Analysis And Research On The Dynamic Characteristics Of A Thin-walled Barrel

The chamber pressure of the recoilless gun is low,so the thickness of the barrel is thinner than general guns.It is significant to study the dynamic characteristics of the thin barrel during launch which can help us to analyze its rigidity,intensity and firing intensity.The main contents of this paper are as follows:Firstly,the internal ballistic model of the smooth barrel recoilless gun,which launches turbine empennage projectile,is improved,and the calculated results are close to the experimental results.In order to obtain the rotating speed of the projectile when moving in the barrel,the rotating speed formula of the projectile is derived by imitating the rotating speed analysis method of turbine blade.The work provides necessary data preparation for the follow-up study.Secondly,the finite element model of coupling between the barrel,chamber pressure and projectile is established.It is used to analyze the stress distribution and stress amplitude of the barrel during the launching process.The paper also tries to use titanium alloy material instead of the original gun-steel material and use the idea of genetic algorithm to optimize the size of the barrel to reduce the quality of the barrel.The results show that the stress value of the barrel does not exceed the yield limit of the material,and the stress distribution is at the end of the barrel.Titanium alloy body tube can withstand the same load,which is applied to the gun-steel barrel,and have better performance.The volume and quality of the barrel is obviously reduced because of the size optimization in the secondary development program of Abaqus written by Python.Then,the barrel is similar to a cantilever beam model under moving loads and the merits and demerits of two models,Euler-Bernoulli beam and Timoshenko beam,used in the short and thin barrel in this study are discussed.The results show that the vibration characteristic of Timoshenko beam model,which considers shear deformation and moment of inertia,is closer to the solution of finite element method than that of Euler-Bernoulli beam model.After that,Timoshenko beam model was used to analyze the influence of the barrel vibration,which is at different center position of projectile mass,so as to provide a reference for controlling center position range reasonably.Finally,considering that recoilless gun fired by soldier's arm,a multi-body launch dynamics model of arm-barrel-projectile is established.This model is used to analyze the disturbance of projectile,which is influenced by center position of projectile mass And the holding gun posture by soldiers is optimized.After optimization,the disturbance of the projectile outside the muzzle becomes smaller,which improves the density performance of the recoilless gun.In addition,the difference between rifling barrel and smooth barrel is compared and it proves the smooth barrel is superior to the rifling barrel.