Research and optimization of the firing rate of the firing mechanism of a long-range mortar howitzer fuse at small falling angles

To solve the problem on the effect of small drop angles of the mortar shells on the firing rate of trigger fuses and to improve the firing rate of trigger fuses, the small drop angle firing rate of the trigger fuse firing mechanism was examined using Monte Carlo simulation and optimization methods. A multi-rigid body dynamic virtual prototype model of the firing mechanism was established considering factors such as the pretension force of the ballistic safety spring, rotor mass, rotor seat mass, and firing pin height. A simulation system model for the triggering performance of the fuse was established, and when projectiles with different drop velocities hit the ground at small drop angles of 5 ~ 10°, the load on the fuse was examined. Second, when the projectile hit the target at small drop angles, the firing results of the fuse firing mechanism were obtained using ADAMS kinematic simulation. The critical dimensions of the key components, the preload force of the ballistic safety spring, the mass of the rotor, and the mass of the rotor seat were used as independent variables to evaluate the firing probability. The contribution of the variables that affect the target value was obtained through experimental design, and variable optimization was carried out for non-fire situations to ensure reliable firing of the independent variables within their allowable range. The results showed that when a projectile hit a target medium with a small drop angle, the spring pretension force and the mass of the inertial body were the key factors affecting the firing rate of the fuse. At a drop angle of 5°, the firing rate increased from 45.85% to 100%; at a drop angle of 7°, the firing rate increased from 73.34% to 100%; at an angle of 8°, the firing rate increased from 49.09% to 99.9%; and at an angle of 10°, the firing rate increased from 78.33% to 100%. Therefore, this research method could improve the ground wiping effect rate of mechanical triggering fuses and the effect rate of fuse triggering mechanisms. These results provide an important reference for combat screening and fuse design.