Visualization with Shear Center

[rhig2000]

What's the simplest way to visualize VABS outputs - shear center, tension center, CG, principle inertial and structural axes - in context with cross section geometry?

[unitasium]

You can try the SGIO python package: https://pypi.org/project/sgio/. To install: pip install -U sgio.

Then use the following script to create a plot:

import matplotlib.pyplot as plt
import sgio
from sgio.utils.plot import plot_sg_2d

fn = 'cs.dat'  # Your VABS input file name, relative path to this script or absolute path

cs = sgio.read(fn, 'vabs')  # Read VABS input
model = sgio.readOutputModel(f'{fn}.k', 'vabs', sg=cs)  # Read VABS output

fig, ax = plt.subplots()
plot_sg_2d(cs, model, ax)
plt.show()

This should show a plot like this:

This is the default plot. You can add more model elements manually (using the ax object and properties stored in model).

[rhig2000]

Thank you - this is helpful! The plot is exactly what I had hoped for. However, I have identified some opportunities for improvement...

1. sgio.read() may not be compatible with remarks contained within the VABS input file, such as those in isorect.sg
2. I'm not getting the beautiful mesh and my legend is askew: anisopipe shown below
   

[rhig2000]

It looks like plot_2d_mesh in sgio.utils.plot may need to be expanded to support other cell types such as quad8. It currently supports (3) cell types: triangle, triangle6, and quad.

[rhig2000]

This patch at line 151 does it!
elif cell_type == 'quad8': # Create polygons for quadrilaterals with 8 nodes for quad in cell_data: if quad is None: raise ValueError('A quad8 cell is None') if len(quad) != 8: raise ValueError('A quad8 cell must have 8 nodes') pts = mesh.points[quad[[0, 4, 1, 5, 2, 6, 3, 7]], 1:] polygon = plt.Polygon( pts, edgecolor=edge_color, facecolor=face_color, linewidth=line_width) patches.append(polygon)

I tweaked the legend, too. I'm satisfied!

[rhig2000]

Be advised: the sgio utility produces incorrect results when Vlasov is on. This can be demonstrated using isorect from the VABS install examples, and applying some basic transformations.

isorect.sg.txt

isorect_rotated_15degccw.sg.txt

isorect_rotated_15degccw_offset_x0.1_y0.3.sg.txt

isorect_rotated_15degccw_offset_x0.1_y0.3_vlasov.sg.txt