def initializeLatticeShell(startPoint,
latticeParam,
xHexagons,
yHexagons,
force=10,
theta=0,
elasticModulus=17000000000,
moment=5000000,
area=0.0005,
g=0,
invertHex=True,
saveDir=None):
'''
This function takes in initial parameters for a hexagon lattice, creates
a mesh structure using the anaStruct library object SystemElements(). First,
the center points of hexagons in the lattice will be generated, the hexagon
vertices will be saved in a custom NumPy array to save the center points and
al 6 vertices.
The numpy array will hold 7 tuples( 1 tuple for the center-point, 6 tuples for
coordinates of each hexagon vertex. )
Args:
(startPoint):
(tuple): Tuple of dtype=np.float64 or dtype=np.float32 housing the
original start point (bottom left) of the hexagon lattice to be constructed.
(latticeParam):
(float): The length of each 'sub triangle' length starting from the center
of the hexagon to each vertex.
(xHexagons):
(int): Number of hexagons to be constructed in the x-direction in the lattice.
(yHexagons):
(int): Number of hexagons to be constructed in the y-direction in the lattice.
Returns:
(lattice):
(SystemElements() Object): The system elements object containing all trusses
defined and fully constrained.
(lattice_coordinatews):
(numpy array): Custom numpy array of shape=( xHexagons, yHexagons, 7, 2 ).
Contains 7 coordinates per hexagon: Center coords, and vertex coordinates.
'''
# Initialize finite element material parameters
EA = elasticModulus * area
EI = elasticModulus * moment
# Initialize timer
start = timeit.default_timer()
# Initialize anaStruct.py SystemElements() object...
# ss = SystemElements(figsize=(12,8), EA=15000.0, EI=5e3)
ss = SystemElements(EA=EA, EI=EI)
'''
EA - Standard axial stiffness of element
EI - Standard bending stiffness of elements
figsize - Matplotlibs standard figure size (inches)
'''
# Initialize custom numpy array...
lattice_coordinates = np.empty(shape=(xHexagons + 1, yHexagons, 7, 2))
# Take not of all elements that are already saved so we don't repeat them
# Save initialized system elements points as an array to be referenfced when
# creating new system elements to the FEM mesh.
old_ss = []
# Initialize hexagon lattice centers:
lattice_centers = getHexagonLatticeCenters(startPoint,
latticeParam,
xHexagons,
yHexagons,
invertHex=invertHex)
print(lattice_centers)
# Iterate through each hexagon center and fill lattice_coordinates numpy array
for j in range(yHexagons):
# Every odd numbered row (0 start counting) will have 1 extra hexagon to be drawn in.
if j % 2 != 0:
xHexagonCount = xHexagons + 1
else:
xHexagonCount = xHexagons
for i in range(xHexagonCount):
# Get hexagon points
curr_hexPoints = hexagonPoints(lattice_centers[i, j],
latticeParam,
invertHex=invertHex)
# Initialize start point
lattice_coordinates[i, j, 0] = lattice_centers[i, j]
lattice_coordinates[i, j, 1:] = curr_hexPoints
# Iterating through first hexagon being drawn
if i == 0:
# For even values:
if j % 2 != 0:
# Finds the point pair list of the right half of the hexagon
point_pair_list = [
(curr_hexPoints[1], curr_hexPoints[0]),
(curr_hexPoints[0], curr_hexPoints[5]),
(curr_hexPoints[5], curr_hexPoints[4]),
]
for k in range(3):
# Check if current element is already added
is_added, index = checkSystemElement(
point_pair_list[k][0], point_pair_list[k][1],
old_ss)
# Check if element exists
if is_added == False:
ss.add_element(location=[
point_pair_list[k][0], point_pair_list[k][1]
],
EA=EA,
EI=EI,
g=g)
old_ss.append(
(point_pair_list[k][0], point_pair_list[k][1]))
else:
print(
"Point Pair {} has already been added at index {} of old_ss list."
.format(curr_point_pair, index))
else:
# Iterate through all point pairs:
for k in range(6):
curr_point_pair = (curr_hexPoints[k - 1],
curr_hexPoints[k])
is_added, index = checkSystemElement(
curr_point_pair[0], curr_point_pair[1], old_ss)
# If element doesn't already exist, add it to the mesh
if is_added == False:
ss.add_element(location=[
curr_hexPoints[k - 1], curr_hexPoints[k]
],
EA=EA,
EI=EI,
g=g)
old_ss.append(
(curr_hexPoints[k - 1], curr_hexPoints[k]))
else:
# save elements added
# old_ss.append( curr_hexPoints[k-1], curr_hexPoints[k] )
# testing line --------------------
print(
"Point Pair {} has already been added at index {} of old_ss list."
.format(curr_point_pair, index))
# end testing line ------------------
elif j % 2 != 0 and i == xHexagons:
# Uneven row numbers
if j % 2 != 0:
# Finds the point pair list of the right half of the hexagon
point_pair_list = [
(curr_hexPoints[1], curr_hexPoints[2]),
(curr_hexPoints[2], curr_hexPoints[3]),
(curr_hexPoints[3], curr_hexPoints[4]),
]
for k in range(3):
# Check if current element is already added
is_added, index = checkSystemElement(
point_pair_list[k][0], point_pair_list[k][1],
old_ss)
# Check if element exists
if is_added == False:
ss.add_element(location=[
point_pair_list[k][0], point_pair_list[k][1]
],
EA=EA,
EI=EI,
g=g)
old_ss.append(
(point_pair_list[k][0], point_pair_list[k][1]))
else:
print(
"Point Pair {} has already been added at index {} of old_ss list."
.format(curr_point_pair, index))
# Even hexagon values:
else:
for k in range(6):
# check if current element is already added...if not, add it!
curr_point_pair = (curr_hexPoints[k - 1],
curr_hexPoints[k])
is_added, index = checkSystemElement(
curr_point_pair[0], curr_point_pair[1], old_ss)
# If element doesn't already exist, add it to the mesh
if is_added == False:
ss.add_element(location=[
curr_hexPoints[k - 1], curr_hexPoints[k]
],
EA=EA,
EI=EI,
g=g)
old_ss.append(
(curr_hexPoints[k - 1], curr_hexPoints[k]))
else:
# save elements added
# old_ss.append( curr_hexPoints[k-1], curr_hexPoints[k] )
# testing line --------------------
print(
"Point Pair {} has already been added at index {} of old_ss list."
.format(curr_point_pair, index))
# end testing line ------------------
# add all system elements and save point pairs
else:
for k in range(6):
# check if current element is already added...if not, add it!
curr_point_pair = (curr_hexPoints[k - 1],
curr_hexPoints[k])
is_added, index = checkSystemElement(
curr_point_pair[0], curr_point_pair[1], old_ss)
# If element doesn't already exist, add it to the mesh
if is_added == False:
ss.add_element(location=[
curr_hexPoints[k - 1], curr_hexPoints[k]
],
EA=EA,
EI=EI,
g=g)
old_ss.append(
(curr_hexPoints[k - 1], curr_hexPoints[k]))
else:
# save elements added
# old_ss.append( curr_hexPoints[k-1], curr_hexPoints[k] )
# testing line --------------------
print(
"Point Pair {} has already been added at index {} of old_ss list."
.format(curr_point_pair, index))
# end testing line ------------------
end = timeit.default_timer()
total_time = np.round((end - start), 2)
print(
"\n\nGenerating hexagon mesh of x-y dimensions, {}-{}, lattice parameter, {}, took {} seconds.\n\n"
.format(xHexagons, yHexagons, latticeParam, total_time))
lowest_nodes = findLowestNodes(ss, startPoint, latticeParam, xHexagons,
yHexagons)
highest_nodes = findHighestNodes(ss, startPoint, latticeParam, xHexagons,
yHexagons)
# add supports and flattening elements
for i in range(len(lowest_nodes)):
ss.add_element(location=[lowest_nodes[i - 1][1], lowest_nodes[i][1]])
old_ss.append((lowest_nodes[i - 1], lowest_nodes[i]))
# add fixed support on lowest nodes...
ss.add_support_fixed(node_id=lowest_nodes[i][0])
# add forces and node locations
for i in range(len(highest_nodes)):
ss.add_element(location=[highest_nodes[i - 1][1], highest_nodes[i][1]])
old_ss.append((highest_nodes[i - 1], highest_nodes[i]))
# add forces at highest nodes...
# ss.q_load(q=-1, element_id=highest_nodes[i], direction='element')
ss.point_load(node_id=highest_nodes[i][0],
Fx=0,
Fy=force,
rotation=theta)
# Solve and time it
solveTimeStart = np.round(timeit.default_timer(), 2)
ss.solve()
solveTimeEnd = np.round(timeit.default_timer(), 2)
total_solve_time = solveTimeEnd - solveTimeStart
print(
"\n\nSolving beam element model of x-y dimensions, {}-{}, lattice parameter, {}, took {} seconds.\n\n"
.format(xHexagons, yHexagons, latticeParam, total_solve_time))
# Calculate average displacement of nodes
totalDisplacement = 0
displacements = ss.get_node_displacements(node_id=0)
for i in range(len(displacements)):
totalDisplacement += np.sqrt(displacements[i][1]**2 +
displacements[i][2]**2)
averageDisplacements = totalDisplacement / len(displacements)
print("\n\nAverage Node Displacement: {}mm".format(averageDisplacements *
1000))
if saveDir != None:
diagnosticData = []
diagnosticData.append(
"Hexagon Lattice ({}-x-hexagons,{}-y-hexagons)\n".format(
xHexagons, yHexagons))
diagnosticData.append("Lattice Parameter: {}mm\n".format(latticeParam))
diagnosticData.append("Force: {}N\n".format(force))
diagnosticData.append("Elastic Modulus: {}MPa\n".format(
elasticModulus / 1000))
diagnosticData.append("Second Moment of Area: {}\n".format(moment))
diagnosticData.append("Area: {}mm\n".format(area * 1000))
diagnosticData.append("Bending Stiffness: {}\n".format(elasticModulus *
moment))
diagnosticData.append(
"Average Displacement: {}mm\n".format(averageDisplacements))
diagnosticData.append("Mesh Generated in {}s\n".format(total_time))
diagnosticData.append(
"Beam Element Model Solved in {}s\n".format(total_solve_time))
folderDir = snr.createFolder(
saveDir,
"a={}mm A={}mm f={}N E={}MPa".format(latticeParam, area, force,
elasticModulus / 1000))
textFile = open("{}\\diagnostics.txt".format(folderDir), 'w')
textFile.writelines(diagnosticData)
textFile.close()
# beam element model is solved in the call of this function.
saveElementModel(
ss, folderDir,
"a={}mm A={}mm f={}N E={}MPa".format(latticeParam, area, force,
elasticModulus / 1000))
return ss
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
