Computation Time
Why your simulation is slow and how to speed it up.
If you only have 2 minutes
Long computation times are almost always caused by a mesh that's finer than the problem requires. Coarsen the global mesh and use local refinement only where needed.
Common causes
| Cause | Fix | | --- | --- | | Mesh too fine globally | Increase global element size; use local refinement only at critical areas | | Nonlinear solver with too many load steps | Reduce number of steps; start with fewer and add only if needed | | Unnecessary model detail | Remove small features, fillets, holes that don't affect the result | | Contact with very high stiffness | Reduce contact stiffness slightly |
Mesh size and compute time
Element count scales with the cube of refinement. Halving the element size produces 8× more elements and roughly 8× longer solve time. Be deliberate about where you spend resolution.
Run a coarse mesh first to check the setup is correct. Only refine once you've confirmed the boundary conditions, loads, and material are right.
When to use symmetry
If your geometry and loading are symmetric, model only half (or a quarter) and apply a symmetry boundary condition. This reduces element count by 2× or 4×, with a proportional reduction in solve time.
Nonlinear analysis tips
- Use the minimum number of load steps that achieves convergence
- Start from a converged linear solution as the initial condition
- Avoid unnecessary nonlinear features (e.g. frictional contact) if bonded contact is physically adequate