Fatigue life estimation in a beam subject to random loads using probabilistic methods in the frequency domain

Resumo

Mechanical structures subjected to alternating cyclic loads are subject to failure due to fatigue, a result-
ing from the accumulation of damage caused by alternating cycles. The aim of this work is the use of theoretical

random excitations of the stationary and Gaussian type in the computational study of probabilistic criteria in the
frequency domain for fatigue analysis in beams. Using the Finite Element Method to perform a dynamic analysis
of the system, a theoretical random load is applied to the structure and the Frequency Response Function, PSD
(Power Spectrum Density) and spectral parameters are calculated. With these structural characteristics, the fatigue
life of the requested structure is estimated using several probabilistic criteria, comparing the values obtained and
analyzing the difference of each methodology. From these results, it is possible to verify the importance of fatigue
life calculation of dynamic systems, the efficiency of modeling procedures as a tool for fatigue analysis of random
dynamic systems and also the influence of the variation of the results obtained in this type of structure.