A Study on Self-loosening of 3D Printed Bolted Joints

초록

A bolt joint is a simple element that combines mechanical components. Self-loosening of bolted joints occurs due to the vibrations caused by motors and engines, resulting in the breakage of machines, deterioration of performance, and potentially serious safety problems. Recently, developments in 3D printing technologies have enabled the fabrication of detailed components. These technologies can be used for producing fasteners using 3D printed bolts. Many researchers have proposed a theoretical model for self-loosening of the steel bolt, and experimental studies on the self-loosening phenomenon have been advanced. However, studies on the self-loosening of 3D printed bolts have not been conducted. Therefore, it aims to confirm the self-loosening phenomenon and the safety of 3D printed bolts through experiments and finite element simulation. Furthermore, the self-loosening phenomena in the cases of transverse vibration of standard M12 steel bolts and bolts made using 3D printers are compared. A lateral vibration test system using a motor is constructed and self-loosening of the bolt is evaluated by observing the axial force according to the vibration cycle by using a strain gauge. This study confirms the self-loosening of 3D printed bolts and steel bolts by changing the preload and amplitude. In addition, the experimental results are verified through finite element simulation. Experimental results show that the 3D printed bolt has more loss of clamping force than a steel bolt. Through this study, it is expected that 3D printed bolts will be used more frequently in situations where specially shaped bolts are needed.