Some factors affecting the loosening failure of bolted joints under vibration using finite element analysis

Abstract

Finite element analysis has been regarded as an effective research method for analyzing the loosening failure of bolted joints under vibration. However, there exist some factors, which influence the accuracy and reliability of loosening results, thus determining the explanations of the loosening mechanism. In this study, a 3D finite element model of a typical bolted joint was built to investigate the effects of several different factors on the loosening under transverse vibration loading. These influencing factors include preload generation, vibration parameter, and material model. Based on the simulation results, it was found that applying the method of pretension element to generate preload instead of the actual method of torque was reliable and efficient. For the vibration parameter, it showed that the decrease rate in preload was higher for a larger vibration amplitude. But once the bearing surface reached complete slip, the loosening rate would keep constant. This was because the thread surface at that time reached a sticking state. Vibration frequency was proved to have no effect on the loosening behavior. This result demonstrated that the quasi-static assumption for vibration frequency was reasonable. Additionally, it also indicated that plastic material models only affected the preload loss in the initial several vibration cycles and had no influence on the loosening rate of preload after several vibration cycles. Finally, experiments were conducted to confirm qualitatively the results obtained based on finite element analysis.

Loosening of Bolted Connections under Transverse Loading in Timber Structures

“…In order to accurately simulate the tightening state of the bolts during assembly, Gong [35] compared the four methods of loading the bolts' preloading force to obtain a conclusion that the preloading force unit can better consider the accuracy and cost of the calculation. The model was analyzed by ABAQUS software (www.3ds.com/products-services/simulia/products/abaqus), and the bolt preload force was applied by the bolt load application method.…”

“…It could be considered that in the low frequency region, the increase of load frequency had little effect on the change of preload force in the process of bolt loosening. In the finite element analysis of bolt loosening of steel connection structures, Gong [35] set the preload force to 10 KN and the load amplitude to 0.3 mm. After 50 loading cycles, the preload force decreased to about 9400 N, a decrease of about 6%, and when the loading cycle is 14 s, the decrease is about 2.5%.…”

A Review of Challenges and Opportunities Associated with Bolted Flange Connections in the Offshore Wind Industry

“…Self-loosening happens when this stored energy is released as the result of overcoming of above mentioned friction forces by any means. There are various theories and previous works on the reason for self-loosening of bolts through vibration, thermal cycles, and thermal shock [34][35][36][37][38][39][40][41][42][43]. Broadly speaking, the works agree that, unless an external load acts on the bolted joint, the frictional forces will remain intact.…”

Research on the Numerical Calculation Method for Antiloosening Performance of Screwed Joints under Complex Working Conditions

“…e limit value of the safety margin is determined by the user. Gong and Liu developed a three-dimensional finite element model to investigate the effects of the preload generation, vibration parameter, and material model on the loosening [7] and identified the critical transverse force for initiating loosening [8]. Zhao et al [9] proposed a simplified numerical model of bolt slipping for simulating SJs and better capturing the slipping phenomenon.…”