Impulse thruster is a kind of actuator used for trajectory correction or attitude control of some in-flight munitions and vehicles.A simple mathematical model was set up to model interior characteristics of an impulse...Impulse thruster is a kind of actuator used for trajectory correction or attitude control of some in-flight munitions and vehicles.A simple mathematical model was set up to model interior characteristics of an impulse thruster.With this model,effects of some key parameters on interior performances of the impulse thruster were studied.Results show that action time is affected significantly by nozzle throat diameter and volume of combustion chamber,while output impulse is sensitive to charge particle diameter and nozzle throat diameter.Through numerical calculation,the ranges of the optimized values for some key parameters were obtained.展开更多
In this paper,the influences of bore damage on the bullet-barrel interaction process and the mechanism of how bore damage results in the end of a machine gun barrel’s service life were studied,which had seldom been p...In this paper,the influences of bore damage on the bullet-barrel interaction process and the mechanism of how bore damage results in the end of a machine gun barrel’s service life were studied,which had seldom been paid attention to in the past several decades.A novel finite element mesh generation method for the damaged barrel and a new transient coupled thermo-mechanical finite element(FE)model,which were based on the damage data obtained through barrel life tests,were developed to simulate the interior ballistics process of a coupled bullet-barrel system.Additionally,user subroutine VUAMP was developed in the FE model in order to take the bullet base pressure brought by propellant gas into account.Good consistency between the simulation results and the experimental results verified the preciseness of the proposed mesh generation method and the FE model.The simulation results show that the increase of bullet’s initial disturbance at the muzzle and the variation of its surface morphology caused by bore damage are primarily responsible for the life end of this 12.7 mm machine gun barrel.展开更多
基金Sponsored by the Ministerial Level Advanced Research Foundation(51305080302)
文摘Impulse thruster is a kind of actuator used for trajectory correction or attitude control of some in-flight munitions and vehicles.A simple mathematical model was set up to model interior characteristics of an impulse thruster.With this model,effects of some key parameters on interior performances of the impulse thruster were studied.Results show that action time is affected significantly by nozzle throat diameter and volume of combustion chamber,while output impulse is sensitive to charge particle diameter and nozzle throat diameter.Through numerical calculation,the ranges of the optimized values for some key parameters were obtained.
基金supported by the National Natural Science Foundation of China(grant number 11802138)the China Postdoctoral Science Foundation(grant number 2018T110503)the Fundamental Research Funds for the Central Universities(grant number 30918011302)
文摘In this paper,the influences of bore damage on the bullet-barrel interaction process and the mechanism of how bore damage results in the end of a machine gun barrel’s service life were studied,which had seldom been paid attention to in the past several decades.A novel finite element mesh generation method for the damaged barrel and a new transient coupled thermo-mechanical finite element(FE)model,which were based on the damage data obtained through barrel life tests,were developed to simulate the interior ballistics process of a coupled bullet-barrel system.Additionally,user subroutine VUAMP was developed in the FE model in order to take the bullet base pressure brought by propellant gas into account.Good consistency between the simulation results and the experimental results verified the preciseness of the proposed mesh generation method and the FE model.The simulation results show that the increase of bullet’s initial disturbance at the muzzle and the variation of its surface morphology caused by bore damage are primarily responsible for the life end of this 12.7 mm machine gun barrel.
