valmap(x, width / 2, width, height, 0)
]],
]
top_points = [p[1] for p in lines]
edge_lines = []
for i in range(1, len(top_points)):
edge_lines += [
[top_points[i - 1], top_points[i]],
[[top_points[i - 1][0], 0], [top_points[i][0], 0]],
]
if i < len(top_points) / 2:
edge_lines += [
[[top_points[i - 1][0], 0], top_points[i]],
]
else:
edge_lines += [
[top_points[i - 1], [top_points[i][0], 0]],
]
lines += [
[[0, 0], top_points[0]],
[[0, 0], [top_points[0][0], 0]],
[[width, 0], top_points[-1]],
[[width, 0], [top_points[-1][0], 0]],
]
lines += edge_lines
for line in lines:
ss.add_truss_element(location=line)
ss.add_support_hinged(node_id=ss.find_node_id(vertex=[0, 0]))
ss.add_support_hinged(node_id=ss.find_node_id(vertex=[width, 0]))
return ss
def accept(self):
try:
E = float(self.form.editE.text()) # N/mm2
I = float(self.form.editI.text()) # mm4
A = float(self.form.editA.text()) # mm2
ss = SystemElements()
frame = FreeCAD.ActiveDocument.getObjectsByLabel(
self.form.comboBox.currentText())[0]
sk = frame.Base
j = 0
# CREATE MEMBERS OF STRUCTURE
for l in sk.Geometry:
sp = [i * 1e-3 for i in list(l.StartPoint)[:2]]
ep = [i * 1e-3 for i in list(l.EndPoint)[:2]]
if self.combotypes[j].currentText() == 'beam':
ss.add_element([sp, ep], EA=E * A * 1e-3, EI=E * I * 1e-9)
elif self.combotypes[j].currentText() == 'brace':
ss.add_truss_element([sp, ep], EA=E * A * 1e-3)
j += 1
# SET DISTRIBUTED LOADS
if self.form.radioFrame.isChecked():
for i in list(range(len(sk.Geometry))):
if self.form.tableDistrib.item(i, 2):
item = self.form.tableDistrib.item(i, 2)
try:
load = float(item.text()) # kN/m
ss.q_load(element_id=(i + 1), q=load)
except:
pass
for c in self.combos:
i = self.combos.index(c) + 1
# SET NODE CONSTRAINTS
if c.currentText() == 'fix': ss.add_support_fixed(node_id=i)
elif c.currentText() == 'hinge':
ss.add_support_hinged(node_id=i)
elif c.currentText() == 'roll':
ss.add_support_roll(node_id=i)
# SET NODE FORCES
if self.form.tableConc.item(
i - 1, 1) or self.form.tableConc.item(i - 1, 2):
itemX = self.form.tableConc.item(i - 1, 1)
try:
loadX = float(itemX.text()) # kN
except:
loadX = 0
itemY = self.form.tableConc.item(i - 1, 2) # kN
try:
loadY = float(itemY.text())
except:
loadY = 0
ss.point_load(node_id=(i), Fx=loadX, Fy=loadY)
# SOLVE AND VALIDATE
ss.solve()
# stable=ss.validate(.0000001)
# SHOW RESULTS ACCORDING THE CALC TYPE
if True: #stable:
if self.form.radioFrame.isChecked():
ss.show_results()
elif self.form.radioTruss.isChecked():
ss.show_axial_force()
else:
FreeCAD.Console.PrintError('The structure is not stable.\n')
except:
FreeCAD.Console.PrintError('Invalid input\n')
for l in self.labNodes + self.labEl:
l.removeLabel()
def trussbridge(Ediag,
Adiag,
Ebot,
Abot,
Etop,
Atop,
p,
w_tri=4,
h_tri=2,
num_tri=6,
disp=False):
"""
Calculate displacement of middle point in bridge truss
Args:
Ediag (list): list of Young's modulus for each pair of diagonal trusses (Pa)
Adiag (list): list of cross-sectional area for each pair of diagonal trusses (m2)
Ebot (list): list of Young's modulus for each bottom truss (Pa)
Abot (list): list of cross-sectional area for each bottom truss (m2)
Etop (list): list of Young's modulus for each top truss (Pa)
Atop (list): list of cross-sectional area for each top truss (m2)t
p (list): list of force applied on the top nodes (N)
num_tri (int): number of triangles
disp (bool): display image or not
"""
Ediag = np.array(Ediag)
Adiag = np.array(Adiag)
Ebot = np.array(Ebot)
Abot = np.array(Abot)
Etop = np.array(Etop)
Atop = np.array(Atop)
EAdiag = Ediag * Adiag
EAbot = Ebot * Abot
EAtop = Etop * Atop
ss = SystemElements()
# Triangle coord
x_base = np.arange(0, num_tri + 1) * w_tri
x_top = np.arange(0, num_tri) * w_tri + h_tri
y = np.ones(num_tri) * h_tri
# Create 6 triangles
for i in range(num_tri):
p1 = [x_base[i], 0]
p2 = [x_top[i], y[i]]
p3 = [x_base[i + 1], 0]
ss.add_truss_element(location=[p1, p2], EA=EAdiag[i])
ss.add_truss_element(location=[p2, p3], EA=EAdiag[i])
ss.add_truss_element(location=[p1, p3], EA=EAbot[i])
# Create 5 horizontal trusses
for i in range(num_tri - 1):
ss.add_truss_element(location=[[x_top[i], y[i]],
[x_top[i + 1], y[i + 1]]],
EA=EAtop[i])
# Create support
ss.add_support_hinged(node_id=1)
ss.add_support_roll(node_id=13, direction=2)
# Create Load
loadnode = [2, 4, 6, 8, 12]
for index, point in enumerate(loadnode):
ss.point_load(node_id=point, Fy=p[index])
ss.point_load(node_id=point, Fy=p[index])
ss.point_load(node_id=point, Fy=p[index])
ss.point_load(node_id=point, Fy=p[index])
ss.solve()
disp7 = ss.get_node_displacements(node_id=7)
if disp is True:
ss.show_axial_force()
ss.show_displacement(factor=10)
return disp7