'''
This module provides the core class and functions for representing and calculating the main
geometric and material properties of pipeline sections.
**Features:**
- The `Pipe` class encapsulates the geometry and material characteristics of a pipeline section,
supporting both scalar and array-based calculations for batch processing.
- Methods for computing inner/outer diameters, areas, steel and coating cross-sections, stiffness,
and moments of inertia.
- Designed for use in subsea pipeline and riser engineering, but general enough for any pipeline
property calculations.
All calculations are vectorized using NumPy for efficiency and flexibility.
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'''
import numpy as np
[docs]
class Pipe: # pylint: disable=too-many-arguments
"""
Class representing a pipeline section with geometric and material properties.
Supports both scalar and array inputs for calculations.
Parameters
----------
outer_diameter : float or array-like, optional
Outer diameter of the pipe (m). Default is 0.
wall_thickness : float or array-like, optional
Wall thickness of the pipe (m). Default is 0.
coating_thickness : float or array-like, optional
Coating wall thickness (m). Default is 0.
corrosion_allowance : float or array-like, optional
Corrosion allowance (m). Default is 0.
youngs_modulus : float or array-like, optional
Young's modulus of the material (Pa). Default is 0.
"""
def __init__(
self,
*,
outer_diameter=0.0,
wall_thickness=0.0,
coating_thickness=0.0,
corrosion_allowance=0.0,
youngs_modulus=0.0
):
"""
Initialize a Pipe object with geometric and material properties.
"""
self.outer_diameter = np.asarray(outer_diameter, dtype = float)
self.wall_thickness = np.asarray(wall_thickness, dtype = float)
self.coating_thickness = np.asarray(coating_thickness, dtype = float)
self.corrosion_allowance = np.asarray(corrosion_allowance, dtype = float)
self.youngs_modulus = np.asarray(youngs_modulus, dtype = float)
[docs]
def wall_thickness_corroded(self):
"""
Calculate the corroded wall thickness.
Returns
-------
corroded_wall_thickness : np.ndarray
Corroded wall thickness of the pipe.
Examples
--------
>>> wall_thickness = [0.0127, 0.0159]
>>> corrosion_allowance = [0.003, 0.003]
>>> pipe = Pipe(
... wall_thickness=wall_thickness,
... corrosion_allowance=corrosion_allowance
... )
>>> pipe.wall_thickness_corroded()
array([0.0097, 0.0129])
"""
return self.wall_thickness - self.corrosion_allowance
[docs]
def inner_diameter(self):
"""
Calculate the pipe inner diameter.
Returns
-------
inner_diameter : np.ndarray
Inner diameter of the pipe.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> wall_thickness = [0.0127, 0.0159]
>>> pipe = Pipe(
... outer_diameter=outer_diameter,
... wall_thickness=wall_thickness
... )
>>> pipe.inner_diameter()
array([0.2477, 0.2921])
"""
return self.outer_diameter - 2.0 * self.wall_thickness
[docs]
def inner_area(self):
"""
Calculate the pipe inner area.
Returns
-------
inner_area : np.ndarray
Inner area of the pipe.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> wall_thickness = [0.0127, 0.0159]
>>> pipe = Pipe(
... outer_diameter=outer_diameter,
... wall_thickness=wall_thickness
... )
>>> pipe.inner_area()
array([0.04818833, 0.06701206])
"""
return np.pi / 4.0 * self.inner_diameter() ** 2
[docs]
def outer_area(self):
"""
Calculate the pipe outer area.
Returns
-------
outer_area : np.ndarray
Outer area of the pipe.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> pipe = Pipe(
... outer_diameter=outer_diameter
... )
>>> pipe.outer_area()
array([0.05857783, 0.08239707])
"""
return np.pi / 4.0 * self.outer_diameter ** 2
[docs]
def steel_area(self):
"""
Calculate the steel cross-sectional area.
Returns
-------
steel_area : np.ndarray
Steel cross-sectional area.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> wall_thickness = [0.0127, 0.0159]
>>> pipe = Pipe(
... outer_diameter=outer_diameter,
... wall_thickness=wall_thickness
... )
>>> pipe.steel_area()
array([0.0103895 , 0.01538501])
"""
return self.outer_area() - self.inner_area()
[docs]
def total_outer_diameter(self):
"""
Calculate the total outer diameter of steel and coating.
Returns
-------
total_outer_diameter : np.ndarray
Total outer diameter of steel and coating.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> coating_thickness = [0.003, 0.003]
>>> pipe = Pipe(
... outer_diameter=outer_diameter,
... coating_thickness=coating_thickness
... )
>>> pipe.total_outer_diameter()
array([0.2791, 0.3299])
"""
return self.outer_diameter + 2.0 * self.coating_thickness
[docs]
def total_outer_area(self):
"""
Calculate the outer area of steel and coating.
Returns
-------
total_outer_area : np.ndarray
Outer area of steel and coating.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> coating_thickness = [0.003, 0.003]
>>> pipe = Pipe(
... outer_diameter=outer_diameter,
... coating_thickness=coating_thickness
... )
>>> pipe.total_outer_area()
array([0.06118001, 0.08547803])
"""
return np.pi / 4.0 * self.total_outer_diameter() ** 2
[docs]
def coating_area(self):
"""
Calculate the coating cross-sectional area.
Returns
-------
coating_area : np.ndarray
Coating cross-sectional area.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> coating_thickness = [0.003, 0.003]
>>> pipe = Pipe(
... outer_diameter=outer_diameter,
... coating_thickness=coating_thickness
... )
>>> pipe.coating_area()
array([0.00260218, 0.00308096])
"""
return self.total_outer_area() - self.outer_area()
[docs]
def axial_stiffness(self):
"""
Calculate the axial stiffness.
Returns
-------
axial_stiffness : np.ndarray
Axial stiffness of the pipe.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> wall_thickness = [0.0127, 0.0159]
>>> youngs_modulus = [207.0e+09, 207.0e+09]
>>> pipe = Pipe(
... outer_diameter=outer_diameter,
... wall_thickness=wall_thickness,
... youngs_modulus=youngs_modulus
... )
>>> pipe.axial_stiffness()
array([2.15062613e+09, 3.18469656e+09])
"""
return self.youngs_modulus * self.steel_area()
[docs]
def area_moment_inertia(self):
"""
Calculate the area moment inertia.
Returns
-------
area_moment_inertia : np.ndarray
Area moment inertia.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> wall_thickness = [0.0127, 0.0159]
>>> pipe = Pipe(
... outer_diameter=outer_diameter,
... wall_thickness=wall_thickness
... )
>>> pipe.area_moment_inertia()
array([8.82710601e-05, 1.82921605e-04])
"""
return np.pi / 64.0 * (self.outer_diameter ** 4 - self.inner_diameter() ** 4)
[docs]
def bending_stiffness(self):
"""
Calculate the bending stiffness.
Returns
-------
bending_stiffness : np.ndarray
Bending stiffness.
Examples
--------
>>> outer_diameter = [0.2731, 0.3239]
>>> wall_thickness = [0.0127, 0.0159]
>>> youngs_modulus = [207.0e+09, 207.0e+09]
>>> pipe = Pipe(
... outer_diameter=outer_diameter,
... wall_thickness=wall_thickness,
... youngs_modulus=youngs_modulus
... )
>>> pipe.bending_stiffness()
array([18272109.437121..., 37864772.21769765])
"""
return self.youngs_modulus * self.area_moment_inertia()
