Calculation of Random Vibration Fatigue Life from Finite Element Model Calculations

Exposure to random vibration excitation is a test criteria used to screen, compare, and validate components for automotive and aerospace applications. Finite element analysis is sometimes employed to help understand or correct random vibration induced failures. A logical and consistent method for calculating relative fatigue life due to random vibration is needed.

The method presented uses the calculated natural frequencies, normalized mode stresses, modal participation factors, and modal damping ratios to synthesize a representative time history which can then be processed through existing damage calculation algorithms such as rainflow counting.