Study On The Characteristics Of Key Connection Parts Of Large Diameter Gun

Artillery is a complex structure system and its firing is a complicated process of high temperature, high pressure, high speed and high acceleration. In firing, the main parts of the artillery are subjected to large impact load, and the connecting parts of each component are also subjected to the enormous force. At the same time, the connecting parts affect artillery’s dynamic response. Therefore it is necessary to analyze the property of the connecting parts of the artillery, and study their effect on the dynamic response of the artillery.This thesis took saddle ring and elevating equilibrator of a vehicle mounted artillery as research objects, researched on their stiffness, and analyzed their influence on firing accuracy. The main research contents are as follows:(l)This thesis summarized the role of saddle ring in the artillery system. Based on the Hertz contact theory, considering saddle ring clearance, the relationship between the deformation and load was derived, and then got the analytical solution of saddle ring’s stiffness. Built a saddle ring finite element model to get the numerical solution of saddle ring’s stiffness and compared the analytical solution and numerical solution to reveal the nonlinear laws of saddle ring’s stiffness.(2)The composition and working principle of the hydro-pneumatic elevating equilibrator were summarized. In order to get the analytical solution of elevating equilibrator’s stiffness, an equivalent calculation formula was deduced, which neglected the elastic deformation of cylinder. A fluid-solid coupling finite element model of elevating equilibrator was formulated, which considered the compressibility of the fluid, the elastic deformation of the solid and the interaction between fluid and solid. By calculating the numerical solution of the stiffness of elevating equilibrator, and comparing with the analytical solution of the stiffness, the nonlinear laws of elevating equilibrator’s stiffness was revealed.(3)The basic knowledge of nonlinear dynamic finite element was described, which laid a theoretical foundation for the finite element modeling and analysis of artillery firing dynamics. The parameterized projectile-barrel coupling dynamic finite element model of a vehicle mounted artillery considering contact-impact between the projectile and the pipe’s rifling was established. Respectively with one of each direction saddle ring’s stiffness and elevating equilibrator’s stiffness as a variable, the others as constant, analyzed the influence of stiffness change to initial disturbance of projectile.(4)Through the sensitivity analysis, this stiffness was founded, which has great influence on initial disturbance of projectile. Parameterized the structure dimension of saddle ring and the stiffness of elevating equilibrator, then created the functions approximation models to replace the fire dynamics model based on FEM projectile-barrel coupling to optimize regarding minimal initial disturbance of projectile as objective, and got the structure dimension of saddle ring and the stiffness of elevating equilibrator, which are beneficial to reduce the initial disturbance of projectile.The above research has certain reference value for the design of the large caliber artillery connecting part and improvement of the artillery firing precision.