Combined effects of interference fit size and installation speed on fatigue property of CFRP/Ti double-lap joint with interference bushing

The application of interference bushings in Carbon Fiber Reinforced Polymer (CFRP) joints has demonstrated significant potential in enhancing fatigue life performance. However, the lack of in-depth research on key installation process parameters—particularly interference fit size and installation speed—has limited broader application of this technique. To fill in this gap, this study designed a series of experiments to investigate the effects of these two parameters on the fatigue performance of CFRP/Ti double-lap joints. This study utilized stress wave separation technology to accurately measure the installation displacement, speed, and resistance under varying installation speeds. Real-time structural damage monitoring was conducted through circumferential strain measurements and acoustic emission analysis. By establishing a correlation among installation parameters, damage characteristics, and fatigue life outcomes, the study reveals that a smaller interference fit size combined with a higher installation speed can effectively reduce installation-induced damage and significantly enhance joint fatigue performance.