Fatigue Life Estimation of Notched Components using Frequency Domain Approach

Abstract

Engineering structures are constructed to withstand a variety of in-service loading specific to their application. Random vibration excitation is observed in most structural components in the offshore, aerospace, and automotive industries. Likewise, fatigue life estimation for structural elements is fundamental for verifying the design and assurance of structural integrity throughout service. The linear cumulative Palmgren-Miner's damage rule is widely used for damage assessment, despite its well-known limitations. The scatter of fatigue testing data suggests that a probabilistic characterization of the material behavior should be considered during fatigue life predictions. In this work, the inherent uncertainties of the fatigue phenomenon and the influence of a geometrical discontinuity are explored in the fatigue life estimation of a structural component subjected to random vibration profiles. The fatigue life estimated using the methodology proposed in this work presented a good agreement with testing results using Dirlik frequency domain counting methods.