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 __init__(self,
x,
y,
connections,
loads,
supports,
density=880,
unit='m',
width=0.95 / 100,
thick=1.8 / 1000,
pop_compressive_strength=18100,
pop_tensile_strength=70000):
pop_cross_area = width * thick
pop_mpl = pop_cross_area * density
g = pop_mpl * 9.81 / 1000
unit_conv = 1
if (unit == 'cm'):
unit_conv = (1 / 100)
nodes = [[x[i] * unit_conv, y[i] * unit_conv] for i in range(len(x))]
ss = SystemElements(EA=pop_cross_area * 8600000)
for node1, node2 in connections:
ss.add_element([nodes[node1], nodes[node2]],
element_type='truss',
g=g)
for node in supports:
id = ss.find_node_id(nodes[node])
ss.add_support_fixed(id)
for node, load in loads:
id = ss.find_node_id(nodes[node])
ss.point_load(id, Fy=-9.81 * load / 1000)
ss.solve()
self.ss = ss
self.nodes = nodes
self.connections = connections
self.loads = loads
self.supports = supports
self.pop_mpl = pop_mpl
self.cross_area = pop_cross_area
self.compress = pop_compressive_strength
self.tensile = pop_tensile_strength
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
for i in element_list:
inicial = i.incidences_i
final = i.incidences_f
ss.add_element(location=[[inicial.x, inicial.y], [final.x, final.y]])
# for i in range(1, len(point_list)+1):
# j = i+1
# for j in range(len(point_list)+1):
# for element in element_list:
# inicial = element.incidences_i
# final = element.incidences_f
# if i == int(inicial.name) and j == int(final.name):
# ss.add_element(location=[[inicial.x,inicial.y], [final.x, final.y]])
for i in point_list:
ponto = ss.find_node_id([i.x, i.y])
if i.x_fixed == True and i.y_fixed == False:
ss.add_support_roll(node_id=ponto, direction=1)
elif i.x_fixed == False and i.y_fixed == True:
ss.add_support_roll(node_id=ponto, direction=2)
elif i.x_fixed == True and i.y_fixed == True:
ss.add_support_fixed(node_id=ponto)
for i in load_list:
ponto = ss.find_node_id(
[point_list[int(i.point)-1].x, point_list[int(i.point)-1].y])
ss.point_load(node_id=ponto, Fx=int(
i.intensity_x), Fy=int(i.intensity_y))
ss.show_structure()
ss.solve()
ss.add_element([nodes[5],nodes_mid[5]], element_type='truss', g=g)
ss.add_element([nodes[6],nodes_mid[5]], element_type='truss', g=g)
ss.add_element([nodes[6],nodes_mid[6]], element_type='truss', g=g)
ss.add_element([nodes[7],nodes_mid[6]], element_type='truss', g=g)
ss.add_element([nodes[7],nodes_mid[7]], element_type='truss', g=g)
ss.add_element([nodes[8],nodes_mid[7]], element_type='truss', g=g)
ss.add_element([nodes[8],nodes_mid[8]], element_type='truss', g=g)
ss.add_element([nodes[9],nodes_mid[8]], element_type='truss', g=g)
#vertical beams at midpoints of triangles
ss.add_element([nodes_mid[9],nodes_mid[4]], element_type='truss', g=g)
ss.add_element([nodes[4],nodes[13]], element_type='truss', g=g)
ss.add_element([nodes[5],nodes[14]], element_type='truss', g=g)
for node in supports:
id = ss.find_node_id(nodes[node])
ss.add_support_fixed(id)
loads = [(4,9),(5,9)]
for node, load in loads:
id = ss.find_node_id(nodes_mid[node])
ss.point_load(id, Fy=-9.81*load/1000)
ss.solve()
def test(verbose=False):
arr = ss.get_element_results()
forces = [x['N'] for x in arr]
if (verbose):
print("Difference between maximum tens. pressure and tensile strength: {}".format(max(forces)/pop_cross_area - pop_tensile_strength))
