Thermal/Structural Response Analysis Of Chromium-plated Gun Barrel And Its Effect On Bore Damage

The gun barrel is prone to be failure in working process because of the ablation damage and crack propagation in the barrel,which is caused by gunpowder gas pressure,warhead insertion force,resistance of guide side and high temperature.So it is important to discuss the effect of the response of the chromium-plated barrel during working process and the influence of temperature and stress on the damage of the barrel bore,which is of great significance to improve the barrel structure and technology of the barrel and to prolong the service life.The paper takes a small caliber rifle barrel as the research project,and the transient heat conduction,thermal structure coupling response and the interior of the barrel in the process of warhead extrusion are deeply studied by means of the heat conduction theory,the thermal structure coupling analysis theory,the extrusion resistance theory and the crack propagation theory.The damage of inner bore of chromium-plated gun barrel is also analyzed from the aspect of the mechanics,and it combines MATLAB programming technology with ANSYS/LS-DYNA finite element numerical simulation.The following are the research contents and results:The theoretical model of heat conduction of chromium-plated gun barrel is studied and established.The temperature distribution of chromium-plated gun barrel is calculated by using MATLAB software based on finite difference method.The temperature variation law of the inner surface,chromium-steel interface,half wall thickness and outer surface of gun barrel under single and continuous firing is analyzed.The theoretical model and finite element simulation model of thermal structure coupling analysis of chromium-plated gun barrel are studied and established.The stress and displacement of the barrel wall under temperature and bore pressure load are calculated.Thestress and displacement variation law of the chromium layer and the surface of the base material of the barrel under single and continuous firing are analyzed.The stress,strain and deformation of the barrel in the process of warhead extrusion are studied,and the finite element simulation model of warhead extrusion is established.The stress,strain and deformation of the barrel at the positions of the ramp,negative and positive lines are analyzed and compared.Based on the analysis of thermal/structural response of chromium-plated barrel,the variation law of barrel material strength under single and continuous firing conditions is further studied and determined.The influence of thermo-mechanical coupling and warhead extrusion on the damage of barrel bore is emphatically analyzed.According to the theory of crack propagation,the stress intensity factor and J integral value of crack in barrel bore under different pressure and temperature are calculated.Comparing the results,the propagation law of crack in inner bore under different bore pressure and temperature is obtained.Through the research,many laws and conclusions with practical significance have been obtained.The research results also provide a reference for improving the barrel structure and technology,and have important engineering practical value.