Fatigue Life Estimation of Notched Beam Under Random Vibrations Using Strain Gauge Data

Fatigue life estimation under random vibrations is critical for ensuring the safety and durability of structural components in real-world operating environments. This work focuses on the fatigue life estimation of a notched beam subjected to random vibrations using strain gauge data in the frequency domain. The strain gauge data obtained experimentally may be used in conjunction with a structural model to perform response analysis. The stress response at the critical (notched) region of the beam is determined, and its corresponding stress PSD is evaluated. This PSD is then combined with the probability density function (PDF) of rainflow stress ranges to characterize the statistical distribution of stress amplitudes. Fatigue damage is computed using Miner’s rule, incorporating the S-N curve relationship for the material. This integrated approach enables fatigue life prediction under random vibration loading considering both the dynamic characteristics of the structure and the statistical nature of the stress response. The workflow emphasizes the advantage of frequency-domain methods in handling vibration-induced fatigue problems efficiently and reliably.