Competitive Failure of Bolt Loosening and Fatigue under Different Preloads

• 作者: Guangwu Yang Long Yang Jingsong Chen Shoune Xiao Shilin Jiang
• 来源期刊: 中国机械工程学报
• 年，卷（期）: 2021,（6）
• 所属期刊栏目: Advanced Transportation Equipment
• 页码范围: 417-427
• 页数: 11页
• 语种: 英文

摘要

Existing research on the competitive failure relationship,failure mechanism,and influencing factors of bolt loosening and fatigue under different preloads is insufficient.This study analyzes the competitive failure relationship between bolt loosening and fatigue under composite excitation through competitive failure tests of bolt loosening and fatigue under different preloads.The results indicated that the failure mode of the bolt is only related to the load ratio(R)and is unrelated to the initial preload and excitation amplitude,which only determine the failure life of the bolt.The small axial loads of composite excitation can restrain bolt failure,and the significant degree of this restraining effect is differ-ent for different preloads.Subsequently,a fracture analysis of the bolt was performed to verify the competitive failure relationship of the bolt from a microscopic perspective,and the competitive failure mechanism of the bolt was deter-mined.Based on the findings,we propose a calculation equation for the optimal preload of 8.8 grade high-strength bolts that can serve as a reference for engineering applications.