Test fixture crosshead

Implementation

Quadratic triangular finite elements with distributed loads and spring supports.

Centered and eccentric 500 N cases across three support stiffnesses.

CAD exports and a dimensioned drawing for the selected windowed reference geometry.

Completed 20000 bounded input combinations, a calibrated compliance model, reduced-order out-of-plane torsion screening and 33 synthetic load-cycle readings.

The final installation envelope specifies 30 MN/m vertical and 500 N m/rad rotational stiffness per support; weak mounts and larger offsets remain rejected cases.

Inputs and assumptions

• 6061-type reference elastic properties: E 69 GPa, nu 0.33; constant 20 mm thickness.
• Declared support stiffnesses are sensitivity inputs, not measured hardware.

Results

Report figures (2)

Open the full report ↗

Verification

43 executed checks pass; regression tests and invalid-input checks are recorded separately. 11 commissioning acceptance checks and 7 additional regressions pass. The selected combined translational/torsional envelope stays below 0.05 mm including a 0.0001 mm response-fit allowance.

python run.py && python test_project.py && python complete_validation.py && python test_completion.py

Project files

The ZIP contains the source, inputs, results, and instructions. These files are also available individually.

• Finite element solversolver.py · 5 KB
• Geometry and load inputsinputs.json · 1 KB
• All load casesoutputs/load-cases.csv · 4 KB
• Mesh convergenceoutputs/mesh-convergence.csv · 2 KB
• Selected CAD modeloutputs/cad/window_12mm.step · 41 KB
• Dimensioned reference drawingoutputs/selected-drawing.svg · 44 KB
• Structural reportreport.html · 7 KB
• Accepted combined installation envelopecompletion/selected-operating-envelope.csv · 1 KB
• 20000 synthetic combinationscompletion/synthetic-envelope.csv · 2.1 MB
• Out-of-plane torque and mount sensitivitycompletion/out-of-plane-screen.csv · 1 KB
• Executed commissioning and fault studycompletion/report.html · 13 KB
• Completion acceptance matrix and source hashescompletion.json · 6 KB
• Reproduce the commissioning studycomplete_validation.py · 14 KB
• Declared commissioning inputscompletion-inputs.json · 1 KB

Run locally

Python 3.12 / scikit-fem 12.0.2 / SciPy 1.17.0 / NumPy 2.3.5 / CadQuery 2.7.0 / Matplotlib 3.10.8

Extract the ZIP and open a terminal in the test-fixture-crosshead folder. The README includes setup and usage details.

python -m pip install -r requirements.txt
python run.py
python test_project.py
python complete_validation.py
python test_completion.py

Limits

• Primary FEA is 2D plane stress with constant nominal 20 mm thickness. A separate reduced-order torsion screen evaluates through-thickness load offset; it does not resolve 3D joints or contact.
• The selected support stiffnesses are required model inputs, not measured hardware properties. The accepted envelope and rejected support cases are both documented.
• Ideal sharp-window corners are excluded from reported finite stress. Declared stress multipliers do not establish notch fatigue strength or a load rating.
• Synthetic input distributions and load-cell readings test analysis/data-reduction behavior. They are not manufacturing capability or physical FEA correlation.