Chengxin Du

To address the challenges of discrete control and real-time decision-making for impulse-controlled vehicles, this study proposes a landing-point prediction and control algorithm based on a Bidirectional Long Short-Term Memory (Bi-LSTM) neural network. The algorithm employs the Bi-LSTM network to accurately predict the vehicle landing point in real time, and subsequently computes the vehicle–target deviation to determine the optimal impulse-ignition parameters. Simulation results demonstrate that the Bi-LSTM prediction model significantly outperforms traditional BP, LSTM, and GRU networks, achieving a final landing-point prediction error with a mean per-axis RMSE of 1.96 m (three-dimensional error norm of 3.87 m). Based on these prediction outcomes, two control strategies—“nearest-point ignition” and “ignition delay”—are compared. Monte Carlo experiments indicate that both strategies effectively enhance landing accuracy, with the nearest-point ignition strategy showing superior performance, reducing the circular error probable (CEP) from the uncontrolled 72.60 m and 124.82 m (at launch angles of 23° and 51°, respectively) to 7.20 m and 10.30 m. This study provides a high-precision, terminal-phase control solution for impulse-controlled vehicles, with implications for the low-cost onboard implementation of discrete impulse control.

To expand the application range of explosive fragmentation projectiles, tungsten fiber-reinforced bulk metallic glass matrix composite (WF/Zr-MG) is used as the warhead shell in static explosion experiments, and is compared with 40CrMnSiB steel shells. The experimental results showed that, compared with 40CrMnSiB steel shells, the fragments produced by the WF/Zr-MG shell exhibit a larger aspect ratio, smaller average size, and a greater number of fragments at distances of 3 m and 5 m, with an equal number of fragments at a distance of 8 m. Theoretical calculations showed that the initial velocity of the fragments produced by the WF/Zr-MG shell is lower, but their velocity decay is slower, resulting in a greater determined damage range. The research results showed that WF/Zr-MG can be used as a shell material for explosive fragmentation projectiles, which can enhance their destructive power.

To improve the tactical and technical performance of pulse correction projectiles while maintaining stability in uncertain conditions and considering practical engineering constraints, this study performs a multi-objective robust optimization design of the aerodynamic shape and external ballistics of a projectile. The study utilizes an aerodynamic force engineering algorithm and numerical trajectory calculations to obtain the projectile’s performance responses within the Latin hypercube design space. To enhance optimization efficiency, a stochastic Kriging surrogate model is established to capture the inherent uncertainty of limited input data. Ultimately, a Pareto optimal solution for the projectile is obtained using a non-dominated sorting multi-objective sparrow search algorithm. The results of this study demonstrate that the consideration of design uncertainty in the robust optimization of pulse correction projectiles leads to significant enhancements in both lateral correction ability and range while satisfying flight stability requirements. Moreover, when compared to deterministic optimization, the performance variability of the design is markedly improved. This research methodology provides valuable insights for optimizing the performance of pulse correction projectiles.

The finite element model of oblique penetration of short-rod projectile into a thin metal target was established and the effectiveness of the model was verified to study the oblique penetration law of short-rod projectile into a thin metal target. The simulation calculation of short-rod projectile penetrating thin metal targets with different obliquities at different impact velocities was carried out. The simulation results show that the critical ricochet velocity of the projectile increased with the increase of the obliquity of the target plate, as well as the increment of the critical ricochet velocity of the projectile. With the increase in the obliquity of the target plate, the ultimate penetration velocity of the projectile increases exponentially, and when the obliquity is large, the ultimate penetration velocity increases sharply. When the projectile ricocheted without invading the target, the velocity attenuation of the projectile increased with the increase of the impact velocity, whereas the mass of the residual projectile decreased. However, when the impact velocity exceeds the ultimate penetration velocity of the projectile to the target plate, the velocity attenuation of the projectile decreased and the mass of the residual projectile increased with the increase of the impact velocity. With the increase of impact velocity, the included angle decreased gradually, and the decreasing trend also slowed down. When the impact velocity was just greater than the ultimate penetration velocity, the included angle was the largest. At the same impact velocity, the greater the obliquity of the target plate, the greater the included angle. This study is of great significance to reveal the critical ricochet and ultimate penetration of projectile, the velocity, mass, and trajectory change in the process of penetration, as well as the damage of projectile to the target plate.

In order to adapt to the launch velocity of modern artillery, it is necessary to study the fracture mechanism of the high-velocity penetration of penetrators. Therefore, the penetration fracture mode of tungsten-fiber-reinforced Zr-based bulk metallic glass matrix composite (WF/Zr-MG) rods at a high velocity is studied. An experiment on WF/Zr-MG rods penetrating into rolled homogeneous armor steel (RHA) was carried out at 1470~1650 m/s. The experimental results show that the higher penetration ability of WF/Zr-MG rods not only results from their “self-sharpening” feature, but also due to the fact they have a longer quasi-steady penetration phase than tungsten alloy (WHA) rods. Above 1500 m/s, the penetration fracture mode of the WF/Zr-MG rod is the bending and backflow of tungsten fibers. Our theoretical calculation shows that the deformation mode of the Zr-based bulk metallic glass matrix (Zr-MG) is an important factor affecting the penetration fracture mode of the WF/Zr-MG rod. When the impact velocity increases from 1000 m/s to 1500 m/s, the deformation mode of Zr-MG changes from shear localization to non-Newtonian flow, leading to a change in the penetration fracture mode of the WF/Zr-MG rod from shear fracture to the bending and backflow of tungsten fibers.

A tungsten fiber/Zr-based bulk metallic glass matrix composite (Wf/Zr-MG) is a potential penetrator material. To compare and analyze the penetration behavior of Wf/Zr-MG and a tungsten heavy alloy (WHA), a penetration experiment into the 30CrMnMo homogeneous armor target plate (RHA) is conducted in the present paper, by using a 37 mm smooth bore artillery with an impact velocity of 1550 ± 40 m/s. Unlike the penetrator made of WHA, the self-sharpening phenomenon was observed in the nose of the Wf/Zr-MG rod. The experimental results indicate that the penetration ability of Wf/Zr-MG rod is approximately 10% higher than that of the WHA rod when the impact velocity is 1550 ± 40 m/s. The combined findings on the microscopic morphology, composition, hardness distribution around the crater, and the macroscopic structure of the penetrator residual show that under this impact velocity, the Wf/Zr-MG material shows amorphous gasification. The Wfs outside the rod shows bending and backflow, resulting in the maintenance of the self-sharpening nose of the penetrator during the penetration process. Moreover, the hardness peak around the crater formed by the Wf/Zr-MG rod is lower, and the penetration crater is straighter, indicating that the Wf/Zr-MG rod has a stronger slag removal ability, lower penetration resistance, and higher penetration efficiency. It is an ideal penetrator material.

In order to increase the penetration ability of tungsten fiber-reinforced Zr-based bulk metallic glasses matrix composite rod, two multi-diameter tungsten fiber-reinforced Zr-based bulk metallic glasses matrix composites (MD-WF/Zr-MG) are designed. In MD-WF/Zr-MG-I, the diameters of tungsten fiber (WF) increase gradually from the inside to outside, which is the opposite in MD-WF/Zr-MG-II. Penetration experiment of two kinds of MD-WF/Zr-MG rods into rolled homogeneous armor (RHA) steel target from 1470 m/s to 1630 m/s is conducted. The average penetration depth of the MD-WF/Zr-MG-II rod is higher than that of the MD-WF/Zr-MG-I rod. Penetration failure modes of MD-WF/Zr-MG-I and MD-WF/Zr-MG-II rods are bending, backflow of WFs and shear failure respectively. The failure mode of MD-WF/Zr-MG is affected by the bend spaces and the ultimate bending diameters of WFs. If the bend spaces of all WFs are equal or larger than their ultimate bending diameters, the penetration failure mode is the bending and backflow of WFs, oppositely the penetration failure mode is the shear failure. The MD-WF/Zr-MG rod with shear failure exhibits high penetration ability because of low penetration resistance and little residual material in the crater. When designing MD-WF/Zr-MG, bend spaces of a part of WFs should be smaller than their ultimate bending diameter to cause shear failure.