Your values (everyday units)
Poisson's ratio and strain have no units — they never change.
Consistent unit systems
Rule: choose length, mass and time. Everything else follows — force = mass × length ÷ time², stress = force ÷ length².
What to type in your solver
Highlighted column = the system ANSYS Workbench users usually pick for structural work (mm, t, s → N, MPa).
Unit mistake detector PRO
Type the E and density exactly as you entered them in the solver. We'll tell you if they don't make sense together.
The five unit mistakes we see most
| Mistake | What happens | Fix |
|---|---|---|
| Density 7850 in an mm model | Mass 10¹² × too high — natural frequencies far too low, gravity loads huge | Use 7.85e-9 t/mm³ in mm-t-s |
| E in GPa with geometry in mm | Stiffness 1000 × too low — deflections 1000 × too high | Use MPa (200 000) in mm-t-s |
| Gravity 9.81 with mm | Gravity 1000 × too small | Use 9810 mm/s² |
| Imported CAD in metres, loads in mm system | Part is 1000 × too small | Check model size after import; set units before import |
| Mixing kN and N | Stresses off by 1000 | Convert all loads before entering |
Sanity check: the wave speed √(E/ρ) is about 5 000 m/s for steel and aluminium. If your values give something wildly different, a unit is wrong.