Langford Analytic · Knowledge Base

Random Vibration Fatigue Best Practices

Best practices for vibration fatigue assessment — method selection, S-N data, damping sensitivity and validation against time-domain.

Random Vibration6 min read
best practicesfatiguerandom vibrationDirliknarrow-banddamping sensitivity

Best practices

  • Check irregularity factor — narrow-band (α≈1) vs broad-band (α<0.8)
  • Use narrow-band for single-mode response; Dirlik for broadband
  • Use material-specific S-N data — do not use generic values for final assessment
  • Run damping sensitivity for fatigue LIFE (not just RMS) — life is extremely sensitive
  • Validate frequency-domain results against time-domain rainflow for critical components
  • Assess multiple critical locations — highest RMS ≠ shortest life
  • Include mean stress and stress concentration where relevant