Fuze An Aviation Related Technology Research Rocket Warhead Trigger

In order to further understand of the dynamic characteristics of contact fuze for some small caliber aircraft rocket projectile with the sideway inertial firing device when functioning at large falling angle and graze bursting, assess the satisfaction degree for the design index and provide reference for the design optimization and experiment. Firstly the aerodynamic characteristics of the projectile were simulated by FLUENT and the exterior ballistic characteristics in varieties of environment were simulated by MATLAB, which provided basic parameters for design and analysis of fuze. Then the target and ballistic environment’s influence on firing pin poking and the dynamic characteristics of the fuze sideway inertial firing device when graze bursting were researched by ANSYS. Finally fuze contact sensitivity, instantaneity and functioning reliability under various conditions were got through theoretical analysis, numerical simulation and experiment. The results indicate that:The average shape coefficient simulated is2.522. The drag coefficient is a quadratic function of the angle of yaw, increasing with the angle of yaw in subsonic. The angle of yaw coefficient which is a function of the Mach number can be acquired through fitting cures of the drag coefficient by the least square method, increasing with the Mach number, ranging from17.07to18.88and regarded as a constant.The method of drag coefficient curve fitting to calculate the exterior ballistic of fin-stabilized projectiles is come up with for the first time. The result is accurate. The error is within6.65%compared with the result by the classic shape coefficient method. Both methods can be applied in exterior ballistic calculation. The elements of trajectory are mainly determined by the armed helicopter’s cruising altitude and angle of departure, which are almost not affected by the armed helicopter’s cruising speed. The zero-lift drag coefficient of the projectile has nothing to do with the altitude below5000m. The ballistic difference between the plateau and the plain is mainly caused by the air density function.Both the instantaneity and the contact sensitivity of the fuze head stab firing mechanism are increasing with the target thickness when impacting thin targets. The fluctuations of the firing pin poking speed relative to the detonator are not the same as the change of target materials. When the projectile impacts soil, the firing pin can poke into detonator and the energy is enough to detonating detonator. So the functioning of the stab firing mechanism is guaranteed. From the standpoint of whether the firing pin can forward poke into the detonator, the fuze functioning is better with the firing pin movement guide, with which the fuze functioning is not guaranteed from the standpoint of the contact sensitivity and the functioning reliability. In addition, the fuze functioning is affected by the existence of the angle of yaw, but it can make sure the function at large falling angle.The contact sensitivity at small falling angle can be improved by properly increasing the quality of the sideway force ball and the half cone angle of the ball cap hole and the ball seat hole, and decreasing the spring force, the spring-firing pin system equivalent mass and the coefficient of friction between parts. Both the instantaneity and the contact sensitivity of the fuze sideway inertial firing device are increasing with the target thickness and the falling angle. The minimum fuze graze burst functioning falling angle is7°,which is smaller as the projectile falling speed is faster and the target becomes softer and thicker. The projectile impact attitude and the fuze functioning process are less affected by the projectile super-caliber fin, which may be associated with lower strength and stiffness of fin.