The Analysis of Loosening of Bolt Connection Due to Structural Vibration Through Changes in Dynamic Characteristics

Bolted joints are generally used to connect two or more mechanical structures due their ease of assembly and disassembly for maintenance. However, the problem vibration is one main challenges when tightness bolted insufficient, causing failures such as looseness resulting in disconnection. Looseness most common cause dynamically loaded joint structure failure. This study tested a simple bolt observe indication after it was vibrated using shaker single-frequency excitation. A freely fixed beam consisting beams connected by subjected varying tightening torques. Then response measurement carried out recording FRF graph obtained from loosening torque effects. Modal parameters personal frequency damping ratio were collected through experimental modal analysis (EMA). It found that structure’s could change conditions lower indicated shifting natural frequency. In addition, characteristics also affected changes torque. Especially loose, becomes much higher than tightening.