During the flight of aircraft, a coupling effect between the fluid aerodynamic forces and the structural elastomer will be formed, and this interaction may cause different degrees of damage to the divergence and jitter of the elastomer, resulting in safety risks. A numerical simulation method of fluid-structure coupling based on time-space conserved element solution and immersion boundary is proposed. The method of time-space conserved element solution is used to calculate the fluid domain, and the submerged body-fitted mesh boundary method is used to identify the fluid-structure coupling boundary surface. Taking NACA0018 as an example, the cloud image of wing outflow field pressure and velocity at different angles of attack is obtained through simulation data. At the same time, the buffeting amplitude of the wing under different inlet velocity and its rule are studied. The research shows that the fluid-structure coupling method has high accuracy and stability in solving high-speed compressible flows with complex flow patterns, including shock wave or detonation and large deformation problems, providing a reference research method for related research.

A 5B70 aluminum alloy sheet with ${1.5}\mathrm{\;{mm}}$ thickness is welded by tungsten inert gas (TIG) welding with 5B71 filler wire. The micro-structure evolution and refinement characteristics of the welded joints are investigated. The research results indicated that weld joints with excellent formation can be obtained by adopting reasonable welding parameters. The internal structure of the weld seam shows that the weld zone is mainly composed of equiaxed crystals forming a cast structure, the size of the grain structure is uneven, there are widely larger grains with a diameter of ${40}\sim {50\mu}\mathrm{m}$, as well as ultrafine grain areas with a diameter of about ${20\mu }\mathrm{m}$ which distributes in fine strips and small blocks. The area of the ultrafine grain region is obviously smaller than other areas. It mainly distributes in the direction parallel to the fusion line, with a few distributed on the weld surface. Sc and Zr were used as modificator to refine the grains. The ${\mathrm{{Al}}}_{3}\left({\mathrm{{Sc}},\mathrm{{Zr}}}\right)$ second phase particles are precipitated in the welding pool during solidification. The function of such particle is to form heterogeneous nucleation particles, reduce nucleation power and increase the number of crystal nuclei. The area where Sc elements are enriched had a higher degree of grain refinement. The “undercooling” zone is formed along the front of the solid-liquid boundary, which promotes the formation of equiaxed grains. It results in a higher degree of grain refinement, which size is only about one half of other zones.

To achieve attitude stability and depth control of a underwater vehicle, the dynamic characteristics and the influence of the tail rudders and sliding force on its dynamic characteristics are analyzed. The system is divided into three loops, and the controllers are designed for them. According to the damping characteristics of the system, pole placement is performed on the diagonal rate loop, followed by hysteresis correction on the overload loop based on the frequency domain characteristics of the system. Finally, the time domain characteristics of the depth loop are improved by adjusting the gain. Through simulation experiments, it has been verified that the control law designed can achieve attitude stability and depth control of a underwater vehicle, and has certain anti-interference ability. The linear control methods used in the article are common in engineering practice, and the calculation of controller parameters is based on the system's time-domain and frequency-domain performance indicators. The physical meaning is clear, and it has certain reference significance for engineering practice related to underwater vehicle attitude control.

An adaptive sliding mode control method for spacecraft with attack angle constraints is proposed based on a direct force/aerodynamic composite control strategy for agile maneuvering control at high angles of attack. Firstly, a longitudinal direct force/aerodynamic composite control model and a lateral jet interference model are established respectively. By designing a prescribed performance nonlinear mapping function, the attitude control problem of the missile body pitch channel with attack angle constraints can be transformed into an unconstrained angle of attack error adjustment control problem. Secondly, an attack angle error-based nonlinear integral sliding mode surface is designed. Under the framework of Backstepping control, an integral Backstepping sliding mode control method for adaptive estimation of lateral jet interference is proposed, in which the upper bound of lateral jet interference can be estimated online to achieve agile and accurate control. Finally, based on Lyapunov stability theory, the asymptotic stability of the designed closed-loop control system is analyzed. Numerical simulation results demonstrate that compared to the classical sliding mode control method, the proposed method reduces steady-state time by 79.16%, overshoot by 24.68%, and energy consumption by 34.54%.

Aiming at the active anti-interception game confrontation between hypersonic aircraft and accompanying defense aircraft to avoid interceptor attacks, an active defense intelligent guidance method for hypersonic aircraft is proposed based on deep reinforcement learning algorithm. In the case of insufficient maneuverability of the target aircraft, this method can achieve a higher success rate. Aiming at the sparse reward problem in the reinforcement learning training process, a reward function shaping method is proposed, which improves the convergence efficiency and training stability of the reinforcement learning algorithm. Finally, the effectiveness of the proposed method is verified by numerical simulation. The simulation results show that the proposed method can successfully achieve flight vehicle game confrontation, and has a higher game success rate than traditional game guidance methods.

Bistatic radar is widely used in military field by virtue of its good anti-jamming ability and accurate detection and identification ability, and how to effectively jam this transceiver-split radar system has become a current research hotspot. Typical jammers have large fluctuations of bistatic RCS with angle change and weak bistatic scattering strength, which are not advantageous in countering bistatic radar. Therefore, a new type of combined jammer against bistatic radar is proposed by analyzing the bistatic scattering characteristics of four types of typical jammers. Afterwards, electromagnetic simulation calculations are carried out on the new combined jammer monomer/array of different bands, sizes and spacings to study the bistatic scattering characteristics under different parameters, and compared with typical jammers. The results show that the new combined jammer monomer/array has strong bistatic scattering strength and the fluctuation amplitude of its RCS with respect to angle is smaller, with good bistatic scattering characteristics, providing technical support for effectively jamming of bistatic radar.

The theoretical development of weapon equipment system of systems engineering is reviewed from three aspects of the formation process of combat System of Systems, such as mutual reference relationship and connotation, research status of main links, intelligence, toughness and emergence, and the theoretical development of weapon equipment System of Systems engineering under the guidance of system engineering theory is summarized and analyzed. In the space field, the System of Systems project is the main carrier to carry out application exploration in two aspects of technology and management, based on which the future development direction is prospected.

In order to improve the efficiency of gas supply system in space launch, automatic charging technology of gas cylinders is proposed. Automatic charging schemes of gas cylinders based on PID control technology are designed, and the automatic control strategy is studied through the system simulation software AMESim. The results indicate that by setting the PID control module parameters reasonably, the schemes of gas charging can meet the automatic charging requirements of gas cylinders on launch vehicle. To improve the automatic charging control effect of gas cylinder, pressure sensor used in the control module should be installed close to the cylinders of launch vehicle.

The satellite-rocket interface is an important factor affecting the success of rapid response launches. Rapid response solid rocket is taken as the research object. On the basis of proposing the general requirements of the satellite-rocket interfaces for rapid response rocket, the satellite-rocket interface is analyzed focusing on mechanical interface and electrical interface, the optimal mode of satellite-rocket interface for rapid response rocket is explored. It is concluded that the memory alloy-driven point satellite-rocket connection unlocking device and wireless charging do not reserve a charging interface. The research provides suggestions on how to promote the use of optimal model of satellite rocket interface for rapid response rocket, and provides reference for improving the reliability and efficiency of rapid response launches.

In order to realize the unsupported launch of a medium-sized launch vehicle, a movable deflector scheme is adopted. Deflector has gone through a complete development process such as scheme design, gas flow field simulation analysis, metal matrix production, ablation test, heat protection cap production, etc., and has finally been successfully applied in the unsupported launch of medium-sized liquid launch vehicles.