Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 03, 2023 - September 06, 2023
The connection of bolts and nuts is an important mechanical component. In the case of a single nut, there is a high likelihood of the nut becoming loose, which will lead to a serious accident. In the case of double nuts, the nuts are less likely to loosen, but their removal becomes more difficult. To solve these problems, a new bolt called PLB has been developed. In this study, Junker vibration tests in which bolted fasteners are subjected to vibration and numerical analysis modeling the experiments will be conducted to investigate the phenomena that cause loosening. The experiment was performed 3 times and the result was calculated as the average value. The bolt was vibrated 2000 times by moving the vibration plate up and down with an axial force of 20kN and a vibration frequency of 12.5Hz. After that, this experiment was modeled by computer and numerical analysis was performed. Marc/Mentat2018, a general-purpose finite element code, was used for numerical analysis. Regarding the single nut, the reason for the loss of residual axial force is thought to be that the directions of the tangential force acting on the nut were scattered when vibration was applied. The high locking performance of the double nut is because the two nuts pull the bolt in opposite directions. Regarding PLB, it was found that high locking performance was obtained because the contact state between the bolt and nut resembled a double nut.
