def random_var(self, is_random, *args):
"""Generate a list of objects as random attributes.
This function creates a list of objects with random values for selected
attributes from ross.Material.
Parameters
----------
is_random : list
List of the object attributes to become stochastic.
*args : dict
Dictionary instanciating the ross.Material class.
The attributes that are supposed to be stochastic should be
set as lists of random variables.
Returns
-------
f_list : generator
Generator of random objects.
"""
args_dict = args[0]
new_args = []
for i in range(len(args_dict[is_random[0]])):
arg = []
for key, value in args_dict.items():
if key in is_random:
arg.append(value[i])
else:
arg.append(value)
new_args.append(arg)
f_list = (Material(*arg) for arg in new_args)
return f_list
def load_shaft_from_xltrc(file, sheet_name='Model'):
"""Load shaft from xltrc.
This method will construct a shaft loading the geometry
and materials from a xltrc file.
Parameters
----------
file : str
File path name.
sheet_name : str
Shaft sheet name. Default is 'Model'.
Returns
-------
shaft : list
List with the shaft elements.
Examples
--------
"""
df = pd.read_excel(file, sheet_name=sheet_name)
geometry = pd.DataFrame(df.iloc[19:])
geometry = geometry.rename(columns=df.loc[18])
geometry = geometry.dropna(thresh=3)
material = df.iloc[3:13, 9:15]
material = material.rename(columns=df.iloc[0])
material = material.dropna(axis=0, how='all')
# change to SI units
if df.iloc[1, 1] == 'inches':
for dim in ['length', 'od_Left', 'id_Left', 'od_Right', 'id_Right']:
geometry[dim] = geometry[dim] * 0.0254
geometry['axial'] = geometry['axial'] * 4.44822161
for prop in ['Elastic Modulus E', 'Shear Modulus G']:
material[prop] = material[prop] * 6894.757
material['Density r'] = material['Density r'] * 27679.904
colors = [
'#636363', '#969696', '#bdbdbd', '#d9d9d9', '#636363', '#969696',
'#bdbdbd', '#d9d9d9'
]
materials = {}
for i, mat in material.iterrows():
materials[mat.Material] = Material(name=f'Material{mat["Material"]}',
rho=mat['Density r'],
E=mat['Elastic Modulus E'],
G_s=mat['Shear Modulus G'],
color=colors[mat['Material']])
return (geometry, materials)
shaft = [
ShaftElement(el.length,
el.id_Left,
el.od_Left,
materials[el.matnum],
n=el.elemnum - 1) for i, el in geometry.iterrows()
]
return shaft
def read_table_file(file, element, sheet_name=0, n=0, sheet_type="Model"):
"""Instantiate one or more element objects using inputs from an Excel table.
Parameters
----------
file: str
Path to the file containing the shaft parameters.
element: str
Specify the type of element to be instantiated: bearing, shaft or disk.
sheet_name: int or str, optional
Position of the sheet in the file (starting from 0) or its name. If none is passed, it is
assumed to be the first sheet in the file.
n: int
Exclusive for bearing elements, since this parameter is given outside the table file.
sheet_type: str
Exclusive for shaft elements, as they have a Model table in which more information can be passed,
such as the material parameters.
Returns
-------
A dictionary of parameters.
Examples
--------
>>> import os
>>> file_path = os.path.dirname(os.path.realpath(__file__)) + '/tests/data/shaft_si.xls'
>>> read_table_file(file_path, "shaft", sheet_type="Model", sheet_name="Model") # doctest: +ELLIPSIS
{'L': [0.03...
"""
df = pd.read_excel(file, header=None, sheet_name=sheet_name)
# Assign specific values to variables
parameter_columns = {}
optional_parameter_columns = {}
header_key_word = ""
default_dictionary = {}
parameters = {}
if element == "bearing":
header_key_word = "kxx"
parameter_columns["kxx"] = ["kxx"]
parameter_columns["cxx"] = ["cxx"]
optional_parameter_columns["kyy"] = ["kyy"]
optional_parameter_columns["kxy"] = ["kxy"]
optional_parameter_columns["kyx"] = ["kyx"]
optional_parameter_columns["cyy"] = ["cyy"]
optional_parameter_columns["cxy"] = ["cxy"]
optional_parameter_columns["cyx"] = ["cyx"]
optional_parameter_columns["w"] = ["w", "speed"]
default_dictionary["kyy"] = None
default_dictionary["kxy"] = 0
default_dictionary["kyx"] = 0
default_dictionary["cyy"] = None
default_dictionary["cxy"] = 0
default_dictionary["cyx"] = 0
default_dictionary["w"] = None
elif element == "shaft":
if sheet_type == "Model":
header_key_word = "od_left"
else:
header_key_word = "material"
parameter_columns["L"] = ["length"]
parameter_columns["i_d"] = ["i_d", "id", "id_left"]
parameter_columns["o_d"] = ["o_d", "od", "od_left"]
parameter_columns["material"] = ["material", "matnum"]
optional_parameter_columns["n"] = ["n", "elemnum"]
optional_parameter_columns["axial_force"] = [
"axial_force",
"axial force",
"axial",
]
optional_parameter_columns["torque"] = ["torque"]
optional_parameter_columns["shear_effects"] = [
"shear_effects", "shear effects"
]
optional_parameter_columns["rotary_inertia"] = [
"rotary_inertia",
"rotary inertia",
]
optional_parameter_columns["gyroscopic"] = ["gyroscopic"]
optional_parameter_columns["shear_method_calc"] = [
"shear_method_calc",
"shear method calc",
]
default_dictionary["n"] = None
default_dictionary["axial_force"] = 0
default_dictionary["torque"] = 0
default_dictionary["shear_effects"] = True
default_dictionary["rotary_inertia"] = True
default_dictionary["gyroscopic"] = True
default_dictionary["shear_method_calc"] = "cowper"
elif element == "disk":
header_key_word = "ip"
parameter_columns["n"] = ["unnamed: 0", "n"]
parameter_columns["m"] = ["m", "mass"]
parameter_columns["Id"] = ["it", "id"]
parameter_columns["Ip"] = ["ip"]
# Find table header and define if conversion is needed
header_index = -1
header_found = False
convert_to_metric = False
convert_to_rad_per_sec = False
for index, row in df.iterrows():
for i in range(0, row.size):
if isinstance(row[i], str):
if not header_found:
if row[i].lower() == header_key_word:
header_index = index
header_found = True
if "inches" in row[i].lower() or "lbm" in row[i].lower():
convert_to_metric = True
if "rpm" in row[i].lower():
convert_to_rad_per_sec = True
if header_found and convert_to_metric and convert_to_rad_per_sec:
break
if header_found and convert_to_metric:
break
if not header_found:
raise ValueError(
"Could not find the header. Make sure the table has a header "
"containing the names of the columns. In the case of a " +
element + ", "
"there should be a column named " + header_key_word + ".")
# Get specific data from the file
new_materials = {}
if element == "shaft" and sheet_type == "Model":
material_header_index = -1
material_header_found = False
material_header_key_word = "matno"
for index, row in df.iterrows():
for i in range(0, row.size):
if isinstance(row[i], str):
if row[i].lower() == material_header_key_word:
material_header_index = index
material_header_found = True
break
if material_header_found:
break
if not material_header_found:
raise ValueError(
"Could not find the header for the materials. Make sure the table has a header "
"with the parameters for the materials that will be used. There should be a column "
"named " + material_header_key_word + ".")
df_material = pd.read_excel(file,
header=material_header_index,
sheet_name=sheet_name)
material_name = []
material_rho = []
material_e = []
material_g_s = []
for index, row in df_material.iterrows():
if not pd.isna(row["matno"]):
material_name.append(int(row["matno"]))
material_rho.append(row["rhoa"])
material_e.append(row["ea"])
material_g_s.append(row["ga"])
else:
break
if convert_to_metric:
for i in range(0, len(material_name)):
material_rho[i] = material_rho[i] * 27679.904
material_e[i] = material_e[i] * 6894.757
material_g_s[i] = material_g_s[i] * 6894.757
for i in range(0, len(material_name)):
new_material = Material(
name="shaft_mat_" + str(material_name[i]),
rho=material_rho[i],
E=material_e[i],
G_s=material_g_s[i],
)
new_materials["shaft_mat_" + str(material_name[i])] = new_material
df = pd.read_excel(file, header=header_index, sheet_name=sheet_name)
df.columns = df.columns.str.lower()
# Find and isolate data rows
first_data_row_found = False
last_data_row_found = False
indexes_to_drop = []
for index, row in df.iterrows():
if (not first_data_row_found
and (isinstance(row[header_key_word], int)
or isinstance(row[header_key_word], float))
and not pd.isna(row[header_key_word])):
first_data_row_found = True
elif not first_data_row_found:
indexes_to_drop.append(index)
elif first_data_row_found and not last_data_row_found:
if (isinstance(row[header_key_word], int) or isinstance(
row[header_key_word],
float)) and not pd.isna(row[header_key_word]):
continue
else:
last_data_row_found = True
indexes_to_drop.append(index)
elif last_data_row_found:
indexes_to_drop.append(index)
if not first_data_row_found:
raise DataNotFoundError(
"Could not find the data. Make sure you have at least one row containing "
"data below the header.")
if len(indexes_to_drop) > 0:
df = df.drop(indexes_to_drop)
# Build parameters list
if element == "bearing":
parameters["n"] = n
for key, value in parameter_columns.items():
for name in value:
try:
parameters[key] = df[name].tolist()
break
except KeyError:
if name == value[-1]:
raise ValueError(
"Could not find a column with one of these names: " +
str(value))
continue
for key, value in optional_parameter_columns.items():
for name in value:
try:
parameters[key] = df[name].tolist()
break
except KeyError:
if name == value[-1]:
parameters[key] = [default_dictionary[key]] * df.shape[0]
else:
continue
if element == "shaft":
new_n = parameters["n"]
for i in range(0, df.shape[0]):
new_n[i] -= 1
parameters["n"] = new_n
if sheet_type == "Model":
new_material = parameters["material"]
for i in range(0, df.shape[0]):
new_material[i] = "shaft_mat_" + str(int(new_material[i]))
parameters["material"] = new_material
if convert_to_metric:
for i in range(0, df.shape[0]):
if element == "bearing":
parameters["kxx"][i] = parameters["kxx"][i] * 175.126_836_986_4
parameters["cxx"][i] = parameters["cxx"][i] * 175.126_836_986_4
parameters["kyy"][i] = parameters["kyy"][i] * 175.126_836_986_4
parameters["kxy"][i] = parameters["kxy"][i] * 175.126_836_986_4
parameters["kyx"][i] = parameters["kyx"][i] * 175.126_836_986_4
parameters["cyy"][i] = parameters["cyy"][i] * 175.126_836_986_4
parameters["cxy"][i] = parameters["cxy"][i] * 175.126_836_986_4
parameters["cyx"][i] = parameters["cyx"][i] * 175.126_836_986_4
if element == "shaft":
parameters["L"][i] = parameters["L"][i] * 0.0254
parameters["i_d"][i] = parameters["i_d"][i] * 0.0254
parameters["o_d"][i] = parameters["o_d"][i] * 0.0254
parameters["axial_force"][i] = (parameters["axial_force"][i] *
4.448_221_615_255)
elif element == "disk":
parameters["m"][i] = parameters["m"][i] * 0.453_592_37
parameters["Id"][i] = parameters["Id"][i] * 0.000_292_639_7
parameters["Ip"][i] = parameters["Ip"][i] * 0.000_292_639_7
if convert_to_rad_per_sec:
for i in range(0, df.shape[0]):
if element == "bearing":
parameters["w"][i] = parameters["w"][i] * 0.104_719_755_119_7
parameters.update(new_materials)
return parameters
def __init__(
self,
L,
i_d,
o_d,
material,
n=None,
axial_force=0,
torque=0,
shear_effects=True,
rotary_inertia=True,
gyroscopic=True,
shear_method_calc="cowper",
):
if type(material) is str:
os.chdir(Path(os.path.dirname(ross.__file__)))
self.material = Material.use_material(material)
else:
self.material = material
self.shear_effects = shear_effects
self.rotary_inertia = rotary_inertia
self.gyroscopic = gyroscopic
self.axial_force = axial_force
self.torque = torque
self._n = n
self.n_l = n
self.n_r = None
if n is not None:
self.n_r = n + 1
self.shear_method_calc = shear_method_calc
self.L = float(L)
# diameters
self.i_d = float(i_d)
self.o_d = float(o_d)
self.i_d_l = float(i_d)
self.o_d_l = float(o_d)
self.i_d_r = float(i_d)
self.o_d_r = float(o_d)
self.color = self.material.color
self.A = np.pi * (o_d**2 - i_d**2) / 4
self.volume = self.A * self.L
self.m = self.material.rho * self.volume
# Ie is the second moment of area of the cross section about
# the neutral plane Ie = pi*r**2/4
self.Ie = np.pi * (o_d**4 - i_d**4) / 64
phi = 0
# picking a method to calculate the shear coefficient
# List of avaible methods:
# hutchinson - kappa as per Hutchinson (2001)
# cowper - kappa as per Cowper (1996)
if shear_effects:
r = i_d / o_d
r2 = r * r
r12 = (1 + r2)**2
if shear_method_calc == "hutchinson":
# Shear coefficient (phi)
# kappa as per Hutchinson (2001)
# fmt: off
kappa = 6 * r12 * ((1 + self.material.Poisson) /
((r12 *
(7 + 12 * self.material.Poisson +
4 * self.material.Poisson**2) + 4 * r2 *
(5 + 6 * self.material.Poisson +
2 * self.material.Poisson**2))))
# fmt: on
elif shear_method_calc == "cowper":
# kappa as per Cowper (1996)
# fmt: off
kappa = 6 * r12 * ((1 + self.material.Poisson) /
(r12 *
(7 + 6 * self.material.Poisson) + r2 *
(20 + 12 * self.material.Poisson)))
# fmt: on
else:
raise Warning(
"This method of calculating shear coefficients is not implemented. See guide for futher informations."
)
# fmt: off
phi = 12 * self.material.E * self.Ie / (self.material.G_s * kappa *
self.A * L**2)
# fmt: on
self.phi = phi
def read_table_file(file, element, sheet_name=0, n=0, sheet_type="Model"):
"""Instantiate one or more element objects using inputs from an Excel table.
Parameters
----------
file: str
Path to the file containing the shaft parameters.
element: str
Specify the type of element to be instantiated: bearing, shaft or disk.
sheet_name: int or str, optional
Position of the sheet in the file (starting from 0) or its name. If none is passed, it is
assumed to be the first sheet in the file.
n: int
Exclusive for bearing elements, since this parameter is given outside the table file.
sheet_type: str
Exclusive for shaft elements, as they have a Model table in which more information can be passed,
such as the material parameters.
Returns
-------
A dictionary of parameters.
Examples
--------
>>> import os
>>> file_path = os.path.dirname(os.path.realpath(__file__)) + '/tests/data/shaft_si.xls'
>>> read_table_file(file_path, "shaft", sheet_type="Model", sheet_name="Model") # doctest: +ELLIPSIS
{'L': [0.03...
"""
df = pd.read_excel(file, header=None, sheet_name=sheet_name)
# Assign specific values to variables
parameter_columns = {}
optional_parameter_columns = {}
header_key_word = ''
default_dictionary = {}
parameters = {}
if element == 'bearing':
header_key_word = 'kxx'
parameter_columns['kxx'] = ['kxx']
parameter_columns['cxx'] = ['cxx']
optional_parameter_columns['kyy'] = ['kyy']
optional_parameter_columns['kxy'] = ['kxy']
optional_parameter_columns['kyx'] = ['kyx']
optional_parameter_columns['cyy'] = ['cyy']
optional_parameter_columns['cxy'] = ['cxy']
optional_parameter_columns['cyx'] = ['cyx']
optional_parameter_columns['w'] = ['w', 'speed']
default_dictionary['kyy'] = None
default_dictionary['kxy'] = 0
default_dictionary['kyx'] = 0
default_dictionary['cyy'] = None
default_dictionary['cxy'] = 0
default_dictionary['cyx'] = 0
default_dictionary['w'] = None
elif element == 'shaft':
if sheet_type == 'Model':
header_key_word = 'od_left'
else:
header_key_word = 'material'
parameter_columns['L'] = ['length']
parameter_columns['i_d'] = ['i_d', 'id', 'id_left']
parameter_columns['o_d'] = ['o_d', 'od', 'od_left']
parameter_columns['material'] = ['material', 'matnum']
optional_parameter_columns['n'] = ['n', 'elemnum']
optional_parameter_columns['axial_force'] = [
'axial_force', 'axial force', 'axial'
]
optional_parameter_columns['torque'] = ['torque']
optional_parameter_columns['shear_effects'] = [
'shear_effects', 'shear effects'
]
optional_parameter_columns['rotary_inertia'] = [
'rotary_inertia', 'rotary inertia'
]
optional_parameter_columns['gyroscopic'] = ['gyroscopic']
optional_parameter_columns['shear_method_calc'] = [
'shear_method_calc', 'shear method calc'
]
default_dictionary['n'] = None
default_dictionary['axial_force'] = 0
default_dictionary['torque'] = 0
default_dictionary['shear_effects'] = True
default_dictionary['rotary_inertia'] = True
default_dictionary['gyroscopic'] = True
default_dictionary['shear_method_calc'] = 'cowper'
elif element == 'disk':
header_key_word = 'ip'
parameter_columns['n'] = ['unnamed: 0', 'n']
parameter_columns['m'] = ['m', 'mass']
parameter_columns['Id'] = ['it', 'id']
parameter_columns['Ip'] = ['ip']
# Find table header and define if conversion is needed
header_index = -1
header_found = False
convert_to_metric = False
convert_to_rad_per_sec = False
for index, row in df.iterrows():
for i in range(0, row.size):
if isinstance(row[i], str):
if not header_found:
if row[i].lower() == header_key_word:
header_index = index
header_found = True
if 'inches' in row[i].lower() or 'lbm' in row[i].lower():
convert_to_metric = True
if 'rpm' in row[i].lower():
convert_to_rad_per_sec = True
if header_found and convert_to_metric and convert_to_rad_per_sec:
break
if header_found and convert_to_metric:
break
if not header_found:
raise ValueError(
"Could not find the header. Make sure the table has a header "
"containing the names of the columns. In the case of a " +
element + ", "
"there should be a column named " + header_key_word + ".")
# Get specific data from the file
new_materials = {}
if element == 'shaft' and sheet_type == 'Model':
material_header_index = -1
material_header_found = False
material_header_key_word = 'matno'
for index, row in df.iterrows():
for i in range(0, row.size):
if isinstance(row[i], str):
if row[i].lower() == material_header_key_word:
material_header_index = index
material_header_found = True
break
if material_header_found:
break
if not material_header_found:
raise ValueError(
"Could not find the header for the materials. Make sure the table has a header "
"with the parameters for the materials that will be used. There should be a column "
"named " + material_header_key_word + ".")
df_material = pd.read_excel(file,
header=material_header_index,
sheet_name=sheet_name)
material_name = []
material_rho = []
material_e = []
material_g_s = []
for index, row in df_material.iterrows():
if not pd.isna(row['matno']):
material_name.append(int(row['matno']))
material_rho.append(row['rhoa'])
material_e.append(row['ea'])
material_g_s.append(row['ga'])
else:
break
if convert_to_metric:
for i in range(0, len(material_name)):
material_rho[i] = material_rho[i] * 27679.904
material_e[i] = material_e[i] * 6894.757
material_g_s[i] = material_g_s[i] * 6894.757
for i in range(0, len(material_name)):
new_material = Material(
name='shaft_mat_' + str(material_name[i]),
rho=material_rho[i],
E=material_e[i],
G_s=material_g_s[i],
)
new_materials['shaft_mat_' + str(material_name[i])] = new_material
df = pd.read_excel(file, header=header_index, sheet_name=sheet_name)
df.columns = df.columns.str.lower()
# Find and isolate data rows
first_data_row_found = False
last_data_row_found = False
indexes_to_drop = []
for index, row in df.iterrows():
if not first_data_row_found \
and (isinstance(row[header_key_word], int) or isinstance(row[header_key_word], float)) \
and not pd.isna(row[header_key_word]):
first_data_row_found = True
elif not first_data_row_found:
indexes_to_drop.append(index)
elif first_data_row_found and not last_data_row_found:
if (isinstance(row[header_key_word], int) or isinstance(row[header_key_word], float))\
and not pd.isna(row[header_key_word]):
continue
else:
last_data_row_found = True
indexes_to_drop.append(index)
elif last_data_row_found:
indexes_to_drop.append(index)
if not first_data_row_found:
raise DataNotFoundError(
"Could not find the data. Make sure you have at least one row containing "
"data below the header.")
if len(indexes_to_drop) > 0:
df = df.drop(indexes_to_drop)
# Build parameters list
if element == 'bearing':
parameters['n'] = n
for key, value in parameter_columns.items():
for name in value:
try:
parameters[key] = df[name].tolist()
break
except KeyError:
if name == value[-1]:
raise ValueError(
"Could not find a column with one of these names: " +
str(value))
continue
for key, value in optional_parameter_columns.items():
for name in value:
try:
parameters[key] = df[name].tolist()
break
except KeyError:
if name == value[-1]:
parameters[key] = [default_dictionary[key]] * df.shape[0]
else:
continue
if element == 'shaft':
new_n = parameters['n']
for i in range(0, df.shape[0]):
new_n[i] -= 1
parameters['n'] = new_n
if sheet_type == 'Model':
new_material = parameters['material']
for i in range(0, df.shape[0]):
new_material[i] = 'shaft_mat_' + str(int(new_material[i]))
parameters['material'] = new_material
if convert_to_metric:
for i in range(0, df.shape[0]):
if element == 'bearing':
parameters['kxx'][i] = parameters['kxx'][i] * 175.1268369864
parameters['cxx'][i] = parameters['cxx'][i] * 175.1268369864
parameters['kyy'][i] = parameters['kyy'][i] * 175.1268369864
parameters['kxy'][i] = parameters['kxy'][i] * 175.1268369864
parameters['kyx'][i] = parameters['kyx'][i] * 175.1268369864
parameters['cyy'][i] = parameters['cyy'][i] * 175.1268369864
parameters['cxy'][i] = parameters['cxy'][i] * 175.1268369864
parameters['cyx'][i] = parameters['cyx'][i] * 175.1268369864
if element == 'shaft':
parameters['L'][i] = parameters['L'][i] * 0.0254
parameters['i_d'][i] = parameters['i_d'][i] * 0.0254
parameters['o_d'][i] = parameters['o_d'][i] * 0.0254
parameters['axial_force'][
i] = parameters['axial_force'][i] * 4.448221615255
elif element == 'disk':
parameters['m'][i] = parameters['m'][i] * 0.45359237
parameters['Id'][i] = parameters['Id'][i] * 0.0002926397
parameters['Ip'][i] = parameters['Ip'][i] * 0.0002926397
if convert_to_rad_per_sec:
for i in range(0, df.shape[0]):
if element == 'bearing':
parameters['w'][i] = parameters['w'][i] * 0.1047197551197
parameters.update(new_materials)
return parameters
def from_table(cls, file, sheet_type="Simple", sheet_name=0):
"""Instantiate one or more shafts using inputs from an Excel table.
A header with the names of the columns is required. These names should
match the names expected by the routine (usually the names of the
parameters, but also similar ones). The program will read every row
bellow the header until they end or it reaches a NaN.
Parameters
----------
file: str
Path to the file containing the shaft parameters.
sheet_type: str, optional
Describes the kind of sheet the function should expect:
Simple: The input table should specify only the number of the materials to be used.
They must be saved prior to calling the method.
Model: The materials parameters must be passed along with the shaft parameters. Each
material must have an id number and each shaft must reference one of the materials ids.
sheet_name: int or str, optional
Position of the sheet in the file (starting from 0) or its name. If none is passed, it is
assumed to be the first sheet in the file.
Returns
-------
shaft: list
A list of shaft objects.
"""
parameters = read_table_file(
file, "shaft", sheet_name=sheet_name, sheet_type=sheet_type
)
list_of_shafts = []
if sheet_type == "Model":
new_materials = {}
for i in range(0, len(parameters["matno"])):
new_material = Material(
name="shaft_mat_" + str(parameters["matno"][i]),
rho=parameters["rhoa"][i],
E=parameters["ea"][i],
G_s=parameters["ga"][i],
)
new_materials["shaft_mat_" + str(parameters["matno"][i])] = new_material
for i in range(0, len(parameters["L"])):
list_of_shafts.append(
cls(
L=parameters["L"][i],
idl=parameters["idl"][i],
odl=parameters["odl"][i],
idr=parameters["idr"][i],
odr=parameters["odr"][i],
material=new_materials[parameters["material"][i]],
n=parameters["n"][i],
axial_force=parameters["axial_force"][i],
torque=parameters["torque"][i],
shear_effects=parameters["shear_effects"][i],
rotary_inertia=parameters["rotary_inertia"][i],
gyroscopic=parameters["gyroscopic"][i],
shear_method_calc=parameters["shear_method_calc"][i],
)
)
elif sheet_type == "Simple":
for i in range(0, len(parameters["L"])):
list_of_shafts.append(
cls(
L=parameters["L"][i],
idl=parameters["idl"][i],
odl=parameters["odl"][i],
idr=parameters["idr"][i],
odr=parameters["odr"][i],
material=parameters["material"][i],
n=parameters["n"][i],
axial_force=parameters["axial_force"][i],
torque=parameters["torque"][i],
shear_effects=parameters["shear_effects"][i],
rotary_inertia=parameters["rotary_inertia"][i],
gyroscopic=parameters["gyroscopic"][i],
shear_method_calc=parameters["shear_method_calc"][i],
)
)
return list_of_shafts
def __init__(
self,
L,
idl,
odl,
idr=None,
odr=None,
material=None,
n=None,
axial_force=0,
torque=0,
shear_effects=True,
rotary_inertia=True,
gyroscopic=True,
shear_method_calc="cowper",
tag=None,
):
if idr is None:
idr = idl
if odr is None:
odr = odl
# After changing units to defined unit (see units.py), we go back to using only the magnitude
# This could be modified later if we apply pint to all arguments and have consistency throughout the package
L = L.m
idl = idl.m
odl = odl.m
idr = idr.m
odr = odr.m
if material is None:
raise AttributeError("Material is not defined.")
if type(material) is str:
os.chdir(Path(os.path.dirname(ross.__file__)))
self.material = Material.use_material(material)
else:
self.material = material
self.shear_effects = shear_effects
self.rotary_inertia = rotary_inertia
self.gyroscopic = gyroscopic
self.axial_force = axial_force
self.torque = torque
self._n = n
self.n_l = n
self.n_r = None
if n is not None:
self.n_r = n + 1
self.tag = tag
self.shear_method_calc = shear_method_calc
self.L = float(L)
self.o_d = (float(odl) + float(odr)) / 2
self.i_d = (float(idl) + float(idr)) / 2
self.idl = float(idl)
self.odl = float(odl)
self.idr = float(idr)
self.odr = float(odr)
self.color = self.material.color
# A_l = cross section area from the left side of the element
# A_r = cross section area from the right side of the element
A_l = np.pi * (odl ** 2 - idl ** 2) / 4
A_r = np.pi * (odr ** 2 - idr ** 2) / 4
self.A_l = A_l
self.A_r = A_r
# Second moment of area of the cross section from the left side
# of the element
Ie_l = np.pi * (odl ** 4 - idl ** 4) / 64
outer = self.odl ** 2 + self.odl * self.odr + self.odr ** 2
inner = self.idl ** 2 + self.idl * self.idr + self.idr ** 2
self.volume = np.pi * (self.L / 12) * (outer - inner)
self.m = self.material.rho * self.volume
roj = odl / 2
rij = idl / 2
rok = odr / 2
rik = idr / 2
# geometrical coefficients
delta_ro = rok - roj
delta_ri = rik - rij
a1 = 2 * np.pi * (roj * delta_ro - rij * delta_ri) / A_l
a2 = np.pi * (roj ** 3 * delta_ro - rij ** 3 * delta_ri) / Ie_l
b1 = np.pi * (delta_ro ** 2 - delta_ri ** 2) / A_l
b2 = (
3
* np.pi
* (roj ** 2 * delta_ro ** 2 - rij ** 2 * delta_ri ** 2)
/ (2 * Ie_l)
)
gama = np.pi * (roj * delta_ro ** 3 - rij * delta_ri ** 3) / Ie_l
delta = np.pi * (delta_ro ** 4 - delta_ri ** 4) / (4 * Ie_l)
self.a1 = a1
self.a2 = a2
self.b1 = b1
self.b2 = b2
self.gama = gama
self.delta = delta
# the area is calculated from the cross section located in the middle
# of the element
self.A = A_l * (1 + a1 * 0.5 + b1 * 0.5 ** 2)
# Ie is the second moment of area of the cross section - located in
# the middle of the element - about the neutral plane
Ie = Ie_l * (1 + a2 * 0.5 + b2 * 0.5 ** 2 + gama * 0.5 ** 3 + delta * 0.5 ** 4)
self.Ie = Ie
self.Ie_l = Ie_l
phi = 0
# geometric center
c1 = (
roj ** 2
+ 2 * roj * rok
+ 3 * rok ** 2
- rij ** 2
- 2 * rij * rik
- 3 * rik ** 2
)
c2 = (roj ** 2 + roj * rok + rok ** 2) - (rij ** 2 + rij * rik + rik ** 2)
self.beam_cg = L * c1 / (4 * c2)
self.axial_cg_pos = None
# Slenderness ratio of beam elements (G*A*L^2) / (E*I)
sld = (self.material.G_s * self.A * self.L ** 2) / (self.material.E * Ie)
self.slenderness_ratio = sld
# Moment of inertia
# fmt: off
self.Im = (
(np.pi * L * (self.m / self.volume) / 10) *
((roj ** 4 + roj ** 3 * rok + roj ** 2 * rok ** 2 + roj * rok ** 3 + rok ** 4) -
(rij ** 4 + rij ** 3 * rik + rij ** 2 * rik ** 2 + rij * rik ** 3 + rik ** 4))
)
# fmt: on
# picking a method to calculate the shear coefficient
# List of avaible methods:
# hutchinson - kappa as per Hutchinson (2001)
# cowper - kappa as per Cowper (1996)
if shear_effects:
r = ((idl + idr) / 2) / ((odl + odr) / 2)
r2 = r * r
r12 = (1 + r2) ** 2
if shear_method_calc == "hutchinson":
# Shear coefficient (phi)
# kappa as per Hutchinson (2001)
# fmt: off
kappa = 6 * r12 * ((1 + self.material.Poisson) /
((r12 * (7 + 12 * self.material.Poisson + 4 * self.material.Poisson ** 2) +
4 * r2 * (5 + 6 * self.material.Poisson + 2 * self.material.Poisson ** 2))))
# fmt: on
elif shear_method_calc == "cowper":
# kappa as per Cowper (1996)
# fmt: off
kappa = 6 * r12 * (
(1 + self.material.Poisson)
/ (r12 * (7 + 6 * self.material.Poisson) + r2 * (20 + 12 * self.material.Poisson))
)
# fmt: on
else:
raise Warning(
"This method of calculating shear coefficients is not implemented. See guide for futher informations."
)
# fmt: off
phi = 12 * self.material.E * self.Ie / (self.material.G_s * kappa * self.A * L ** 2)
# fmt: on
self.kappa = kappa
self.phi = phi
self.dof_global_index = None
def from_table(cls, file, sheet="Simple"):
"""Instantiate one or more shafts using inputs from a table, either excel or csv.
Parameters
----------
file: str
Path to the file containing the shaft parameters.
sheet: str, optional
Describes the kind of sheet the function should expect:
Simple: The input table should contain a header with column names equal
to parameter names in the ShaftElement class, except for
shear_effects, rotary_inertia, gyroscopic, and shear_method_calc.
Model: The sheet must follow the expected format. The function will look
for the parameters according to this format, in the positions they are supposed
to be found. Headers should be in rows 4 and 20, just before parameters.
Returns
-------
shaft : list
A list of shaft objects.
"""
if sheet == "Simple":
try:
df = pd.read_excel(file)
except FileNotFoundError:
sys.exit(file + " not found.")
except xlrd.biffh.XLRDError:
df = pd.read_csv(file)
try:
for index, row in df.iterrows():
for i in range(0, row.size):
if pd.isna(row[i]):
warnings.warn("NaN found in row " + str(index) +
" column " + str(i) + ".\n"
"It will be replaced with zero.")
row[i] = 0
list_of_shafts = []
for i, row in df.iterrows():
shear_effects = True
rotary_inertia = True
gyroscopic = True
shear_method_calc = "cowper"
try:
shear_effects = bool(row["shear_effects"])
except KeyError:
pass
try:
rotary_inertia = bool(row["rotary_inertia"])
except KeyError:
pass
try:
gyroscopic = bool(row["gyroscopic"])
except KeyError:
pass
try:
shear_method_calc = row["shear_method_calc"]
except KeyError:
pass
list_of_shafts.append(
cls(
row.L,
row.i_d,
row.o_d,
Material.use_material(row.material),
n=row.n,
axial_force=row.axial_force,
torque=row.torque,
shear_effects=shear_effects,
rotary_inertia=rotary_inertia,
gyroscopic=gyroscopic,
shear_method_calc=shear_method_calc,
))
return list_of_shafts
except KeyError:
sys.exit(
"One or more column names did not match the expected. "
"Make sure the table header contains the parameters for the "
"ShaftElement class. Also, make sure you have a material "
"with the given name.")
elif sheet == "Model":
try:
df1 = pd.read_excel(file, header=3, nrows=10)
df2 = pd.read_excel(file, header=19)
df_unit = pd.read_excel(file, header=16, nrows=2)
except FileNotFoundError:
sys.exit(file + " not found.")
except xlrd.biffh.XLRDError:
df1 = pd.read_csv(file, header=3, nrows=10)
df2 = pd.read_csv(file, header=19)
df_unit = pd.read_csv(file, header=16, nrows=2)
convert_to_metric = False
if df_unit["Length"][1] != "meters":
convert_to_metric = True
material_name = []
material_rho = []
material_e = []
material_g_s = []
new_materials = {}
for index, row in df1.iterrows():
if not pd.isna(row["matno"]):
material_name.append(int(row["matno"]))
material_rho.append(row["rhoa"])
material_e.append(row["ea"])
material_g_s.append(row["ga"])
if convert_to_metric:
for i in range(0, len(material_name)):
material_rho[i] = material_rho[i] * 27679.904
material_e[i] = material_e[i] * 6894.757
material_g_s[i] = material_g_s[i] * 6894.757
for i in range(0, len(material_name)):
new_material = Material(
name="shaft_mat_" + str(material_name[i]),
rho=material_rho[i],
E=material_e[i],
G_s=material_g_s[i],
)
new_materials["shaft_mat_" +
str(material_name[i])] = new_material
shaft_l = []
shaft_i_d = []
shaft_o_d = []
shaft_material = []
shaft_n = []
shaft_axial_force = []
for index, row in df2.iterrows():
shaft_l.append(row["length"])
shaft_i_d.append(row["id_Left"])
shaft_o_d.append(row["od_Left"])
shaft_material.append(int(row["matnum"]))
shaft_n.append(row["elemnum"] - 1)
shaft_axial_force.append(row["axial"])
if convert_to_metric:
for i in range(0, len(shaft_n)):
shaft_l[i] = shaft_l[i] * 0.0254
shaft_i_d[i] = shaft_i_d[i] * 0.0254
shaft_o_d[i] = shaft_o_d[i] * 0.0254
shaft_axial_force[i] = shaft_axial_force[i] * 4.448_221_61
list_of_shafts = []
for i in range(0, len(shaft_n)):
list_of_shafts.append(
cls(
shaft_l[i],
shaft_i_d[i],
shaft_o_d[i],
new_materials["shaft_mat_" + str(shaft_material[i])],
n=shaft_n[i],
axial_force=shaft_axial_force[i],
))
return list_of_shafts
else:
sys.exit(
"A valid choice must be given for the parameter 'sheet'. Either 'Simple' or 'Model' "
"were expected. It was given " + sheet + ".")