Analysis Of The Elastic-plastic Characteristics Of The Bushing During The Extrusion Process Of A Mechanical System Under The Action Of Strong Force

Modern revolving automatic mechanical systems have the characteristics of high initial velocity,high shooting frequency,and high barrel pressure when launching projectiles.At the same time,accompanied by the violent combustion of the base powder,a large amount of hightemperature and high-pressure powder gas is released.It is the most severe ablation at the beginning of the gun barrel.A new type of automatic machine studied in this thesis has both a revolving bushing and a gun-barrel bushing.The rotating bushing is located at the begin-ning of the body-pipe,where the wear of the rifling is the most serious.Plastic deformation is the focus of this analysis.The main research contents of this article are as follows:(1)Establish a full-size model of the rotating band engraving process of the revolving automatic mechanical system,theoretically analyze and calculate the force of the rotating band,the stress of the revolving bushing and the gun barrel bushing during the rotating band engraving process,based on Archard theory deduced the theoretical calculation formula of rifling wear.(2)Establish a finite element model of the engraving process,and directly apply the measured pressure on the bottom of the projectile as the driving force of the projectile.The comparison of the rotating band after the engraving is complete is correspond with the score of the recovered projectile;The relationship between the acceleration,velocity and displace-ment of the finite element simulation results are basically correspond with the measured values,which proves the accuracy of the finite element model.(3)Change the borehole angle of the revolving bushing,and analyze the stress,strain and temperature changes of the rotating band engraving into the revolving bushing.Because the revolving automatic machine has 2 bushes,these 2 bushes is not possible to achieve complete alignment at the junction.Analyze the rifling height difference and rifling circumferential alignment error to the stress,strain and temperature changes of the gun barrel bushing during the engraving process(4)Considering the different thermal properties of the materials of the Cr layer and the steel substrate,based on the Archard theory,the theoretical wear value of the rifling stress was calculated based on the previous stress,velocity.the theoretical calculated value and the measured value of the gun-barrel wear is very close,which indicates the correctness of the wear theory.According to the above studies on the elasticity of the rotating band,the rifling wear rule of the revolving automatic mechanical body tube bushing was obtained.It provides a reference for researchers to design the size of the rotating band and rifling.This study has a significant engineering value.