Unable to calculate stress in a shape under loading.

[EngDM]

I am having issues following the guide @ https://sectionproperties.readthedocs.io/en/stable/examples/analysis/stress_analysis.html

When I attempt to run a stress analysis it does not recognize mxx as an input.

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Input In [31], in <cell line: 1>()
----> 1 loading = analysis_sec.calculate_stress(mxx=10)

TypeError: calculate_stress() got an unexpected keyword argument 'mxx'

Code for replication:

from sectionproperties.pre.geometry import Geometry, CompoundGeometry
from sectionproperties.analysis.section import Section
from sectionproperties.pre.library.steel_sections import i_section
from sectionproperties.pre.library.steel_sections import angle_section
from sectionproperties.pre.library.primitive_sections import circular_section
from sectionproperties.pre.library.steel_sections import tapered_flange_channel
from sectionproperties.pre.pre import Material
import sectionproperties.pre.geometry
import easygui
import math as math

#W-Shape Dimenions
Fy = 345#float(easygui.enterbox('Enter Yield Strength Fy (MPa) = '))
d = 537#float(easygui.enterbox('Enter Depth of W-Shape d (mm) = '))
b = 210#float(easygui.enterbox('Enter Width of W-Shape b (mm) = '))
t_f = 17.4#float(easygui.enterbox('Enter flange thickness t (mm) = '))
t_w = 10.9#float(easygui.enterbox('Enter web thickness w (mm) = '))
r = 11.4#float(easygui.enterbox('Enter fillet radius r (mm) = '))
n_r = 8
#Channel Dimensions
cd=381
cb=86
ct_f=16.5
ct_w=10.2
cr_r=0
cr_f=0
calpha=9.46
cn_r=0

#W-Shape Definition
geom = i_section(d=d, b=b, t_f=t_f, t_w=t_w, r=r, n_r=n_r)
#Channel Definition
geom2 = tapered_flange_channel(d=cd, b=cb, t_f=ct_f, t_w=ct_w, r_r=cr_r, r_f=cr_f, alpha=calpha, n_r=cn_r).rotate_section(angle=-90).align_center(align_to=geom).align_to(other=geom, on="top").shift_section(y_offset=(ct_w-cb))

#Shape Processing
reinforced = geom+geom2
reinforced.plot_geometry()
#Property Processing
reinforced.create_mesh(mesh_sizes=[10])
analysis_sec = Section(geometry=reinforced)
analysis_sec.plot_mesh()
analysis_sec.calculate_geometric_properties()
analysis_sec.calculate_plastic_properties()
analysis_sec.calculate_warping_properties()
analysis_sec.plot_centroids()
#Calculate Properties Table
analysis_sec.display_results(fmt='.4f')

loading = analysis_sec.calculate_stress(mxx=800e6)

As an aside, I'm trying to find a reliable way to calculate the depth of web in compression to be able to calculate the rt value, and subsequently the moment resistance of an unsymetric shape (channel-capped I beam), shapes typically used for crane support systems.

[robbievanleeuwen]

Hi @EngDM, can you confirm you are running the latest version of sectionproperties? In v2 a bending moment about the x-axis was passed to calculate_stress with Mxx=, however since v3, this has been changed to mxx= to conform to the python style guide (release notes here - under breaking changes "Pythonic renaming of methods and variables...").

[EngDM]

Hi @EngDM, can you confirm you are running the latest version of sectionproperties? In v2 a bending moment about the x-axis was passed to calculate_stress with Mxx=, however since v3, this has been changed to mxx= to conform to the python style guide (release notes here - under breaking changes "Pythonic renaming of methods and variables...").

Hi @robbievanleeuwen

It appears that I am still on version 2.1.0. I have since updated to 3.2.2, but now I cannot re-launch my ipynb files in Jupyter Desktop. I get

Edit: I re-installed jupyter and it now opens correctly.

Further, before I closed the file to re-open it appear that it broke a lot of my imports. Some of the errors I think were just how sectionproperties changed how it imports, putting everything into a single shape library, but I also had errors with "numba" whatever that is.

Edit:
Here is the code (I don't think the imports commented out are the problem):

from sectionproperties.pre import Geometry, CompoundGeometry
from sectionproperties.analysis.section import Section
from sectionproperties.library import i_section
from sectionproperties.library import angle_section
from sectionproperties.library import circular_section
from sectionproperties.library import tapered_flange_channel
from sectionproperties import Material
import sectionproperties.pre.geometry
'''
import easygui
import math as math
import handcalcs.render
import forallpeople
forallpeople.environment('structural', top_level=True)
from scipy.optimize import fsolve
'''

Here is the error:

---------------------------------------------------------------------------
SystemError                               Traceback (most recent call last)
Input In [4], in <cell line: 1>()
----> 1 from sectionproperties.pre import Geometry, CompoundGeometry
      2 from sectionproperties.analysis import Section
      3 from sectionproperties.pre.library import i_section

File ~\anaconda3\lib\site-packages\sectionproperties\pre\__init__.py:3, in <module>
      1 """sectionproperties pre-processor."""
----> 3 from sectionproperties.pre.geometry import CompoundGeometry, Geometry
      4 from sectionproperties.pre.pre import Material

File ~\anaconda3\lib\site-packages\sectionproperties\pre\geometry.py:25, in <module>
     13 from shapely import (
     14     GeometryCollection,
     15     LinearRing,
   (...)
     21     box,
     22 )
     23 from shapely.ops import split, unary_union
---> 25 import sectionproperties.post.post as post
     26 import sectionproperties.pre.bisect_section as bisect
     27 import sectionproperties.pre.pre as pre

File ~\anaconda3\lib\site-packages\sectionproperties\post\post.py:16, in <module>
     13 from rich.console import Console
     14 from rich.table import Table
---> 16 import sectionproperties.analysis.fea as fea
     19 if TYPE_CHECKING:
     20     import matplotlib.axes

File ~\anaconda3\lib\site-packages\sectionproperties\analysis\__init__.py:3, in <module>
      1 """sectionproperties analysis module."""
----> 3 from sectionproperties.analysis.section import Section

File ~\anaconda3\lib\site-packages\sectionproperties\analysis\section.py:27, in <module>
     24 from shapely import Point, Polygon
     25 from shapely.strtree import STRtree
---> 27 import sectionproperties.analysis.fea as fea
     28 import sectionproperties.analysis.plastic_section as sp_plastic
     29 import sectionproperties.analysis.solver as solver

File ~\anaconda3\lib\site-packages\sectionproperties\analysis\fea.py:24, in <module>
     22 # numba is an optional dependency
     23 try:
---> 24     from numba import njit
     25 except ImportError:
     27     def njit(**options: Any) -> Callable[[Any], Any]:

File ~\anaconda3\lib\site-packages\numba\__init__.py:42, in <module>
     38 from numba.core.decorators import (cfunc, generated_jit, jit, njit, stencil,
     39                                    jit_module)
     41 # Re-export vectorize decorators and the thread layer querying function
---> 42 from numba.np.ufunc import (vectorize, guvectorize, threading_layer,
     43                             get_num_threads, set_num_threads)
     45 # Re-export Numpy helpers
     46 from numba.np.numpy_support import carray, farray, from_dtype

File ~\anaconda3\lib\site-packages\numba\np\ufunc\__init__.py:3, in <module>
      1 # -*- coding: utf-8 -*-
----> 3 from numba.np.ufunc.decorators import Vectorize, GUVectorize, vectorize, guvectorize
      4 from numba.np.ufunc._internal import PyUFunc_None, PyUFunc_Zero, PyUFunc_One
      5 from numba.np.ufunc import _internal, array_exprs

File ~\anaconda3\lib\site-packages\numba\np\ufunc\decorators.py:3, in <module>
      1 import inspect
----> 3 from numba.np.ufunc import _internal
      4 from numba.np.ufunc.parallel import ParallelUFuncBuilder, ParallelGUFuncBuilder
      6 from numba.core.registry import DelayedRegistry

SystemError: initialization of _internal failed without raising an exception

[EngDM]

Downgraded to version 3.0.1 of sectionproperties and it is working again.

[robbievanleeuwen]

Looks like an issue with your numba installation which is shipped with anaconda (which it looks like you are using). numba was introduced to speed up computations in v3.1.0. In version post this release, if numba is installed, sectionproperties tries to use it - I suspect this is what is causing the errors.

I don't use anaconda but after a quick google it looks like you can create a fresh environment (without the default included numba) with conda create --name myenv python=3.12 --no-default-packages (using whatever python version you'd like). You can then try pip install sectionproperties into this fresh environment.