Research On The Impact Of Bullets And Fragments On The Fuze And Related Insensitivity Technology

In order to improve the design of insensitive fuze,the response and laws of fuze under the impact of bullet and fragment are studied.Simulation software is used to study penetration process of different cartridges for insensitive munition bullet impact test home and abroad and initiation of fuze by fragment impact.The test projectile for insensitive munition fragment impact test is designed.In insensitive munition bullet impact test,the cartridge may penetrate through projectile body into main charge or penetrate the fuze body into lead explosive or booster explosive.In order to study the effect of different cartridges for insensitive munition bullet impact test,domestic 12.7 mm armor-piercing incendiary cartridge and American M2 armor-piercing cartridge are used to impact target plate of 45 steel with different thicknesses at different attack angles using ANSYS/LS-DYNA simulation software.The residual kinetic energy after cartridges penetrating the target plate is used as indicator of energy entering lead explosive,booster explosive or principal charge.The residual kinetic energy of domestic 12.7 mm armor-piercing incendiary cartridge and American M2 armor-piercing cartridge under different conditions is compared.Simulation results show that the residual kinetic energy of domestic 12.7 mm armor-piercing incendiary cartridge with velocity above 834 m/s and rotational speed is greater than that of American M2 armor-piercing cartridge with velocity of 850 m/s and rotational speed after penetrating 45 steel target plate of different thicknesses when attack angles are less than 5 degrees.So,it is feasible but potentially conservative to use domestic 12.7 mm armor-piercing incendiary cartridge with velocity above 834 m/s instead of American M2 armor-piercing cartridge for insensitive munition bullet impact test.In order to design insensitive fuze,the response characteristics of fuze under fragment impact is studied.ANSYS/LS-DYNA is used to simulate fragment impact with different impacting positions,different thicknesses of booster cup,different length of booster explosive,different types of booster explosive and different impact angles.Simulation results show incident blast wave propagates and forms reflected wave on the other side of booster explosive.The superposition of incident blast and reflected wave leads to detonation of fuze.The critical initiating velocity changes with the variation of impact point and booster explosive type.The critical initiating velocity increases with the increase of booster cup thickness and the length of booster explosive.When impact angle of the fragment increases from 0° to 40°,the critical initiating velocity increases with the increase of impact angle.The most dangerous position should be focused on when conducting improvement and protection of fuze.Increasing the thickness of booster cup and choosing appropriate insensitive booster explosive are considered to improve insensitivity of the fuze.In order to ensure that velocity of fragment reaches 2530±90 m/s according to STANAG 4496 requirement,the test projectile for insensitive munition fragment impact test is designed.The launching platform is 35 mm anti-aircraft gun.Standard case and artillery primer of 35 mm anti-aircraft gun are used.Calculated using classical interior ballistics theory,the muzzle velocity of test projectile reaches 2530 m/s when the propellant is 4/7 Shi and the charge mass is 208 g.Artillery tube,artillery carriage and recoil device meet strength requirements based on calculating using the artillery strength formula.The projectile sabot meets strength requirement during launching stage according to ANSYS/LS-DYNA simulation.Th projectile sabot can separate from fragment and does not affect flight of the fragment.The test projectile for insensitive munition fragmentation impact test meets test requirements.