Estimate fatigue margins for repeated loading and maintenance planning. Compare Goodman and Soderberg checks easily. Make informed workload decisions with clear stress safety outputs.
| Case | Alternating Stress | Mean Stress | Endurance Limit | Yield Strength | Ultimate Strength | Target Factor |
|---|---|---|---|---|---|---|
| Drive shaft | 120 | 80 | 240 | 360 | 480 | 1.5 |
| Bracket arm | 95 | 60 | 210 | 330 | 450 | 1.4 |
| Rotating pin | 150 | 90 | 260 | 390 | 520 | 1.8 |
The calculator uses classic fatigue design relations for repeated loading.
Maximum Stress: σmax = σm + σa
Minimum Stress: σmin = σm − σa
Stress Ratio: R = σmin / σmax
Goodman Safety Factor: n = 1 / [(σa / Se) + (σm / Sut)]
Soderberg Safety Factor: n = 1 / [(σa / Se) + (σm / Sy)]
Gerber Safety Factor: n = 1 / [(σa / Se) + (σm / Sut)²]
Here, σa is alternating stress, σm is mean stress, Se is endurance limit, Sy is yield strength, and Sut is ultimate tensile strength.
A fatigue safety factor calculator helps estimate how safely a part handles repeated stress. Repeated loading can cause failure even when stress stays below static strength limits. This makes fatigue review important for reliability planning, inspection timing, and maintenance control.
This tool fits time management work because fatigue analysis affects maintenance timing. Engineers and planners often decide when equipment should be inspected, repaired, or replaced. A higher safety factor may support longer service intervals. A lower result may require faster review and closer monitoring.
The calculator uses alternating stress, mean stress, endurance limit, yield strength, and ultimate strength. It then estimates fatigue safety factors with Goodman, Soderberg, and Gerber methods. These methods help compare conservative and less conservative design perspectives during repeated service conditions.
The maximum and minimum stress values describe the loading range. The stress ratio adds more context for cyclic behavior. Goodman results are common for practical design checks. Soderberg is stricter because it uses yield strength. Gerber can be helpful when a smoother parabolic model is preferred.
You can use the output for maintenance planning, downtime review, and asset scheduling. The export options also support reporting workflows. Teams can save results as CSV for spreadsheets or PDF for quick records. This makes documentation easier during audits, inspections, and recurring project reviews.
This calculator supports early analysis. It does not replace full material testing or detailed design verification. Always confirm assumptions, loading history, surface finish, and correction factors before final decisions. Good fatigue planning improves reliability, protects timelines, and reduces costly unexpected stoppages.
A fatigue safety factor shows how much margin a part has under repeated loading. Higher values generally indicate better protection against fatigue failure during cyclic service.
They provide different design views. Goodman is widely used in practice. Soderberg is more conservative because it compares mean stress with yield strength.
Alternating stress is half the total stress range in a repeating load cycle. It represents the fluctuating part that drives fatigue damage.
Mean stress is the average stress during one full load cycle. It shifts the load level upward or downward and changes fatigue performance.
The endurance limit estimates the stress level a material may survive for many cycles. It is a core input for fatigue safety calculations.
Yes. Lower safety factors can signal shorter review intervals. Teams often use fatigue margins to plan inspections, replacements, and downtime windows.
Use one consistent stress unit for every input. MPa or psi both work, but all entered strength and stress values must match.
No. It is useful for screening and planning. Final approval should also consider real loading history, notch effects, material data, and testing.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.