You can have a beautiful mesh, a powerful computer and a detailed material model—and still get a meaningless FEA result.
One of the most common reasons is unrealistic boundary conditions.
## Why constraints matter
A simulation needs to know how the component is supported and loaded.
If you completely fix a large surface that is actually mounted through flexible bolts, the model may become much stiffer than the real component.
The resulting stress and deformation can be misleading.
## Reproduce the real load path
Instead of asking:
“Where can I fix this model?”
Ask:
“How is this part actually supported?”
Is it bolted?
Pinned?
Welded?
Clamped?
Supported through a bearing?
The answer should guide the boundary condition.
## Avoid over-constraining
Too many fixed degrees of freedom can artificially increase stiffness and create unrealistic stress concentrations.
This is especially easy to do when modelling a complicated assembly.
## Apply loads where they enter reality
A point force may be convenient, but the real load could be distributed across a bearing, bolt group or contact surface.
Whenever the load path matters, represent it appropriately.
## Use reaction forces as a sanity check
After solving, look at reactions.
Do they make physical sense?
If the total reaction does not balance the applied loading, something needs investigation.
## Compare simulation with engineering intuition
FEA should support engineering judgement, not replace it.
If a thin plate carrying a modest load suddenly shows an absurd deformation or stress value, do not immediately conclude the material is failing.
Check:
– Constraints – Loads – Contacts – Mesh – Units – Geometry – Material properties
Simulation is powerful when the model represents the real world.