| In order to provide reference for the design and optimization of 84 mm recoilless gun weapon system,the interior ballistic solution and optimization design of recoilless gun,the dynamic unbalance of recoilless gun and the movement of firing system of recoilless gun were studied based on theoretical analysis,numerical simulation and experiments.Aiming at the interior ballistic design of recoilless weapon system,based on the classic interior ballistics mathematical model for recoilless gun,the interior ballistics calculation program was compiled by MATLAB software to study the interior ballistics of recoilless gun,and the parameters such as adiabatic index,burning rate constant,coefficient of second work,powder force and flow correction factor were optimized and modified using genetic algorithm.The optimized maximum chamber pressure and initial velocity were in good agreement with the experiment,which improved the accuracy and predictability of the interior ballistic program.The influence on the interior ballistic performance of recoilless gun was analyzed and summarized from the aspects of amount of propellant charge,chamber volume,projectile mass,powder force and nozzle throat area.The relation curve between interior ballistic pressure and velocity and time corresponding to each design parameter was obtained.The research results show that the influence of amount of propellant charge,chamber volume,powder force and nozzle throat area on the maximum pressure was greater than that on the initial velocity of the projectile,while the influence of the projectile mass on the initial velocity was greater than that on the maximum pressure.Therefore,when the interior ballistic design of recoilless gun is carried out,the design parameters could be adjusted according to the tactual and technical index requirements and the above results.On the multi-objective optimization design of interior ballistic of recoilless gun,the Pareto genetic algorithm was combined with the interior ballistics mathematical model of recoilless gun,and the optimization model of interior ballistics of recoilless gun based on Pareto genetic algorithm was established,and the multi-objective optimization design method of interior ballistics of recoilless gun based on Pareto genetic algorithm was proposed.The combination of interior ballistic design parameters under certain constraints was obtained,and the initial velocity of the recoilless gun could be increased by 3.8% under the condition that the maximum chamber pressure is basically constant.The designer could choose the best scheme of interior ballistic according to their needs,and the designer could also use this method to improve the interior ballistic performance of recoilless gun.For the study of the dynamic unbalance process of recoilless gun,the aerodynamic model was introduced,and the dynamic unbalance equation of recoilless gun during launch was established,which was solved by coupling the interior ballistics mathematical model with MATLAB.The influence of the major design parameters on the dynamic unbalance of recoilless gun was analyzed and studied,and obtains the relationship curve between the axial forces and the design parameter.The results show that the axial force of the nozzle,the axial force of the bullet ramp and the axial force of the barrel assembly decrease with the increase of the nozzle area,which was manifested in the reduction of recoil.The increase of rifling angle of barrel,inertia radius of projectile and friction coefficient between projectile and barrel assembly increased the axial force of projectile on barrel assembly,which is manifested in the reduction of forward moving.However,the increase of the chamber front sectional area increased the axial force acting on the bullet ramp,which was manifested in the reduction of forward moving.The projectile shot-start pressure affected the variation trend and consistency of nozzle axial force,bullet ramp axial force,barrel assembly axial force and barrel assembly unbalanced force,which was manifested in the reduction of forward moving,but the increase range was small.Therefore,when designing or testing the dynamic unbalance of recoilless gun,the above factors could be taken into account to effectively improve the efficiency and performance of the dynamic imbalance design of recoilless gun.Aiming at the problem of whether the firing system of recoilless gun weapon could fire the primer safely and reliably,the software ADAMS was used to simulate the firing system of recoilless gun weapon system,and the software ANSYS / LS-DYNA was used to simulate the dynamic process of the hammer impacting the firing pin.The dynamic characteristics of the hammer and its impacting the firing pin of firing system were obtained.The kinetic energy in front of the hammer impacting firing pin was 1.41 J.when the connecting rod was made of7020 aluminum alloy,the kinetic energy when the firing pin striked the primer was 0.31 J.when the connecting rod was made of 35 Cr Mn Si A,the kinetic energy when the pin strikes the primer was 0.25 J.The simulation results were compared with the high-speed photography test results,which verify the reliability of the firing system,and the energy conversion of firing process was analyzed.The results show that when the material of the connecting rod of the firing system was 7020 aluminum alloy and 35 Cr Mn Si A,the energy in the process of striking the firing pin by the hammer was converted by 21.99% and 17.73% respectively. |
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