Quantitative Identification and Prediction of 5182 Aluminum Alloy Clinched Joint Fatigue Life

Clinching has emerged as a key research area in lightweight automotive design. A single-lap clinched joint of 5182 aluminum alloy was selected as the subject of this study. A dynamic response test platform was developed to conduct fatigue–dynamic response tests on clinched joints. The rate of change in the natural frequency characterizes the stages of fatigue failure, and a life cycle prediction model for clinched joints was established. The results indicate significant changes in the 14th-order natural frequency under high and medium loads, whereas the ninth-order frequency changes significantly at low loads. The crack propagation rate was the highest at the medium load level, and the natural frequency change remained stable for the first 66% of its lifespan, with significant changes following crack initiation. The proposed prediction model quantitatively identifies the real-time service state of a clinched joint and predicts its fatigue life.