Plot Cross-Section with Beam Properties#

Problem Description#

This example demonstrates how to visualize a VABS cross-section geometry with beam properties overlay using SGIO.

Solution#

"""Example: Plot Cross-Section with Beam Properties

This example demonstrates how to:
1. Read a VABS cross-section input file
2. Read the corresponding VABS output (beam properties)
3. Visualize the cross-section with property overlay

The plot shows the cross-section geometry with beam properties like
neutral axis, shear center, and principal axes.
"""
import matplotlib.pyplot as plt
import sgio
from sgio import plot_sg_2d, plot_model_2d, plot_matrix, plot_matrix_bar3d

input_file = 'sg21eb_tri3_vabs40.sg'
output_file = 'sg21eb_tri3_vabs40.sg.K'

# Read VABS output (beam properties)
model = sgio.read_output_model(output_file, 'vabs', model_type='BM1')

# Read VABS input (cross-section mesh)
cs = sgio.read(input_file, 'vabs')

# Create plot

# Create figure and axis
fig, ax = plt.subplots(figsize=(10, 8))

# Plot cross-section geometry, then overlay the beam properties
plot_sg_2d(cs, ax)
plot_model_2d(model, ax)

# Add labels
ax.set_xlabel(r'$x_2$ (m)', fontsize=12)
ax.set_ylabel(r'$x_3$ (m)', fontsize=12)
ax.grid(True, alpha=0.3)
ax.set_aspect('equal')

# Display the plot
plt.tight_layout()
fig.savefig('sg21eb_tri3_vabs40.png', dpi=300)
# print("\nDisplaying plot... (close window to exit)")
# plt.show()
plt.close(fig)


# Plot stiffness matrix
stf_matrix = model.stff

fig2, ax2 = plt.subplots(figsize=(8, 6))
plot_matrix(
    stf_matrix, fig=fig2, ax=ax2,
    annotate=True, font_size=8, symlog=True
    )
fig2.savefig('stiffness_matrix.png', dpi=300)
plt.close(fig2)

fig3 = plt.figure(figsize=(8, 6))
ax3 = fig3.add_subplot(projection='3d')
plot_matrix_bar3d(
    stf_matrix, fig=fig3, ax=ax3,
    symlog=True
    )
fig3.savefig('stiffness_matrix_3d.png', dpi=300)
plt.close(fig3)

Result#

The script displays a matplotlib window showing the cross-section geometry with:

  • The mesh visualization

  • Neutral axis

  • Shear center

  • Principal axes

../_images/sg21eb_tri3_vabs40.png

File List#