Study on fatigue life of gun latch based on orthogonal test method

Abstract

Aiming at the problem of fatigue damage of gun latch caused by long-term impact load, the fatigue life of gun latch was studied. Firstly, the finite element model of gun latch was established by using finite element method. Secondly, the static strength and fatigue life of the gun latch were calculated based on S-N curve and Miner’s linear damage accumulation theory. On this basis, the structural factors affecting the fatigue life of the bolt were analyzed, and four factors including the radial diameter of the latch, the axial bearing thickness of the latch, the spiral Angle of the latch support surface and the gun tail support surface, and the locking clearance between the bolt and the gun tail were set up, as well as three variation levels of each factor. Then, the fatigue life of nine groups of gun latches was simulated by orthogonal test method. In addition, the range analysis method was used to analyze the simulation results, and then the influence law and degree of each factor on the fatigue life of gun latch were obtained. Moreover, the optimal combination scheme of the structure parameters of the gun latch was determined by the comprehensive balance method, and then the finite element simulation was carried out to verify the structure of the gun latch. The results show that the maximum stress of the bolt decreases 21.5% and the maximum stress of the gun tail decreases 28.2%, and the maximum stress of the gun bolt is lower than the yield limit of the material. At the same time, the research also shows that the minimum fatigue life of the bolt increases greatly, the minimum fatigue life of the bolt body is 20.8 times of that before the test, and the minimum fatigue life of the gun tail is 102.1 times of that before the test. The results provide a reference for fatigue life analysis and structural design of gun latch.