EngineeringToolkit

Fatigue Life (S-N) Formula

Relates stress amplitude to number of cycles to failure.

Formula

S = aN^b

Discipline: Materials Engineering. Result unit: Pa.

Variables and units

  • S — Stress Amplitude (Pa): Stress amplitude
  • a — Coefficient (Pa): Material constant
  • N — Cycles to Failure: Number of cycles to failure
  • b — Exponent: Material exponent