Fatigue Life Prediction of Electronic Components Using Random Response Analysis and Dirlik Method

Abstract

Print circuit board (PCB) mounted on transportation equipment receive various random loads from the outside as vibrations during running. We sometimes experience that fatigue failure of electrical component leads under random loading and so it is very important to evaluate the fatigue life in the design of PCB. In general, we calculate the response power spectrum density (PSD) for random loads with FEM, and fatigue life is predicted in the frequency domain. However, fatigue fracture occurs in localized stress areas due to shape change, so handling of localized stress is an issue for improving the accuracy of predicting fatigue life. In this paper, we research the predicted life using Dirlik’s method with Hot Spot stress and the S-N curve considering the stress concentration factor. And we compare the predicted life with the rupture life obtained from random vibration tests on the PCB. As a result, we can confirmed that these predicted lives are close to the experimental results, and the life estimation considering the stress concentration is effective for the fatigue life evaluation of the bent portion of the terminal of electronic parts.