How to Do Fatigue Analysis in SOLIDWORKS

Fatigue analysis estimates whether a part may fail under repeated loading. In SOLIDWORKS Simulation, fatigue studies use stress results from static studies along with loading cycles, material data, and fatigue curves. The goal is to understand life, damage, and safety under cyclic loading.

Start with a valid static study

A fatigue study depends on stress results from one or more static studies. Create the static study first, apply realistic fixtures and loads, mesh the model, and solve it. If the static study is not meaningful, the fatigue result will not be meaningful either.

Pay special attention to constraints. Overly rigid fixtures can create artificial stress concentrations, while unrealistic loads can make the fatigue result look safer or worse than the real part.

Check material fatigue data

Fatigue analysis needs material fatigue information such as an S-N curve. Confirm that the assigned material has appropriate fatigue data or add reliable data from a trusted engineering source. Do not assume a material is ready for fatigue analysis just because it has density or yield strength.

If the material data is approximate, state that clearly in the study notes. Fatigue life can change significantly when the material curve, surface finish, or manufacturing process changes.

Also confirm that the part uses the same material condition that the fatigue data represents. Heat treatment, welding, machining marks, and surface finish can all affect fatigue behavior, especially near shoulders, holes, grooves, and other stress raisers.

Create the fatigue study

1. Create and solve the required static study.
2. Create a new fatigue study.
3. Select the static study events or loading cases.
4. Define cycles, loading type, and fatigue settings.
5. Run the fatigue study.
6. Review life, damage, and factor of safety plots.

Define loading cycles

Repeated loading is the core of fatigue analysis. Define the number of cycles and loading pattern carefully. A fully reversed load, zero-based load, and fluctuating load can produce different fatigue results even when peak stress looks similar.

Use a load case that matches how the part is actually used. If the part sees several load levels, consider whether multiple events are needed instead of one simplified cycle.

When the real loading is uncertain, run a few reasonable scenarios instead of relying on one optimistic case. Comparing a light-duty case, expected case, and severe case can show whether the design is sensitive to cycle count or load magnitude.

Review the results carefully

Fatigue plots can show life, damage, and safety factor. Look for high-damage regions, sharp stress concentrations, poor mesh quality, and unrealistic fixture effects. Fatigue results should be interpreted with engineering judgment, not treated as a simple pass or fail graphic.

Zoom in on critical locations and compare them to the static stress plot. If the highest fatigue damage is caused by a mesh artifact or unrealistic constraint, refine the setup before making design decisions.

Troubleshooting

If the fatigue study will not solve, check that the referenced static study is solved and that the material has fatigue data. If results look unrealistic, refine the mesh near stress concentrations, review fixtures, and confirm the load cycle definition.

Fatigue analysis is only as reliable as the assumptions behind it. Document the loads, cycles, material data, and boundary conditions before using results for design decisions.

For high-risk parts, use fatigue analysis as one input, not the only proof. Testing, standards, and experienced engineering review may still be required.

Keep the study file, assumptions, and result plots together with the design revision. That record is useful if the part is changed later or if another engineer needs to understand why a design decision was made.