BeamDeflect is a small desktop application that computes and visualises the deflection, bending moment, and shear force of a prismatic beam under user-defined loads and supports. It is aimed at structural and mechanical engineering students, junior practitioners, and educators who want a quick, verifiable sanity check on a beam problem without firing up a full FEA package — enter the geometry, section, material, supports, and loads in a Tkinter form, click Calculate, and read the diagrams and headline numbers off the right-hand panel.
- Python 3.10+
- Install the Python dependencies:
pip install -r requirements.txt
- On Fedora Linux, install the system Tk packages that ship Tkinter and
its image support (these are not pip-installable):
On other distributions the equivalent packages are typically
sudo dnf install python3-tkinter python3-pillow-tk
python3-tk(Debian/Ubuntu),tk(Arch), orpython-tk(macOS Homebrew). Tkinter is bundled with the official python.org installers on Windows and macOS.
From the project root:
python main.py| Configuration | Left support | Right support |
|---|---|---|
| Simply supported | Pinned | Roller |
| Cantilever | Fixed | (free end) |
| Fixed-fixed | Fixed | Fixed |
- Point loads — any number, applied at any position along the beam (magnitude in kN, position in m).
- Uniformly distributed load (UDL) — a single full-span UDL (intensity in kN/m).
For every Calculate run, the right-hand panel shows:
- Deflection curve δ(x) in millimetres (downward-positive, plotted so the curve visually dips below the axis).
- Bending moment diagram (BMD) M(x) in kN·m (sagging-positive).
- Shear force diagram (SFD) V(x) in kN.
- Maximum deflection in mm.
- Maximum bending stress σmax = Mmax·c / I in MPa, with c = h/2 for the rectangular section.
All closed-form beam formulas used by the engine — reactions, shear, bending moment, and deflection — are sourced from:
Young, W. C. & Budynas, R. G., Roark's Formulas for Stress and Strain, 7th ed., McGraw-Hill, 2002.
Every formula in beam/calculator.py carries an inline comment citing
the specific Roark table or equation it implements (for example
# Roark Table 8.1, Case 1e (simply supported, intermediate concentrated load)),
so any computed result can be independently verified against the published
handbook. The test suite in tests/test_calculator.py re-evaluates those
same formulas symbolically and asserts that the engine matches them within
tight tolerance.
pip install pytest
python -m pytestIssues and pull requests are welcome via GitHub. Please open an issue first for anything larger than a small bug fix or doc change so we can discuss the direction before you sink time into a patch.
Released under the MIT License — see LICENSE.