A Grenade Bottom Mechanical Trigger Fuze Technology Research

In order to provide ballistic environment for fuze design, the process of firing rifle grenade using5.8mm and7.62mm caliber bullet was simulated with the software ANSYS/LS-DYNA,and then the setback overload-time curve was obtained,and the peak of the setback overload was obtained through experiments using the copper cylinder pressure measuring principle,and this proved the result of simulation.The peak of the setback overload of firing rifle grenade using bullet is more than19000g,and it’s far higher than that of firing rifle grenade using blank.The time that firing rifle grenade using bullet is as short as120p.s,and it’s close to the time of impact when fuze dropping to steel plate from1.5m height.The setback overload of firing rifle grenade using7.62mm calber bullet is80%higher than that of firing rifle grenade using5.8mm caliber bullet.The setback overload is lower when the material of the bullet trap is softer,whereas higher.In order to find the differenece among the heights of the copper-cylinder pressed by parabolic pressure,triangular pressure and static pressure,and prove that the pre-pressure on copper-cylinder can improve the accuracy of the measurement of pressure,and get the curve of the height of copper-cylinder varied by pre-pressure,a simulation of the process that standard copper-cylinder was pressed by the three kinds of pressure as well as the process of copper-cylinder pre-pressured by different pressure was loaded by diferent load was carried with ANSYS/LS-DYNA.Then a conclusion is draw that the height of the copper-cylinder pressed by parabolic pressure is9.70%higher than that is pressed by static pressure,while the height of the copper-cylinder pressed by triangular pressure is18.22%higher than that is pressed by stastic pressure.And that the pre-pressure on copper-cylinder can improve the accuracy of the measurement of pressure is proved and explained,and the curve of the height of copper-cylinder varied by pre-pressure is obtained.The interior ballistics of rifle-grenade is calculated using the rifle-grenad classical interior ballistics theory., the relationship of velocity and acceleration with the movement time and displacement of the rifle-grenade was obtained. The time that gunpowder gas pressure continued is only as long as2ms when rifle-grenade is launched. Compared with7.62mm calber bullet, rifle-grenade launched using5.8mm calber bullet moves faster and the pressure in the bottom of rifle-grenade is biger.In accordance with the phenomenon that sometimes the rigid safety device in the rifle-grenade fuze can not be armed when the rifle-grenade is lanuched, through the simulation, a research is done in the relation between the hardness and the size of the bullet trap and the arming of the rigid safety in the rifle-grenade fuze. And a conclusion that the rigid safety is armed more easily when the bullet trap is harder and the front part of the bullet trap is longer is draw.The strength of the outer-splint of clock device in the fuze under high overload is simulated and analyzed. And in accordance with the phenomenon that a visibly deformation appears when the outer-splint is under high overload, a improved design in structure and fitting is proposed. Through the simulation proving, the improved design can decrease the deformation of the outer-splint under high overload.