Fatigue Fracture Mechanism and Life Prediction of TA1 Titanium Alloy Clinched Joints

Abstract

This study investigated the fatigue fracture mechanisms and life prediction of clinched joints made from titanium alloy TA1. The fatigue tests revealed that TA1 titanium alloy clinched joints exhibited failure characterized by fracture of the lower plate at three distinct fatigue load levels. Additionally, finite element analysis indicated that cold work hardening enhanced the fatigue performance of these joints. Observations of fracture surfaces using scanning electron microscopy identified the crack source and its propagation path, which correlated with the location of maximum principal stress from the finite element simulations. Fretting wear was also observed in this critical region. Furthermore, fatigue life predictions for TA1 titanium alloy clinched joints were made using Paris' law and the local strain approach. Both methods closely matched experimental results across different fatigue life intervals. Overall, the local strain approach exhibited superior predictive capability compared to Paris' law, taking into account various influencing factors.