5 Common Mistakes to Avoid in FEA & CFD Simulation

Simulation18 March 2026·By The Sarjan Solution Team

Simulation is only as good as the assumptions behind it. A beautifully meshed model with the wrong boundary condition will still hand you a wrong answer — just with more decimal places of confidence. After running FEA and CFD studies across machinery, elevator components and switchgear enclosures, the same handful of mistakes show up again and again. Here are five worth checking before you trust a result.

1. Treating The Mesh As "Good Enough" Without A Convergence Check

A common shortcut is meshing once, solving once, and moving on. Without a mesh convergence study — refining the mesh and re-running until results stop changing significantly — you can't actually tell whether your stress or flow result is accurate, or just a mesh-density artefact.

2. Oversimplifying Boundary Conditions

A rigid fixed support is easy to define and rarely exists in the real world. Bolted joints have compliance, bearings allow rotation, and welded connections aren't perfectly rigid either. Boundary conditions that are simpler than reality tend to produce stress concentrations that don't match how the part actually fails — or doesn't fail — in service.

3. Ignoring Load Case Combinations

Static analysis under a single peak load is a starting point, not the full picture. Fatigue-critical components need cyclic loading considered; equipment with startup transients needs those transients checked, not just steady-state operation. Skipping combined or repeated load cases is one of the fastest ways to miss a real failure mode.

4. Running CFD Without Validating Against Something Physical

CFD is powerful, but it's a numerical approximation of turbulence models that are themselves approximations. Where possible, anchor a CFD result against a known data point — a manufacturer's flow curve, a physical test, or even a hand-calculated pressure drop for a simplified case — before trusting the model for a design decision.

5. Reporting A Number Without An Engineering Recommendation

A factor-of-safety number on its own doesn't help a design team decide what to do next. The most useful simulation reports pair the result with a clear recommendation — reduce thickness here, add a rib there, or confirm the design as-is — so the study actually moves the project forward.

The Takeaway

None of these mistakes are exotic — they're process gaps. Building a mesh-convergence check, a boundary-condition review and a validation step into every simulation engagement is what turns an FEA or CFD report from a nice-looking colour plot into something a design team can actually act on.