EngiRef / Materials Engineering Formula
Goodman Diagram (Fatigue)
Goodman Diagram (Fatigue): Modified Goodman line for fatigue design. A Fatigue formula in materials engineering. Variables σₐ, σₘ, Sₑ and Sᵤₜ, each with SI and…
Fatigue
Specification
- Name
- Goodman Diagram (Fatigue)
- Discipline
- materials
- Category
- Fatigue
- LaTeX
- \frac{\sigma_a}{S_e} + \frac{\sigma_m}{S_{ut}} = 1
- Description
- Modified Goodman line for fatigue design
- Conditions
- Conservative for most ductile metals
- Can solve for
- σₐ, σₘ
- Tags
- goodman, fatigue, mean, stress, endurance
Variables
| Symbol | Name | Unit | Si Unit | Imperial Unit |
|---|---|---|---|---|
| σₐ | Stress Amplitude | Pa | Pa | psi |
| σₘ | Mean Stress | Pa | Pa | psi |
| Sₑ | Endurance Limit | Pa | Pa | psi |
| Sᵤₜ | Ultimate Tensile Strength | Pa | Pa | psi |
Common questions
- What is the Goodman Diagram (Fatigue) formula?
- Modified Goodman line for fatigue design. It sits under Fatigue, Materials engineering in the EngiRef reference.
- What do the symbols in the Goodman Diagram (Fatigue) formula mean?
- In Goodman Diagram (Fatigue), σₐ is stress amplitude in Pa; σₘ is mean stress in Pa; Sₑ is endurance limit in Pa; Sᵤₜ is ultimate tensile strength in Pa.
- When does the Goodman Diagram (Fatigue) formula apply?
- Goodman Diagram (Fatigue) holds under this condition: Conservative for most ductile metals.