Convergence Errors
Why the nonlinear solver fails to converge and how to fix it.
If you only have 2 minutes
Convergence failures in nonlinear analyses are almost always caused by missing boundary conditions, contact problems, load steps that are too large, or poor mesh quality.
Symptoms
- Error code E1002
- Solver aborts after reaching the maximum number of iterations
- Residual forces don't drop below the convergence tolerance
Root causes
| Cause | Fix | | --- | --- | | Missing boundary condition (rigid body movement) | Add the missing support | | Contact surfaces initially penetrating | Correct geometry so parts don't overlap at start | | Load steps too large (nonlinear) | Increase number of load steps | | Distorted mesh elements | Re-mesh with better quality settings |
Diagnostic approach
- Run a linear static solver first — if that also fails, the problem is a missing boundary condition (rigid body movement), not a nonlinearity issue
- Verify boundary conditions visually in the 3D viewer
- For nonlinear: reduce load step size
- Refine the mesh in problem areas
- Check contact definitions for initial penetrations
Always start with the linear static solver. It's faster and diagnoses setup errors more clearly than the nonlinear solver, which can obscure the root cause behind convergence failure messages.