Excessive recoil severely restricts the loading of high-power traditional guns on modern vehicles. To reduce the recoil without breaking the continuous firing mode and reducing the projectile velocity, a recoil reduction method that controls the lateral ejecting of propellant gas by a piston was proposed. The recoil reduction device is symmetric about the barrel axis. First, a one-dimensional two-phase flow model of interior ballistic during the gun firing cycle was established. Next, the MacCormack scheme was used to simulate, and the piston motion was gained. Then the propagation of the rarefaction wave in the barrel was presented. Finally, the propulsion difference between the piston-controlled gun and the traditional gun was discussed. The results showed that the recoil momentum was reduced by 31.80%, and the muzzle velocity was decreased by just 1.30% under the reasonable matching of structural parameters.

To study the dynamic performance of a grenade machine gun system with soft recoil technology and analyze the floating mechanism parameters affecting the firing dispersion, a rigid-flexible coupling multi-body dynamics model was established. A twenty-round firing process of the grenade machine gun system was simulated and analyzed. The firing dispersion of the grenade machine gun system was obtained based on the external ballistics model, and the simulation model was validated by comparing the numerical results with the experimental data. The effects of the floating mechanism parameters on the cradle force, the projectile dispersion, and the firing dispersion sparsity were discussed. The results show that the projectile dispersion of the GMG system is well predicted by the simulation model, and the floating parameters that are matched reasonably could improve the firing dispersion and reduce the gun recoil force.

A new recoil reduction method of gun was proposed in this work to reduce the recoil without reducing the muzzle velocity and changing the continuous firing mode. Its recoil reduction mechanism was studied based on the two-phase flow theory. First, combining the gas-solid two-phase flow in the barrel, the electromagnetic control in the electromagnetic valve, the fluid-solid coupling in the piston cavity, and the transient gas flow in the exhaust pipe, an eight-stage mathematical model of the gun propulsion process was established. Next, the propagation law of the rarefaction wave in the barrel was discussed. Then, the propulsion difference between the gun proposed here and the traditional gun was presented. The results showed that the proposed method could reduce the recoil impulse by 38.20% without reducing the muzzle velocity under reasonable matching of the structural parameters.

The dynamic vibration absorber (DVA) has a broad application background in slender structure vibration reduction, such as in machine gun systems, micro actuators, and so on. Rapid modeling and simulation of the DVA-beam system are of great importance for dynamic performance, evaluation, and finally, the structural design. The primary motivation for this paper is to present a reliable and convenient technique for the modeling and computation of the DVA-beam system. A novel DVA-beam element, which consists of a beam segment and a DVA, is presented. In this element, the DVA position can be arbitrarily allocated, whether on the beam node or within the beam domain. In this way, the beam can be modeled with a few elements to save on computing costs and maintain ideal modeling accuracy. An element deactivating method, which endows the DVA-beam element with the ability to simulate a bare beam and a DVA-beam structure simultaneously, is proposed. Some numerical examples were carried out to validate the reliability of the DVA-beam element in addressing different kinds of boundary conditions by comparing the beam tip responses with those simulated by ADAMS software, and good agreements were observed. Finally, two DVA optimization examples were conducted to investigate the effectiveness and applicability of the DVA-beam element in engineering optimization. The performance was impressive.

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