As an important component of aircraft guidance system, non-metal radomes have multiple functions such as heat protection, wave transmission and load bearing. It is connected to the aircraft body through high-temperature resistant adhesive agent. Radome is frequently subjected to harsh mechanical and thermal loads during the period of service, and the joint structure is often the weakness of strength design. Therefore, accurate simulation for mechanical behavior of the joint structure and achieving accurate prediction of load-carrying capacity are crucial for the structural design and optimization of radome. Based on bilinear cohesive model, the failure behavior of radome adhesive interface is numerically described by ABAQUS. And then the damage evolution of adhesive layer is simulated, and the accurate prediction of bearing performance of radome joint structure under flight thermo-mechanical environment is achieved. The corresponding experimental study is carried out. The experimental results are in good agreement with the simulated ones, verifying the validity of numerical method. It provides an effective way to solve bearing problem of aircraft-level radome joint structure.

Aerodynamic heating is a key issue in the research of hypersonic vehicles flying in near-space. It has an important influence on the aerodynamic, thermal environment and safety of the aircraft. Due to the limitation of experimental methods, wind tunnel experiments cannot simulate real flight conditions accurately. CFD is an important tool for studying aerothermodynamics problems. The format dissipativeness and grid are two important factors that affect aerothermodynamics simulation. The smaller the format dissipation, the better the CFD performance, but low dissipation will cause shock instability phenomena. A hybrid HLLCE format which has both the HLLE format stability and the low dissipativity of the HLLC format is constructed. This format exhibits the low dissipation properties of HLLC at a lower Mach number and can overcome shock instability phenomena at high speed. The thickness of the linear bottom layer of the boundary layer is used as the reference scale, and 1/10 of the thickness of the linear bottom layer calculated by the feature length is taken as the minimum grid scale for thermal environment calculation. The performance of low dissipation scheme is verified by hypersonic sphere example with the proposed grid scale

Interstage thermal separation is one of the core technologies in the flight process of solid rocket. The traditional "three in one" test usually includes three main subsystems: upper stage motor, servomechanism and separation system. For practical engineering development, it is costly, expensive and long cycle. It can only be used for system level performance verification test, and is not suitable for exploratory developmental test. Based on the new ground test method of cold air simulated rocket interstage separation test, combined with theoretical model, numerical simulation and ground test verification, the internal flow field in the initial pressure holding stage of interstage separation is simulated, the law of gas pressure change in interstage section is revealed, and the test mechanism of cold air simulated rocket interstage separation is expounded; Through numerical simulation analysis, the effects of different initial pressure of pressure accumulator, different volume of pressure accumulator, different pipe area and different volume of interstage section on the change of gas pressure are studied, which provides a solution for the design of interstage separation test of cold air simulation.

A modular hierarchical power supply and distribution method is proposed for electrical system of launch vehicles in order to avoid large scale power supply cable, complex topology and potential path. Each stage of electrical system is planned as an independent power supply and distribution unit, and the integrated power supply and distribution framework is realized in the unit. Electrical isolation is designed among different power supply and distribution units and ground equipment to prevent the electrical coupling and potential circle path and reduce the system complexity. The power and distribution system has the advantage of modularization in system level and the plug and play with units, which provides a technical basis for the standardized design of the power supply and distribution structure of the future electrical system and hierarchical test of the launch vehicle.

In order to control the riveting interference and minimize the damage of GFRP composite caused by riveting, it is necessary to study the influence trend of riveting squeeze force on the interference of ${\Phi4}\mathrm{\;{mm}}2\mathrm{A}{10}$ rivet. The dynamic riveting process and the interference of the rivet have been simulated by ABAQUS on the effects of diameter of pre-drilled hole and riveting squeeze force of ${\Phi4}\mathrm{\;{mm}}2\mathrm{A}{10}$ aluminum alloy rivet on GFRP composite and aluminum alloy layers. On the basis of the simulation the experimental investigations are performed. The Interference test and metallographic analysis of the specimens are conducted. Results indicate that the interference of the same measurement location in the rivet increases with the increase of the riveting squeeze force and the interference with the same riveting squeeze force decreases through-the-thickness. ${\Phi4.2}\mathrm{\;{mm}}$ diameter of pre-drilled hole and ${18.3}\sim {18.7}\mathrm{{kN}}$ riveting squeeze force can achieve the optimum interference and the GFRP composite has no apparent injuries.

In order to improve test efficiency of launch vehicle and optimize the process of prelaunch testing, and to alter the traditional method of disconnecting electric cables manually for leakage monitoring, based on maintaining the original power supply circuit, a leakage monitoring technology research for the medium frequency alternating current supply circuit is proposed and developed. At the same time, the precision of leakage monitoring circuit is analyzed and the self-detection method is used to advance the reliability and safety of the system. The test results show that the system realized online leakage monitoring lasting no less than 24hours, and the range of leakage monitoring is 500 kΩ~50 kΩ with the precision better than ±10%, satisfying the monitoring requirements. Finally, the system experiment is carried out in the prelaunch testing of large cryogenic launch vehicle with high-reliability, high-precision and high-efficiency, and has significance of improving the level of automated testing and realizing unattended fore-end of launch vehicle.

With the development of data bus technology and the increasing demand for low-cost and high-reliability electrical systems in "flight-based transportation", Field Bus(FB) is gradually favored by the aerospace field. Controller Area Network(CAN), one of the most widely used field buses, has been researched and applied in missiles and tactical rockets. Considering the differences between launch vehicles and missiles, the application of CAN bus in launch vehicle control systems is expounded. The necessity of research is firstly analyzed, then typical CAN topologies suitable for medium and large-scale launch vehicles are given respectively. For the aim of practical use, two corresponding technologies are introduced which are the CAN relay technology and the CAN bus reconstruction. The efficiency and load rate of CAN bus are calculated which are then compared with the ones derived by 1553B data transmission under the same conditions. These results can be referenced by designers in a more accurate sense.

In response to the multiple ignition requirement of the expander cycle hydrogen-oxygen engine, research on the torch ignition system scheme is conducted, and a relatively reasonable low-pressure torch ignition system scheme is identified. The results show that the mixing ratio of the torch igniter fluctuated greatly when opening the hydrogen main valve, which may cause structural ablation. The scheme of introducing hydrogen from the inlet of the hydrogen turbine and liquid oxygen from the outlet of the liquid oxygen pump has a lower ablation risk, but it has a certain impact on the engine's start-up and steady-state characteristics. The low-pressure torch ignition start-up tests of liquid rocket engine are carried out for the first time in China. The experimental results verify the simulation results, and indicating the feasibility of the scheme.

In the fault-tolerant control of polyphase motors, hysteresis control is generally adopted for the more complex non-sinusoidal fault-tolerant current obtained by multi-constraint solving. Compared with hysteresis control, voltage space vector control has the advantages of low torque ripple and low energy consumption, which is more common in the control of polyphase motors. In order to solve the problem that the non-sinusoidal fault-tolerant current cannot be decoupled directly for voltage space vector control, Fourier transform is introduced and the non-sinusoidal fault-tolerant current is decomposed into fundamental current and third harmonic current to realize the decoupling transformation of the non-sinusoidal fault-tolerant current. Based on this, the decoupling transformation matrix is derived and the correctness of the processing method is verified by simulation analysis. The results show that this method can solve the problem that the non-sinusoidal fault-tolerant current under open fault-tolerant control of polyphase permanent magnet synchronous motor cannot be directly applied to voltage space vector control, so as to reduce the torque ripple and improve the motor current stability.

The stability of shipborne platform in complex sea surface wind and wave environments is an important foundation for the operation of shipborne equipment. Attitude stability control for shipborne platform, an active disturbance rejection controller is designed, which improves the tracking accuracy of the shipborne platform to the target angle, ensures the rapid response of the system, and suppresses the influence of uncertain factors such as wind wave disturbance and load disturbance. In order to further improve the control effect of the controller, the particle swarm optimization algorithm is used to optimize the intelligent parameters of the controller. The simulation results show that the ADRC can improve the tracking speed, accuracy and robustness of the system.