pyflange.bolts
The bolts
module contains objects representing the bolt, washer and nut
fastener components. In particular it contains
A
MetricBolt
class that generates generic bolts with metric screw thread and aStandardMetricBolt
function that generates MetricBolt objects with standard properties.A
FlatWasher
class that generates generic flat washer and aISOFlatWasher
frunction that returns aFlatWasher
with standard dimensions.A
HexNut
class that generates a generic hexagonal nut, aISOHExNut
function that generates aHexNut
with ISO 4032 dimensions`` and aRoundNut
function that generates a standard flangedHexNut
.
- class pyflange.bolts.BoltCrossSection(diameter: float)
- class pyflange.bolts.MetricBolt(nominal_diameter: float, thread_pitch: float, yield_stress: float, ultimate_tensile_stress: float, elastic_modulus: float = 210000000000.0, poissons_ratio: float = 0.3, shank_length: float = 0, shank_diameter_ratio: float = 1, stud: bool = False)
Generates a generic bolt with metric screw thread accoridng ISO 68-1, defined by the following parameters:
nominal_diameter
float
The outermost diameter of the screw thread.
thread_pitch
float
The pitch of the metric thread.
yield_stress
float
Nominal yield stress (0.2% strain limit) of the bolt material.
ultimate_tensile_stress
float
Nominal ultimate tensile stress of the bolt material.
elastic_modulus
float
[optional]The Young’s modulus of the bolt material. If omitted, it defaults to 210e9 N/m². Notice that the default value assumes that the chosen unit for distance is m and the chosen unit for forces is N. If that’s not the case, you should enter the proper value of this parameter.
poissons_ratio
float
[optional]The Poisson’s ratio of the bolt material. If omitted, it defaults to 0.30.
shank_length
float
[optional]The length of the shank. If omitted, it defaults to 0.
shank_diameter_ratio
float
[optional]The ratio between the shank diameter and the bolt nominal diameter. If omitted, it defaults to 1, which means that the shank hs the nominal diameter.
stud
bool
[optional]True if this is a stud bolt, False if it is not. If omitted, it defaults to False.
The parameters must be expressed in a consistent system of units. For example, if you chose to input distances in mm and forces in N, then stresses must be expressed in N/mm². All the bolt attributes and methods will return values consistently with the input units of measurement.
All the input parameters are also available as attributes of the generated object (e.g.
bolt.shank_length
,bolt.yield_stress
, etc.).This instances of this calss are designed to be immutable, which means than changing an attribute after creating an object is not a good idea. If you need a different bolt with different attributes, create a new one.
- property designation
Bolt designation string, which is, for example,
"M16"
for a bolt with nominal diameter 16 mm.
- property shank_diameter
Diameter of the shank.
- property thread_height
Height of the metric thread fundamental triangle (H), as defined in ISO 68-1:1998.
- property thread_basic_minor_diameter
Basic minor diameter (d1) as defined in ISO 68-1:1998.
- property thread_basic_pitch_diameter
Basic minor diameter (d2) as defined in ISO 68-1:1998.
- property thread_minor_diameter
Minor diameter (d3) as defined in ISO 898-1:2013.
- property nominal_cross_section
Bolt cross-section with nominal diameter
- property shank_cross_section
Bolt shank cross-section
- property thread_cross_section
Bolt cross-section used for tensile calculations
Ref. ISO 891-1:2013, section 9.1.6.1
- property shear_modulus
Shear modulus G, calculated from the Young’s modulus and Poisson’s ratio, under the assumption of isotropic and elastic bolt material.
- ultimate_tensile_capacity(standard='Eurocode')
Returns the design ultimate tensile force that the bolt can take, according to a given standard.
Currently the only standard available is “Eurocode”, which is also the default value of the
standard
parameter.
- axial_stiffness(length)
Given a clamped
length
, returns the axial stiffness of the bolt, according to VDI 2230, Part 1, Section 5.1.1.1.
- bending_stiffness(length)
Given a clamped
length
, returns the bending stiffness of the bolt, according to VDI 2230, Part 1, Section 5.1.1.2.
- property shank_cross_section_area
Area of the shank transversal cross-section.
DEPRECATED: use bolt.shank_cross_section.area instead
- property nominal_cross_section_area
Area of a circle with nominal diameter.
DEPRECATED: use bolt.nominal_cross_section.area instead
- property tensile_cross_section_area
Tensile stress area, according to ISO 891-1:2013, section 9.1.6.1
DEPRECATED: use bolt.thread_cross_section.area instead
- property tensile_moment_of_resistance
Tensile moment of resistance, according to ISO 891-1:2013, section 9.1.6.1
DEPRECATED: use bolt.thread_cross_section.elastic_section_modulus instead
- pyflange.bolts.StandardMetricBolt(designation, material_grade, shank_length=0.0, shank_diameter_ratio=1.0, stud=False)
This function provides a convenient way for creating
MetricBolt
object, given the standard geometry designation (e.g. “M20”) and the standard material grade designation (e.g. “8.8”).The required parameters are:
designation
str
The metric screw thread designation. The allowed values are: ‘M4’, ‘M5’, ‘M6’, ‘M8’, ‘M10’, ‘M12’, ‘M14’, ‘M16’, ‘M18’, ‘M20’, ‘M22’, ‘M24’, ‘M27’, ‘M30’, ‘M33’, ‘M36’, ‘M39’, ‘M42’, ‘M45’, ‘M48’, ‘M52’, ‘M56’, ‘M60’, ‘M64’, ‘M72’, ‘M80’, ‘M90’, ‘M100’.
This parameter corresponds to a standard nominal diameter and a relevant thread pitch value (i.e. the standard coarse pitch value).
material_grade
str
The material grade designation. The allowed values are: ‘4.6’, ‘4.8’, ‘5.6’, ‘5.8’, ‘6.8’, ‘8.8’, ‘9.8’, ‘10.9’ and ‘12.9’ for carbon-steel bolts; ‘A50’, ‘A70’, ‘A80’ and ‘A100’ for austenitic bolts; ‘D70’, ‘D80’ and ‘D100’ for duplex bolts; ‘C50’, ‘C70’, ‘C80’ and ‘C110’ for martensitic bolts; ‘F45’ and ‘F60’ for ferritic bolts.
This parameter corresponds to a standard set of the paraters
yield_stress
,ultimate_tensile_stress
,elastic_modulus
andpoissons_ratio
.
shank_length
float
[optional]The length of the shank. If omitted, it defaults to 0.
shank_diameter_ratio
float
[optional]The ratio between the shank diameter and the bolt nominal diameter. If omitted, it defaults to 1, which means that the shank hs the nominal diameter.
stud
bool
[optional]True if this is a stud bolt, False if it is not. If omitted, it defaults to False.
- class pyflange.bolts.FlatWasher(outer_diameter: float, inner_diameter: float, thickness: float, elastic_modulus: float = 210000000000.0, poissons_ratio: float = 0.3)
Generates a generic flat washer.
outer_diameter
float
The outer diameter of the washer.
inner_diameter
float
The hole diameter of the washer.
elastic_modulus
float
[optional]The Young’s modulus of the washer material. If omitted, it defaults to 210e9 N/m². Notice that the default value assumes that the chosen unit for distance is m and the chosen unit for forces is N. If that’s not the case, you should enter the proper value of this parameter.
poissons_ratio
float
[optional]The Poisson’s ratio of the washer material. If omitted, it defaults to 0.30.
The parameters must be expressed in a consistent system of units. For example, if you chose to input distances in mm and forces in N, then stresses must be expressed in N/mm². All the bolt attributes and methods will return values consistently with the input units of measurement.
All the input parameters are also available as attributes of the generated object (e.g.
washer.thickness
,washer.poissons_ratio
, etc.).This instances of this calss are designed to be immutable, which means than changing an attribute after creating an object is not a good idea. If you need a different washer with different attributes, create a new one.
- property area
Area of the washer flat surface
- property axial_stiffness
The compressive stiffness of the washer: t / EA
- pyflange.bolts.ISOFlatWasher(designation)
Standard washer according to ISO 7089
Returns a washer having the standard dimensions defined in ISO 7089, given the corresponding metric bolt designation.
For example,
ISOFlatWasher("M16")
will return aFlatWasher
instance with outer diameter 30 mm, hole diameter 17 mm and thickness 3 mm.
- class pyflange.bolts.HexNut(nominal_diameter: float, thickness: float, inscribed_diameter: float, circumscribed_diameter: float, bearing_diameter: float, elastic_modulus: float = 210000000000.0, poissons_ratio: float = 0.3)
Generates a generic flat washer.
nominal_diameter
float
The nominal diameter of the inner thread.
thickness
float
The height of the bolt.
inscribed_diameter
float
The diameter of the circle inscribed in the hexagon. Correponds to the distance between two opposite flats.
circumscribed_diameter
float
The diameter of the circle circumscribed in the hexagon. Correponds to the distance between two opposite vertices..
bearing_diameter
gloat
The outer diameter of the circular contatact surface between nut and washer.
elastic_modulus
float
[optional]The Young’s modulus of the nut material. If omitted, it defaults to 210e9 N/m². Notice that the default value assumes that the chosen unit for distance is m and the chosen unit for forces is N. If that’s not the case, you should enter the proper value of this parameter.
poissons_ratio
float
[optional]The Poisson’s ratio of the nut material. If omitted, it defaults to 0.30.
The parameters must be expressed in a consistent system of units. For example, if you chose to input distances in mm and forces in N, then stresses must be expressed in N/mm². All the bolt attributes and methods will return values consistently with the input units of measurement.
All the input parameters are also available as attributes of the generated object (e.g.
washer.thickness
,washer.poissons_ratio
, etc.).This instances of this calss are designed to be immutable, which means than changing an attribute after creating an object is not a good idea. If you need a different nut with different attributes, create a new one.
- pyflange.bolts.ISOHexNut(designation)
Standard Hex Nut
Returns an ISO 4032 HexNut, given the metric designation. For example:
nut = ISOHexNut('M16')
- pyflange.bolts.RoundNut(designation)
Standard Hex Nut
Returns a Standard Flanged HexNut, given the metric designation. For example:
nut = RoundNut('M42')