Research On The Key Technology Of An Individual Soldier's Recoilless Grenade And Its Fuze

In order to provide reference for the development of a new medium-calibre recoilless gun HE projectile and it's fuze,the aerodynamics and exterior ballistic characteristics of the HE projectile,the change of the polar damping moment with eccentricity and dynamic unbalance angle in the case of mass asymmetric,the attenuation law of angular spin of the HE projectile in exterior ballistics and the influence of the fuze output power on the power of the HE projectile were studied by theoretical analysis,numerical simulation and experiment.In order to provide reference for the design of the HE projectile and its fuze,it's aerodynamic and exterior ballistic characteristics were studied by numerical simulation using FLUENT and MATLAB.The change law of the HE projectile resistance coefficient with Mach number and angle of attack is obtained.The resistance coefficient of the projectile is consistent with the trend of standard bullet resistance law and increases with the increase of attack angle.The equation of exterior ballistic centroid motion is properly transformed to a equation which can directly calculate exterior ballistic element by projectile resistance coefficient without ballistic coefficient.And through this equation,the exterior ballistic elements of the HE projectile under different angle of fire are obtained,and the result of the calculation is consistent with the experiment results.The effect of the tail shape on the resistance coefficient of subsonic projectile is studied,and proposed a scheme of tail shape improvement for the HE projectile,which can increase it's firing range by more than 12 percent.Through theoretical calculation,the projectile meets the conditions of gyro stability,follow stability and dynamic stability,and the projectile has flight stability.In order to study the effect of eccentricity and dynamic unbalance angle on the projectile's polar damping moment.First,based on the idea of Monte Carlo method,the eccentricity and mass distribution of the HE projectile were simulated by MATLAB programming.Through two million samples,the range of the eccentricity of the projectile is from 0 to 0.2 mm,which roughly matched the expected Rayleigh distribution of 0.04966 or Weibull distribution of0.05574,but failed the Kolmogorov-Smirnov test with a confidence level of 0.05.Then based on but not limited to the recoilless HE projectile,the range of the eccentricity of the projectile was extended to 1 mm.The influence of the eccentricity and the dynamic unbalance angle on the polar damping moment of the static unbalanced projectile and the dynamic unbalanced projectile were studied by FLUENT software.For static unbalanced projectiles,within the range of eccentricity of 1 mm,the polar damping moment coefficient and polar damping moment of the HE projectile increase as the eccentricity of the projectile increases.For a dynamic unbalance projectile,when the dynamic imbalance angle is constant,the polar damping moment coefficient becomes larger as the eccentric distance increases;when the eccentric distance is constant,the polar damping moment coefficient first increases and then decreases with the increase of the projectile unbalance angle.In order to obtain the attenuation law of angular velocity of the ellipsoid head projectile,which can provide a reference for the projectile distance test,based on aerodynamic theory,a mathematical model of the angular velocity decay of the exterior ballistics of the projectile was derived.The MATLAB software was used to calculate the HE projectile's exterior ballistic angular velocity decay curve and the exterior ballistic elements containing the revolution information.Through FLUENT simulation,the variation law of the projectile polar damping moment coefficient with the projectile speed and angular velocity was obtained.The result shows that when the angular velocity is constsnt,damping moment coefficient increases as the projectile speed decreases;when the projectile speed is constant,the projectile polar damping moment coefficient increases as the projectile angular velocity increases.The fitted equitation about ballistic pole damping moment coefficient and projectile's speed and angular velocity are substituted into the equation of centroid motion of the exterior ballistics.By comparison with the shooting range test data,it is found that the attenuation speed of the projectile speed obtained by the two methods is consistent with the actual situation,but the method derived by theory is more accurate.The effect of the eccentricity of the projectile on the attenuation of the speed was studied by the simulation method.Studies have shown that the difference of speed decay curve between the HE projectile with maximum eccentricity of0.2 mm and the projectile without eccentric is small.It shows that the existence of eccentricity has a certain impact on the speed decay law of the projectile,but because the maximum eccentricity of the HE projectile is only 0.2 mm,the effect of the eccentricity on the speed decay law of the HE projectile is not obvious.In order to provide a reference for the design of the HE projectile fuze for recoilless gun,the influence of the kind of booster and the materials,the wall thickness as well as the cone angle of the cavity liner in the fuze on the power of the HE projectile were studied using AUTODYN.The results show that the output power of the fuze has an impact on the size,number and speed of the fragments produced by the HE projectile,increasing the output power of the original design fuze can increase the power of the HE projectile.The method to increase the output power of the fuze can be to change the booster from RDX to HMX;change the material of the cavity liner in the fuze from high-conductivity oxygen-free copper to tungsten alloy;make the wall thickness of the cavity liner be about 0.8 mm and cone angle be about 100°.