An Evaluation of NDT for Self-pierce Riveting

An evaluation of Non-Destructive-Testing (NDT) technique based on ultrasonic inspection for self-piercing riveted (SPR) joints was conducted. A riveted joint is inspected by an ultrasonic continuous wave through a differential piezoelectric transducer operated at a predetermined frequency. The joint quality is evaluated by monitoring variations in the electrical impedance of the transducer represented by both the phase and the amplitude displayed in the complex impedance plane. A range of SPR joints were tested using the NDT technique and the NDT results were compared with laboratory sectioning of samples. It was observed that for some of the aluminium joints with two or three layers, the NDT technique could arguably detect sound and bad joints. The work has also shown that for joints involving very thin aluminium sheets and steel panels, the sensitivity of the technique needs to be improved.