Study On Anti-loosening Performance Of Wedge-shaped Gasket And Toothed Double Nuts

Threaded connection structures are widely used in the aerospace,petrochemical,mechanical engineering,and other fields due to their advantages of high safety,easy disassembly,and reliable performance.During the long-term service of threaded connection structures,they will inevitably be subjected to external loads such as impact loads,resulting in a decrease in bolt preload.Maintaining a stable preload of the bolts is the key to ensuring high reliability of the connection structure,The loss of preload poses a serious safety hazard to the stable operation of the overall structure.Therefore,this article systematically conducted research on the anti-loosening performance of wedge-shaped gasket anti-loosening structure,and proposed a new type of toothed double nut structure.At the same time,detailed research and analysis were conducted on it,which has certain significance for optimizing bolt anti loosening design and maintaining the stable operation of the overall structure.The main research content of the thesis is as follows:(1)Through the finite element analysis of the wedge-shaped gasket using the display solution method,it was found that under lateral transient impact load,the initial preload,load amplitude,and load waveform all have a certain impact on the anti-loosening performance of the wedge-shaped gasket;Under lateral periodic vibration loads,from the perspective of the structure,both the wedge angle and tooth surface angle had an impact on the anti-loosening performance of the wedge gasket,and the position of the gasket was also one of the factors affecting its anti-loosening performance.The results show that the larger the initial preload,the smaller the amplitude of the impact load,and the better the anti-loosening performance of the wedge-shaped gasket.The sine wave load has a more significant impact on bolt loosening;The larger the wedge angle and tooth surface angle,the better the anti-loosening performance of the wedge gasket.The wedge gasket is placed at the top of the nut as the most suitable position.(2)Through implicit solution method,finite element analysis was conducted on the tooth shaped double nut to determine the relationship between the anti-loosening performance of the tooth shaped double nut and the pre tightening force and micro slip angle.Based on the pre tightening force,the influence of load amplitude,wedge angle,and tooth number on the anti-loosening performance under lateral impact load was studied.The anti-loosening effect of the tooth shaped double nut over a long period of time was studied using periodic vibration load.The results show that the larger the amplitude of the impact load,the faster the decrease in preload,and the more obvious the loosening phenomenon;When the wedge angle and thread rise angle are the same,the anti-loosening performance of the toothed double nut is poor;The more the number of teeth,the better the anti-loosening performance;When the vibration time is long,the toothed double nut still has a certain anti-loosening effect.(3)Through drop impact tests,the anti-loosening conditions of different devices were compared,and the influence of impact load amplitude on the wedge-shaped gasket and toothed double nut was studied.The results show that the wedge-shaped gasket and toothed double nut have good anti-loosening performance,with the same pattern.The larger the load amplitude,the easier it is for loosening to occur.The experimental results are basically consistent with the simulation results.