What Is Finite Element Analysis?
The Finite Element Analysis (FEA) is a computer method that helps engineers predict how a real part or structure behaves under different conditions.
- The FEA divides a complex object into many small, simple parts called elements. These elements are connected together at nodes.
- The creation of the discrete elements is called discretisation, and the collection of nodes and elements is called a mesh.
- Each element has respective equations that describe how the element reacts to forces, pressure, heat, or other effects.
- The computer links all the equations of the elements together, and solves them as one large system of equations.
- The solution (of the system of equations) shows what happens to the whole object.
To learn more deeply about Finite Element Analysis, check out this guide:
Finite Element Analysis Explained: Design Optimization Made Simple.
Why Is Troubleshooting Necessary For Finite Element Analysis?
Troubleshooting is necessary in finite element analysis because FEA results are only as good as the assumptions and inputs used to build the model!
Small mistakes in geometry, boundary conditions, loads, materials, or mesh can lead to results that look precise but are physically wrong. Without troubleshooting, these errors can go unnoticed and lead to incorrect design decisions.
Troubleshooting helps us make sure that the model represents real behavior, that the physics make sense, and that the results can be trusted before they are used for engineering or business decisions.
Step-by-step Troubleshooting
For Finite Element Analysis:
Troubleshooting in Finite Element Analysis (FEA) is a disciplined, step-by-step process.
The trouble in the analysis can result from:
- Modeling errors
- Numerical issues
- Physical misrepresentation
Most problems come from modeling errors, not from the software solver itself. The goal is to check the physics step by step and remove sources of error.
1. Start With Basic Reality Checks
Before you change any solver settings, ask simple questions:
- Do the results look reasonable in size?
- Are stresses close to what hand calculations predict?
- For linear models, do displacements increase proportionally with load?
- Do reaction forces balance the applied loads?
If something looks wrong here, the issue is almost always model setup, not numerical accuracy.
2. Review Geometry and Model Scope
Overly complex geometry is a common problem!
Common problems:
- Too much CAD detail.
- Gaps or overlapping faces.
- Features that do not affect structural behavior.
What to do:
- Simplify the geometry.
- Remove fillets, threads, logos, and very small features.
- Keep only geometry that affects stiffness or load transfer.
Tip!
If a feature does not influence the load path, remove it.
3. Check Boundary Conditions and Constraints
This is the most frequent source of FEA errors.
Common problems:
- Too many constraints, making the model unrealistically stiff
(not enough stiffness). - Too few constraints, causing rigid body motion
(too much stiffness). - Fixed supports that do not represent real conditions.
What to do:
- Visually inspect all constraints.
- Confirm each constraint has a physical meaning.
- Compare reaction forces to expected values.
Tip!
If there is perfect symmetry in results, when the problem is not symmetric, there is a problem.
4. Verify Loads and Load Paths
Incorrect load application leads to misleading results.
Common problems:
- Applying loads to single nodes.
- Wrong load direction or magnitude.
- Missing or unrealistic load transfer.
(meaning that the way the load moves through the model does not match how the load moves through the real structure).
What to do:
- Apply loads as pressures or distributed forces.
- Trace how the load moves from application point to supports.
- Make sure that load cases match real operating conditions.
5. Check Mesh Quality and Convergence
Mesh quality directly affects accuracy.
Common problems:
- Distorted or stretched elements.
- Large changes in element size.
- Coarse mesh in high-stress areas.
What to do:
- Check element quality metrics.
- Refine the mesh only where needed.
- Perform a mesh convergence study.
Tip!
If results change significantly when the mesh is refined, they are not yet reliable.
If results change with mesh refinement, the solution hasn’t converged.
6. Confirm Material Models and Properties
Material definitions are a frequent source of error.
Common problems:
- Incorrect units (super common!).
- Unrealistic stiffness values.
- Using linear materials for nonlinear behavior.
What to do:
- Check unit consistency.
- Verify material data sources.
- Use nonlinear material models when plastic deformation or large strains are expected.
7. Review Contacts and Interfaces
Contact definitions often cause instability.
Common problems:
- Contacts that are too stiff.
- Poor contact detection.
- Incorrect friction values.
What to do:
- Start with simple contact definitions.
- Add friction only if required.
- Monitor contact status and penetration.
Tip!
Many convergence problems originate from contact settings.
8. Adjust Solver Settings
Solver settings should be adjusted only after fixing the model.
When necessary:
- Reduce load step size:
Instead of applying the full load at once, the solver applies it gradually in smaller increments. This helps nonlinear problems converge more reliably. - Use incremental loading:
Similar to reducing load steps, this breaks the total load or displacement into multiple steps to stabilize the calculation. - Enable numerical stabilization carefully:
Some solvers allow small artificial damping or stabilization to help the system converge, especially in unstable or highly nonlinear cases. Use it sparingly, as excessive stabilization can mask real physics. - Change solver type if appropriate:
Solvers can be implicit or explicit. Implicit solvers are usually more stable for static problems, while explicit solvers are better for highly nonlinear or dynamic problems. A change of the solver type can help, when convergence is difficult.
Tip!
Solver tuning does not fix incorrect modeling assumptions.
9. Interpret Results Carefully
Not every result is physically meaningful!
Common problems:
- Stress spikes at sharp corners:
Sharp corners can produce extremely high stress values that do not exist in the real structure. - Over-reliance on peak von Mises stress:
Peak von Mises stress may exaggerate local effects and mislead decisions. - Ignoring averaging settings:
Software often calculates element-level stresses, so you must check averaged or section stresses to get realistic results.
What to do:
- Always focus on trends and patterns, not single extreme value or isolated peaks.
- Use section cuts and stress paths, to check averaged or section stresses, and to get realistic results.
- Compare results to material limits and design criteria.
Tip!
Infinite stress at a sharp corner is a mathematical artifact, not a real failure.
10. Verify and Validate the Model
Final confidence comes from comparison.
Good practices:
- Compare results with hand calculations.
- Perform sensitivity checks:
To do a sensitivity check is to test one input at a time and observe how results such as stress or displacement respond. Large changes indicate a sensitive or unreliable model. - Correlate with test data when available:
To correlate with test data is to compare FEA results with experimental measurements when available. This process identifies discrepancies, confirms model accuracy, and ensures that the simulation reflects real-world behavior.
Tip!
Change only one parameter at a time to understand cause and effect.
Troubleshooting Table
With Practical Solutions To Each FEA Problem
You can use this toubleshooting table for Finite Element Analysis, when necessary:
| Problem | Possible Cause | Solution |
| Solver does not converge | Under-constrained model (rigid body motion) | Add minimal physical constraints; Check that all degrees of freedom are restrained |
| Solver does not converge | Over-constrained model (artificial stiffness) | Remove redundant or conflicting constraints; Make sure that supports reflect real conditions |
| Solver diverges | Incorrect contact definition or friction | Start with bonded or frictionless contact; refine mesh near contact; Monitor penetration |
| Non-convergence in nonlinear analysis | Load applied too quickly or too large | Apply loads incrementally; Reduce load step size |
| Unrealistic displacements | Loads applied incorrectly or units mismatch | Verify load magnitude, direction, and unit consistency |
| Reaction forces do not match applied loads | Incorrect constraints or missing load paths | Check constraints and load application points; Make sure that load transfer is correct |
| Stress spikes at sharp corners | Geometric singularities | Add fillets or focus on average stress away from singularities |
| Highly asymmetric results in a symmetric model | Inconsistent boundary conditions | Verify symmetry of constraints and load application |
| Results vary significantly with mesh refinement | Mesh too coarse or poorly shaped | Refine mesh in critical areas; Do a mesh convergence study |
| Unrealistic stiffness | Incorrect material properties | Verify modulus, Poisson’s ratio, and units; Use correct material model |
| Excessive solver time | Overly fine mesh throughout the model | Use local refinement only in critical regions |
| No deformation under load | Load applied to constrained nodes | Reapply loads to free nodes or surfaces; Check direction |
| Oscillating or unstable solution | Numerical instability | Enable stabilization, reduce load steps, or switch solver type |
| Unrealistic plastic deformation | Linear material model used for nonlinear behavior | Switch to appropriate nonlinear or elastoplastic material model |
| Contact forces unrealistic | Wrong friction coefficient or contact definition | Verify friction data and re-check contact definitions |
| Thermal stresses unexpected | Incorrect thermal loads or constraints | Check temperature loads, constraints, and thermal expansion coefficients |
| Modal frequencies incorrect | Wrong mass properties or boundary conditions | Verify density, added masses, and supports |
Conclusion
- Most FEA problems are caused by how the model is built, not by the solver itself.
- Effective troubleshooting means systematically checking the physics, boundary conditions, loads, geometry, mesh, material definitions, and contacts before adjusting solver settings.
- When you follow a structured, step-by-step approach, you can quickly identify and fix errors, make sure that results are physically meaningful, and build confidence in your simulations.
