Goodman Diagram Checker
Mean-stress fatigue check: is your (σm, σa) point inside the Goodman line?
Tensile mean stress eats fatigue life; compressive mean (shot peening's gift) extends it. Goodman is the conservative classic — Gerber's parabola gives ~15% more credit.
Formula
Goodman Diagram Checker is a free goodman diagram for design engineers, metallurgists and QA inspectors — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Goodman Diagram Checker
Mean-stress fatigue check: is your (σm, σa) point inside the Goodman line? The calculation implements σ_a/S_e + σ_m/S_u = 1/n (Goodman (1899); Shigley ch. 6). Tensile mean stress eats fatigue life; compressive mean (shot peening's gift) extends it. Goodman is the conservative classic — Gerber's parabola gives ~15% more credit.
How to use Goodman Diagram Checker
- 1Enter Stress amplitude σ_a in MPa.
- 2Enter Mean stress σ_m in MPa.
- 3Enter Endurance limit S_e in MPa.
- 4Enter Ultimate strength S_u in MPa.
- 5Read Goodman safety factor instantly — no submit button needed.
- 6Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Goodman Diagram Checker?
- ✓Implements the standard formula — σ_a/S_e + σ_m/S_u = 1/n
- ✓Reference cited on-page: Goodman (1899); Shigley ch. 6
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Built-in engineering verdict flags out-of-range results instantly
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Goodman Diagram Checker use?+
It computes σ_a/S_e + σ_m/S_u = 1/n, per Goodman (1899); Shigley ch. 6. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
Tensile mean stress eats fatigue life; compressive mean (shot peening's gift) extends it. Goodman is the conservative classic — Gerber's parabola gives ~15% more credit.
Where do the material property defaults come from?+
Defaults are standard handbook values (ASM, manufacturer datasheets, the cited standard). Always substitute certified values from your material's test certificate for critical work.
Is the Goodman Diagram Checker free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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