Plausibility Check
Never trust FEM results blindly — a systematic check before you use any result.
Never blindly trust an FEM result. A solver always produces output — but not necessarily correct output. Systematic plausibility checks are what separate reliable analyses from misleading ones.
What to check
- Deformation — does the direction and magnitude match your physical intuition?
- Force equilibrium — do reaction forces equal the applied loads? (∑F = 0 in all directions)
- Stress location — do peak stresses appear where you'd expect them mechanically?
- Symmetry — for a symmetric model with symmetric loading, are the results symmetric?
- Mesh sensitivity — do results change significantly when you refine the mesh?
- Unit consistency — are geometry (mm), forces (N), and material (MPa) all consistent?
Quick check
- Deformation in a realistic order of magnitude?
- Reaction forces = applied loads (∑F ≈ 0)?
- No unrealistic stress spikes at singularities in the assessment area?
When reaction forces don't match applied loads, a setup error is almost always the cause. Check load direction, load magnitude, and unit consistency first.
Why this matters
Incorrect inputs produce results that look physically plausible but are numerically wrong. A part under a 5000 N load with material entered in GPa instead of MPa will give deformations 1000× too small — and the contour plot will still look smooth and convincing.
Independent validation before using simulation data for engineering decisions is not optional — it's part of the analysis.