Abstract:In order to maintain good aerodynamic performance in both low and hypersonic velocity, related scholars took the advantages of the planform-controllable waverider and proposed the "vortex lift" waverider. This paper summarized the three types of vortex lift waveriders design method, namely the fixed leading edge profile method based on the osculating cone theory, the shock generating body method based on the shock-fitting method, and the projection method based on the given shock surface. The relevant research on the aerodynamic characteristics of the vortex lift waverider in the wide speed range was also reviewed, and some suggestions are put forward to the following research of vortex lift waveriders.

Abstract:The lattice structure is a periodic structure with a regular shape. It has the characteristics of high specific strength, high specific rigidity, light weight and high heat transfer efficiency. It is recognized as a structural material with wide application prospects. Applying the lattice structure to the active cooling technology to form a lattice active cooling structure is an effective means to solve the thermal protection problem of scramjet. The development of lattice structure is inseparable from the progress of preparation technology. This paper introduces the principle and research status of traditional machining technology and additive manufacturing technology, and summarizes the influence of the lattice structure unit, design size and the synergy with other structures on the heat transfer characteristics through literature research. On this basis, this paper analyzes the potential application value of the lattice sandwich active cooling structure in scramjet engines, and puts forward further development suggestions for its engineering applications.

Abstract:The Civil Aviation development of China rely on both the independent research of large transport aircraft and efficient air traffic management system. As the core part of ATC (Air Traffic Control), the fatigue detection and management of ATCs (air traffic controllers) is an important factor affecting aviation safety. In this paper, the recent research progresses on fatigue detection of ATCs are summarized detailly from the aspects of traditional subjective and objective evaluation, their advantages and disadvantages are analyzed in addition. Then, the extracting algorithms of ATCs fatigue feature based on speech analysis are described emphatically. Especially based on the background of artificial intelligence development in recent years, the deep learning model and detection algorithm are proposed to recognize speech fatigue better. Finally, the application prospect of fatigue detection is briefly described.

Abstract:This study set out to investigate the performance of morphing flap on dynamic stall alleviation. The unsteady flow field around the sinusoidally oscillating NACA 0012 airfoil are simulated by computational fluid dynamics (CFD) and dynamic mesh method. Two morphing flaps are compared with the rigid plain flap in terms of control effect and energy consumption. The numerical results show that, when the pulse signal of a sinusoidal shape is used, the flap deflection may be delay the formation of leading-edge vortex (LEV) and accelerate the development of the trailing-edge vortex (TEV). Meanwhile, the peak value of pressure distribution on the trailing-edge is reduced, and the large negative pitching moments are also decreased. The 2nd order morphing flap proposed in this paper could reduce the large negative pitching moment with the least energy requirement.

Abstract:Due to relaxed static stability are widely used in the field of advanced fighter aircraft design, in this paper, based on the related data of a certain type of advanced fighter aircraft, The influence of relaxation of static stability on the total pitching moment coefficient of this type of fighter is analyzed. A aircraft six degrees of freedom nonlinear mathematical model is constructed , whose open-loop characteristics which is effected by the relaxing static stability is analyzed .Secondly, the influence of the relaxed static stability on the aircraft motion equilibrium point is analyzed, and the nonlinear mathematical model of the aircraft is linearized based on the small disturbance theory. On this basis, the influence of the relaxed static stability on the step response characteristics and the long and short periodic mode characteristics of the longitudinal linear model of the aircraft is also analyzed .The influence of relaxed static stability on the longitudinal flight performance of aircraft is analyzed from the above multi-mode and multi-angle.

Abstract:The angle of attack and sideslip signal is an important parameter of the flight control system. According to the characteristics of the angle of attack sensors on both sides of the fuselage that are affected by the angle of sideslip, a pair of angle of attack sensors are used to calculate the angle of attack and sideslip.Wind tunnel tests were carried out on the front fuselage model of a large amphibious aircraft, and angle of attack sensors were installed symmetrically at both sides of the fuselageto study the variation of the measured values of the two sides of the angle of attack sensors with the angle of attack and sideslip angle of the model, the angles of attack and sideslip are calculated from the mean and difference of the measurements on the left and right sides. The scheme is verified by flight test. The preliminary flight test results show that it is feasible to calculate the angle of attack and sideslip angle by using the angle of attack sensors on the left and right sides of the fuselage.

Abstract:Lifting surface divergence plays an important role in static aeroelasticity analysis.Traditional static aeroelasticity analysis of airplane lifting surface makes the root part fixed without considering the influence of rigid mode. According to AC 25.629-1B, divergence may occur for a structural mode or the short period mode. Inertia relief method is studied and used to take rigid mode into account in divergence analysis. The method is used to compute the divergence results of empty airplane and different payload and fuel for certain airplane. Results are compared with that calculated by flutter method and mode method. Furthermore, results of empty airplane are compared with that gotten by SOL 144 of NASTRAN. Comparison shows divergence results with rigid mode are larger and divergence speed decreases with the increase of payload and fuel.

Abstract:Based on drag-reduction requirement, references involving with relation between drag and center-of-gravity(CG) were analyzed，and theoretic minimum-drag CG position expression was summarized. On this basis, the design of target CG for Active CG Control System was discussed with the consideration of tolerances in determination of aircraft CG. At last, the control strategy for Active CG Control was addressed by taking Airbus"s A340 as an example. The results show that it is not always as good as farther backward for minimum-drag CG. The target CG should be designed based on minimum-drag CG and tolerances during CG measuring, in which fuel plays a great role .By properly designing the fuel transfer threshold, a balance between drag-reduction, fuel-economy and alleviation workload for relating system/equipment could be struck.

Abstract:The perching maneuver is considered to be a feasible way to solve the problem of ultra-short landing of shipboard fixed-wing aircraft. Present research focuses on the aerodynamics modeling at high angle of attack, nominal perching trajectory optimization and perching trajectory tracking control, and lacks the overall analysis of landing mission. In this paper, based on the longitudinal perching dynamic model of aircraft, the concept of reachable set is introduced, and the mathematical description of reachable set is given. Then, the reachable set problem is divided into three trajectory optimization problems, which are the upper boundary of terminal altitude problem, the shortest trajectory problem at the certain terminal altitude, and the longest trajectory problem at the certain terminal altitude, and the corresponding mathematical models of trajectory optimization are given. At last, the trajectory optimization problems are solved by Gauss pseudo-spectral method, which has both high accuracy and efficiency. The simulation results indicate that the proposed optimization method is efficient, and the reachable set of perching trajectory for a glider is an asymmetric region with upper narrow and lower width, and the curve on the left and right boundary has good linearity. The relevant analysis conclusions can provide support and reference for the overall design of the perching task in the demonstration stage.

Abstract:The combination of the RF segment of the RNP procedure and the traditional ILS precision approach procedure can make full use of the advantages of the two types of procedures, but the transition phase of the two procedures needs to consider the design of the maximum descent angle. This paper analyzes the plane and section geometric design parameter limitations of the transition phase procedure, and analyzes the operating limitations of the transition from satellite-based navigation to ground-based radio navigation that require stable interception of heading signals and glide slope signals. Combining two types of limitations, this paper designs a method that can calculate the relationship between the deviation of the glide path and the arc distance to the final approach course fix point (FACF) from different final approach point (FAP) heights to determine the maximum descent angle. Through simulation verification, it is proved that the proposed method can calculate the maximum descent angle that meets the two types of limitations under the different transitional flight lengths and different final approach descent angles, and according to the given maximum program hypothetical temperature. This method provides a theoretical basis and feasible design method for the descending profile design of the transition between the RNP procedure and the ILS procedure, and can provide a reference for the actual design of this type of procedure.

Abstract:In order to perform specific missions, functional components should be towed by aircrafts, such as airborne trailing submarine communication antenna, etc. In these applications, the establishment of scientific models and methods to accurately analyze the steady and dynamic characteristics is a prerequisite to ensure the normal operation of the towed objects. Dynamic model considering aerodynamic force, inertia force, and elastic force of airborne antenna system is established and verified through published steady state results. Dynamic response of the antenna system under disturbance of aircraft unsteady motion and gust is studied, and the extreme conditions such as antenna fracture are evaluated. The results indicate that the analysis results of verticality and tension of the model established in this paper are good, which can be applied to the analysis of the steady and dynamic characteristics of air towed objects, and has engineering value in the design of submarine communication antenna, refueling pipe and other systems.

Abstract:According to the demand of the wind tunnel experiment, the aerodynamic force measurement technology using a distributed-sting-balance is developed. As an application instance, a twin-sting-balance measurement system with the function which can eliminate the internal stress of the system is carried out. Two Calibration methods for the six-component twin-sting-balance measurement system are used and discussed, which are the combination calibration method and the integration calibration method, and the verification of the reliability of the twin-sting-balance system design and the calibration methods are also conducted. The results show that the twin-sting-balance measurement system design can eliminate the inherent internal stress caused by the over-constraint of the system effectively. Besides, the twin-sting-balance system can obtain a high force measurement accuracy and precision using both of the two calibration methods, which can meet the requirement of the wind tunnel experiment. Finally, the wind tunnel experiment is conducted with the method of combination calibration taking into account the calibration capability of the calibration rig in CAAA, and a satisfying measurement precision is obtained.

Abstract:In the process of civil aircraft production, there will exist such a situation that the fasteners interfere with bend radius and it is hard to replace the structure element because of some limits of objective condition. When we utilize filler to fit radius, the fatigue quality of joints will be affected due to the change of stress concentration and the non-standard installation of fasteners. This article investigates the effect on DFR values of joints whose hi-lock bolt interferes with bend radius (parallel to load) utilizing filler to fit radius in civil aircraft by fatigue tests. During the design of test specimen ,we analyze the influence of some parameters on stress concentration factor by finite element method. Then we carry out 3 groups of fatigue tests according to the results of finite element analysis and get the corresponding DFR values’ correction factor. Comparing the fatigue test results with the results of engineering calculation method, we find that the failure mode of specimen is completely consistent and the difference of DFR values is within the reasonable range.

Abstract:In view of the situation that civil aircraft structure repair process will encounter beyond the scope of the manual, in order to provide relevant reference for maintenance engineers to develop repair plan, and quickly develop a reasonable repair plan, a civil aircraft structure repair plan platform based on B/S (Browser/service) is developed. Firstly, the platform requirements are analyzed from the perspective of business process and platform function. Then it introduces the technologies used in the platform development, and describes the platform design in detail from three aspects of platform architecture, database and platform function module. Finally, the main function modules of the platform are tested through the actual operation demonstration. The test results show that the platform has friendly man-machine interface, good expansibility, simple and convenient operation, realizes the electronization of civil aircraft structure damage information and repair scheme, and can automatically recommend several repair schemes stored in the database according to the damage information, which provides support for the maintenance engineering department to quickly formulate the repair scheme beyond the manual.

Abstract:The product structure of aero-engine is very complex and changes frequently, It is difficult to realize the real-time and accurate definition of design configuration by using the traditional parts list management mode or simply replacing the parts list with EBOM. In this paper, the configuration management experience of WZ16 engine and EC175 transmission systems was summarized, and the effectiveness configuration function of Teamcenter system was studied. From the perspective of facilitating model serialization development and configuration management, a single management method of aero-engine design configuration based on EBOM was proposed and verified during the configuration management process of one civil turboshaft engine. The preliminary result suggested that, it can effectively improve the control efficiency and accuracy of the design configuration.

Abstract:To effectively improve the ability of material application and management in aircraft parts designing，and ensure the rapid development of new aircraft designing. By analyzing the current state of material application in aircraft parts designing, the application problems in designing are pointed out, the technical contents have to focused and working procedure ought to followed that used for material selection and substituting are put forward. Furthermore, a technical management procedure about material selection and substituting that apply to the aircraft parts designing are established. Finally, the example of material selection for sealing materials of a certain military aircraft structure and the material substitution for conductive gasket in the electrical system prove the effectiveness of this method. At the same time, it will also provide relevant reference for related enterprises in the aviation field and other fields.

Abstract:Attitude and heading reference system（AHRS）is an important instrument used to measure，calculate and provide flight attitude and heading information. Its indication accuracy directly affects the pilot's control and the performance of autopilot. Aiming at the fault that the magnetic heading error of a certain type of heading and attitude reference system is too large in the test process，in this paper，the mechanism of the system is theoretically analyzed，the fault tree is established，and the bottom events are analyzed one by one through actual operation detection，so as to screen the cause of the problem，and successfully locate and eliminate the fault. The results show that：the reason of the large magnetic heading error of the AHRS is that the meaning of the variables is confused when the GPS signal is used to correct the output value. The design of the magnetic heading algorithm is not rigorous enough，which leads to large error. The fault tree analysis method can successfully locate and check the fault.

Abstract:In order to study the influence of rough surface characteristics on the leakage of the metal seal ring gap, a mathematical model of three-dimensional rough surface was established according to mathematical formulas, a micro rough surface was established with surface roughness as an evaluation index, and a leakage channel model was established after contact calculation using finite element method. , Using CFD technology to simulate and analyze the flow field inside the gap of different structures, get the flow field distribution and velocity distribution, and calculate the leakage rate of the sealing gap. The results show that as the height of the sealing gap decreases, the surface roughness value decreases, and the pressure difference between the inner and outer chambers decreases, the leakage rate of the sealing system gradually decreases.

Abstract:In the development process of civil aircraft，equipment qualification test used to verify the airborne device of aircraft targets meet and conformity of airworthiness terms A set of complete ground simulation test verification environment is proposed for civil aircraft qualification test, which supports the effective development of all test subjects and provides reliable and complete test evidence. The author of this article introduce the necessary of qualification test of civil aircraft flight control system and the main qualification test type, The key point is environment design ,including the main composed of the environment、the function of the environment、the test scheduling and the monitor logic. It provides reference for other Environment Design of Qualification Test in the future.

Abstract:DO-178C clearly requires that the software quality assurance (SQA) process must be included in the airborne software integration process as an acceptable compliance standard for airborne software airworthiness. Based on the software life cycle definition, process and data of airborne software, this paper analyzes the implementation of the software quality assurance process based on DO-178C from the three aspects of objectives, activities, and compliance review. With software project quality management techniques and tools, the DO-178C-based software quality management method is explored from the three processes of planning software quality management, managing software quality, and controlling software quality, and some practical engineering suggestions are given. By using both software quality assurance and quality management, evidence of airworthiness requirements can be generated to provide confidence in civilian airborne software that meets the requirements, effectively ensuring its quality and continuous improvement.