Goodman Fatigue Diagram Calculator

Evaluate fatigue life using the Modified Goodman criterion: σ_a/σ_e + σ_m/σ_u = 1. Compare with Soderberg (uses yield) and Gerber (parabolic) criteria for safety factor calculation.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)
σy — Normal Stress Y (MPa)
τxy — Shear Stress (MPa)
⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.
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How It Works

Evaluate fatigue life using the Modified Goodman criterion: σ_a/σ_e + σ_m/σ_u = 1. Compare with Soderberg (uses yield) and Gerber (parabolic) criteria for safety factor calculation

Each component has a specific meaning:

  • Modified Goodman criterion: σ_a/σ_e + σ_m/σ_u = 1 — The modified goodman criterion: σ_a/σ_e + σ_m/σ_u = 1 recorded for the patient or scenario being assessed.

Note: Interpret the goodman fatigue result against the clinical thresholds and context described above.

How to Use

Enter the Modified Goodman criterion: σ_a/σ_e + σ_m/σ_u = 1 for the patient or scenario you are assessing. Evaluate fatigue life using the Modified Goodman criterion: σ_a/σ_e + σ_m/σ_u = 1. Compare with Soderberg (uses yield) and Gerber (parabolic) criteria for safety factor calculation. Use the goodman fatigue result to inform your clinical assessment.

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Frequently Asked Questions