Fatigue Life Calculator (S-N Curve)
Estimate fatigue life from stress amplitude and cycles using an S-N curve model.
Calculator
Results
Estimated Fatigue Life
0 cycles
Data Source and Methodology
All calculations are based on the S-N curve methodology as outlined in the Fatigue Design Handbook.
The Formula Explained
S-N Curve: \( N = \left( \frac{\sigma_a}{\sigma_e} \right)^b \)
Glossary of Terms
- Stress Amplitude (\(\sigma_a\)): The stress level at each cycle.
- Cycles to Failure (N): Number of cycles material can withstand before failure.
How It Works: A Step-by-Step Example
For a stress amplitude of 150 MPa, the estimated fatigue life is 10,000 cycles using the S-N curve method.
Frequently Asked Questions (FAQ)
What is fatigue life?
Fatigue life is the number of cycles a material can endure before failure.
How is the S-N curve used?
The S-N curve is used to predict the number of cycles to failure for a given stress level.
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
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Formula (extracted text)
S-N Curve: \( N = \left( \frac{\sigma_a}{\sigma_e} \right)^b \)
Variables and units
- No variables provided in audit spec.
Sources (authoritative):
- Fatigue Design Handbook — efatigue.com · Accessed 2026-01-19
https://www.efatigue.com/fatiguecalc.html
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.