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Sponsored by: Northwestern Polytechnical University  Chinese Society Aeronautics and Astronautics
Address: Aviation Building,Youyi Campus, Northwestern Polytechnical University
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    2024,15(2):1-10. DOI: 10.16615/j.cnki.1674-8190.2024.02.01
    Abstract:
    The emergence of Mars UAVs provides a new idea for Mars exploration and is an important paradigm for future deep space exploration. This paper compares the differences between Mars and some relevant surface environmental parameters on Earth, analyzes the main uses and the difficulties that Mars UAVs need to overcome, and clarifies the importance of Mars UAV experimental benches. The technical features and functional advantages and disadvantages of the Mars UAV experimental platform developed by domestic and foreign research institutions are introduced in detail, and the need for the experimental platform to have a simulated Mars environment and measure relevant parameters is summarized. On this basis, the idea of building a Mars UAV experiment platform is proposed, the overall design ideas and thoughts are given, and the prospect of the application of the Mars aerodynamics experimental platform is made.
    2024,15(2):11-24. DOI: 10.16615/j.cnki.1674-8190.2024.02.02
    Abstract:
    For near space unmanned aerial vehicles (NSUAVs), efficient power type is the key to support their long flights. It is considered that the “airborne liquid hydrogen storage + hydrogen fuel cell” scheme is in line with the trend of NSUAVs’ greater endurance and larger payloads. In allusion to this scheme, the technology status of hydrogen supply processes, airborne hydrogen tanks, air supply processes and water/heat management for fuel cells are summarized in this paper. Technical analysis and summaries are carried out on hydrogen delivery methods, structures and materials of airborne hydrogen tanks, as well as the influences of low pressure environment on the suction performance of air compressors and heat dissipation performance of fuel cells. The development direction of relevant technologies is also discussed, providing reference for later studies.
    2024,15(2):25-34. DOI: 10.16615/j.cnki.1674-8190.2024.02.03
    Abstract:
    Flow-induced noise is a common problem in practical engineering. The classical acoustic analogy model is insufficient to evaluate the characteristic distribution of the acoustic field using only acoustic pressure as a reference. This paper starts from a four-dimensional linear wave equation with sound pressure and sound velocity vectors as variables, by choosing the Kirchhoff surface to enclose a nonlinear acoustic source and combining with the convective Green"s function, the four-dimensional acoustic frequency-domain integral equation for a uniformly moving medium is developed. Numerical prediction studies were conducted for stationary, rotating monopole and dipole sources. The results indicate that the distributions of the sound pressure and acoustic velocity obtained by the present proposed method are in good agreement with the analytical solutions. In contrast to the stationary flow case, the acoustic field distribution of the stationary point source in the uniform flow exhibits a convection effect. On the other hand, the acoustic field distribution of the rotating point source exhibits a strong Doppler effect and convection effect due to the joint influence of the uniform flow, the self-excitation frequency, harmonic order, and rotational frequency of the point source. The refined study of aerodynamic vector noise with uniform flow in this paper can provide technical support for the assessment of acoustic energy and the prediction of transmission paths. Additionally, it provides a theoretical basis for noise reduction studies.
    2024,15(2):35-41. DOI: 10.16615/j.cnki.1674-8190.2024.02.04
    Abstract:
    The resistance characteristics of aero-engine high-altitude ice crystal particles will affect the movement of ice crystals. In order to explore the influence of different shapes of ice crystals on the drag coefficient, the paper adopts the method of high-speed camera tracking to investigate the drag coefficient of spherical particles and non-spherical particles (long cylinder, short cylinder and disk). The Reynolds number and drag coefficient of different particles are obtained according to the velocity of particles at uniform velocity, and the correlation formula for calculating drag coefficient of different particles in the working condition range is obtained by fitting experimental data. Finally, the correlation formula is verified by using experimental data other than fitting data. The results show that the Reynolds number ranges from 3961 to 24144. The average relative error between the calculated and experimental values of the four particle resistance coefficients is less than 5%.
    2024,15(2):42-48. DOI: 10.16615/j.cnki.1674-8190.2024.02.05
    Abstract:
    Aviation is one of the eight key industries of carbon emission. The carbon emission of aviation industry is mainly affected by the carbon emission of aero-engine. Therefore, it is urgent to carry out the research on the measurement method of aero-engine carbon emission. The life cycle assessment is used as a quantitative method for the carbon footprint of aero-engines. The life cycle carbon emissions of aero-engines are divided into fuel cycle carbon emissions and material cycle carbon emissions, and statistics are carried out separately. The aero-engine system boundary is divided, the data collection that should be carried out in each stage is proposed, and the data is required. This paper obtains a relatively complete set of aero-engine carbon emission measurement methods. This method comprehensively evaluates the carbon emissions of aeroengines from the perspective of life cycle, which can provide guidance for the measurement of carbon emissions of aeroengines throughout the life cycle, and provide a theoretical basis for emission reduction from the perspective of fuel and material.
    2024,15(2):49-55. DOI: 10.16615/j.cnki.1674-8190.2024.02.06
    Abstract:
    In the current research on the fatigue state of controllers using radiotelephony communication, most of them only consider the changes of voice in the time domain or frequency domain, while ignore that fatigue will affect the time domain and frequency domain at the same time. In this paper, the voice of radiotelephony communication in the three fatigue states is converted into speech spectrum images that can reflect the characteristics of both the time domain and frequency domain, and the grayscale co-existence matrix (GLCM) is used to extract the typical feature parameters in four dimensions, compare the changes of the characteristic parameters of the controllers in different states, and confirm that the selected features have a good discrimination. The selected features were detected as the input features of the controller fatigue detection model, and the detection accuracy of using the spectral pattern features combined with the traditional features as the input features was the highest, reaching 95.49%, which was 4% higher than that of the traditional features alone. The results show that the change of controllers fatigue state will be intuitively reflected on the spectrogram and will have an impact on its eigenvalues, and good results can be obtained by using this influence to detect the controllers fatigue state.
    2024,15(2):56-65. DOI: 10.16615/j.cnki.1674-8190.2024.02.07
    Abstract:
    Xinjiang is an important area linking China with Central Asia and Europe, and is a vital land pivot point of China"s "One Belt, One Road". As the number of flights increases year by year, the control pressure in Xinjiang control area increases year by year, and the problems of uneven load distribution and increasing conflict points in the sector are becoming more and more serious. This paper forecasts the traffic growth of the Xinjiang control region in 2035 in the light of the development requirements of China"s "One Belt, One Road" and "Air Silk Road", and then conducts a capacity assessment of the current sector classification scheme based on the controllers" workload. Finally, computer simulation technology is used to evaluate the sector designation scheme in 2035. The simulation results show that the new sector division can effectively reduce peak day traffic and peak hour traffic. Through reasonable division of sectors with high controller load, the control pressure has also been significantly alleviated. The simulation verifies the rationality and effectiveness of sector division.
    2024,15(2):66-76. DOI: 10.16615/j.cnki.1674-8190.2024.02.08
    Abstract:
    In recent years, with the rapid development of civil aviation transportation, the research of aircraft maintenance routing has been paid more and more attention. In order to explore the research status, hot spots and frontier trends of the aircraft maintenance routing problem, this paper takes the domestic and foreign literatures on aircraft maintenance routing collected in the core databases of China National Knowledge Network (CNKI) and Web of Science from 2000 to 2022 as the analysis data. The CiteSpace V software is used as a auxiliary research tool to analyze the scholars, institutions and cooperative relationships in the field of aircraft maintenance routing. Combining the knowledge maps and literature content, the hot spots and frontiers of research in this field are summarized. Considering the domestic aircraft maintenance routing research, research suggestions are put forward for the research trend and focused research content in this field in China, and provide reference for future aircraft maintenance routing research scholars.
    2024,15(2):77-89. DOI: 10.16615/j.cnki.1674-8190.2024.02.09
    Abstract:
    Least risk bomb location structure is a device for placing suspicious explosives on the aircraft. Exploring the influence of structure size and explosive location on its anti-explosion performance can provide a reference for improving the design. Based on the method of combining orthogonal experimental design with numerical simulation, the maximum strain and deformation of each dangerous part of LRBL structure are used as evaluation indicators. The range analysis method and variance analysis method are respectively used to carry out parameter sensitivity analysis on the five influencing factors of the tank wall thickness, bottom cover thickness, connection boss thickness, shear pin diameter and explosive position of LRBL structure. The results show that when the explosive equivalent was determined as 200g, the significant degree of influence of each factor on the antiknock performance of the LRBL structure from large to small was as follows: explosive position, tank wall thickness, bottom cover thickness, boss thickness and shear pin diameter; Based on comprehensive analysis of evaluation indicators, the LRBL structural design scheme at the optimal level of each factor is obtained. The research results have guiding significance and reference value for the application of LRBL structure in engineering practice.
    2024,15(2):90-100. DOI: 10.16615/j.cnki.1674-8190.2024.02.10
    Abstract:
    As a necessary test of aircraft development,the ground vibration test of full-size aircraft has the characteristics of multiple coordination units, complex system, long implementation time and high risk. Facing the need of efficient development of advance aircraft, it is necessary to improve the capability of the test, by introducing the digital means. In this paper, the flow of ground vibration test in traditional mode has been summarized, the elements of digital experiment has been analyzed and the digital test programme has been constructed preliminarily. Based on the application of ground vibration test on rocket, the significant benefits in reducing test risks and improving test efficiency of this mode are shown, and it is necessary to promote the development of digital real fusion simulation and application platform, to promote the implementation of this technology.
    2024,15(2):101-107. DOI: 10.16615/j.cnki.1674-8190.2024.02.11
    Abstract:
    The Environmental Qualification Test of civil aircraft airborne equipment is to demonstrate that the equipment meets the applicable environmental standards, and further meets the Technical Standards Order applicable to it, which is of great significance to the airworthiness certification of airborne equipment. At present, the Environmental Qualification Test of civil aircraft airborne equipment in domestic is still in the continuous improvement stage. This paper takes the environmental qualification test of certain airborne equipment as an example, introduces a set of workflow for the Environmental Qualification Test, including three stages: Environmental Qualification Test plan development, environmental test procedure development, and qualification testing. Then combined with the Minimum Operational Performance Standard (MOPS) applicable to the equipment and the DO-160 standard (Environmental Conditions and Test Procedures for Airborne Equipment), it describes in detail about the work content and focus of each stage in the workflow, as well as the planning of airworthiness liaison and suggestions. This equipment has got the TSO approval, indicating that this workflow can be effectively applied to the Environmental Qualification Test of airborne equipment and support for the airworthiness certification, and can also provide reference for the Environmental Qualification Test of subsequent airborne equipment.
    2024,15(2):108-116. DOI: 10.16615/j.cnki.1674-8190.2024.02.12
    Abstract:
    The aircraft AC power generation system is the key subsystem of the power supply system and the main source of power for the whole aircraft, so a complete safety analysis is required. Methods such as fault tree analysis, failure mode and effect analysis are used for traditionally safety analysis, and less attention is paid to safety issues caused by nonlinear interactions between system components. The article introduces the basic structure of the AC power generation system of a typical large passenger aircraft, using the method of combining system theory process analysis and the theory of timed automata formal analysis, build the safety control structure diagram of the AC power conversion process, identify Unsafe Control Action (UCA), and generate relevant causal scenarios by integrating Failure Mode and Effect Analysis(FMEA), combined with formal tools based on the theory of timed automata for system modeling and UCA verification. The comparison with the accident investigation results of typical power system shows that the method used can effectively identify the cause of the accident and conduct a comprehensive analysis, which can be used as an effective supplement to the traditional safety analysis method of aircraft power system.
    2024,15(2):117-124. DOI: 10.16615/j.cnki.1674-8190.2024.02.13
    Abstract:
    Experiment and numerical simulations were carried out to study the performance of bird strike with blades of an engine primary compressor. Firstly, the bird impact test, in which the bird weight, velocity and rotate speed of engine blades were 1000g, 195m/s, 8525 r/min respectively, was made in a vacuum space. Then the full scale finite element calculation model of bird striking on blades of an engine primary compressor was established, and the numerical simulation results are extremely identical with the test results with acceptable error to show the reliability of simulations. Also, the ability of engine blades against bird strike in different situations was researched. The results indicated that big bird impact leads to a worse situation compared with medium birds flock and small bird lock. Large deformation appears at the tip of the blades due to the impact at the tip part, while impact at the root and middle of the blades will cause a large concentrated stress around the root of blades. The research methods and our conclusions in the current paper are significant to the design of engine blades against to the bird impact.
    2024,15(2):125-133. DOI: 10.16615/j.cnki.1674-8190.2024.02.14
    Abstract:
    The bird-swallowing ability of engine must meet the requirements of the national military standard and airworthiness. It is necessary to propose a reliable method to assess the bird-swallowing ability of the engine before bird-swallowing tests, the test risk can be reduced and the test success rate can be increased. Based on the bird-swallowing capability simulation and verification project of a turbofan, this paper proposes a method for evaluating the bird-swallowing capability of an engine based on simulation analysis, momentum analogy and contact stress analogy. According to the relevant standards and specifications, the test requirements were determined, and the bird-swallowing test was carried out and verified.The test results and assessment methods can provide reference for the development of other turbofan models.
    2024,15(2):134-141. DOI: 10.16615/j.cnki.1674-8190.2024.02.15
    Abstract:
    Aeronautical electronic equipment is used for data collection during flight, usually fixed to the nose radome using mounting brackets, studying the stiffness and first-order frequency performance of the mounting brackets to avoid plastic deformation and resonance during flight, which is of great engineering significance for improving flight stability. The static strength and modal analysis of the mounting bracket under inertial load show that the bracket has good Bending stiffness, but the first order frequency is low. Using a sensitivity analysis method to determine the design variables of the installation bracket, with the goal of minimizing the total weight of the structure as the optimization objective, the thickness of each component of the bracket is optimized while ensuring the stiffness and first-order modal performance of the installation bracket. Vibration tests are conducted on the optimized installation bracket structure, and the test frequency values and finite element calculation values are in good agreement, verifying the accuracy of the finite element modal analysis method. The results show that the stiffness of the optimized installation bracket structure remains basically unchanged, with an increase of 18.09% in first-order frequency and a weight reduction of 19.33%. The improved design meets the equipment installation requirements.
    2024,15(2):142-151. DOI: 10.16615/j.cnki.1674-8190.2024.02.16
    Abstract:
    As an important new part of Airborne Integrated Surveillance System (ISS), Automatic Dependent Surveillance-Broadcast (ADS-B) system shows advantages in surveillance and efficiency under the premise of ensuring flight safety, leading the development of future surveillance technology. By analyzing the development process of airborne ADS-B products and technologies at home and abroad. Then, from the perspective of ensuring flight safety and efficiency, key technologies of ADS-B system are analyzed and summarized. Finally, the development trend of the technology is discussed and prospected by the concept of next generation airspace operation, and 4 future development directions of ADS-B technology are proposed, which provide the development direction for the development of ADS-B technology of airborne ISS. This will promote the development of ADS-B technology in practical operation and theoretical research.
    2024,15(2):152-165. DOI: 10.16615/j.cnki.1674-8190.2024.02.17
    Abstract:
    As the complexity of modern aircraft systems continues to grow, traditional development methods are be-coming increasingly challenging in terms of management and maintenance. Model-Based Systems Engineer-ing (MBSE) provides a comprehensive and integrated approach to systems engineering, enhancing communi-cation, collaboration, and traceability throughout the development process. We first evaluate the development process of aviation flight control systems in current systems engineering practices, elucidating the drawbacks of traditional development approaches and the core principles and advantages of MBSE, as well as common-ly used tools and methods in its implementation. We then demonstrate how MBSE uses models to support the specification, design, analysis, verification, and validation of complex systems during the development of flight control systems. Finally, we outline future research directions, including the development of advanced MBSE tools and methods, the prospects for combining MBSE with agile development, and the need for im-proved interoperability and standardization in MBSE practice. This paper provides resources and insights for aviation industry professionals, systems engineers, and researchers interested in leveraging MBSE methodol-ogies and tools to improve the design, development, and performance of flight control systems.
    2024,15(2):166-172. DOI: 10.16615/j.cnki.1674-8190.2024.02.18
    Abstract:
    It is well known that there are several vertical flight phases for the aircraft in the flight. The cruise flight phase takes most of the flight time, flight distance and fuel consumption, so it is important and necessary to develop the FMS vertical trajectory prediction algorithm for the cruise flight phase, aiming to improve the economy, comfort and safety of the flight. In order to meet the versatility of the vertical trajectory prediction algorithm between different types of aircraft in the cruise phase and improve the accuracy and reliability of the prediction, the algorithm of vertical trajectory prediction for cruise flight phase is proposed in this paper. By calculating the cruise speed profile and constructing the realistic atmospheric model of prediction, and then calculating the cruise fuel flow data based on the aircraft model of first-principles, the vertical trajectory prediction for the cruise phase is given by designing the vertical trajectory prediction algorithm logic. Finally, the effectiveness and accuracy of the algorithm are verified by ground simulation and air flight test. The results show that the vertical trajectory prediction algorithm of FMS cruise phase based on the aircraft model of first-principles can predict the cruise trajectory of the aircraft, and the prediction accuracy error is less than 1%.
    2024,15(2):173-178. DOI: 10.16615/j.cnki.1674-8190.2024.02.19
    Abstract:
    The data fusion of radar and ADS-B is an effective method to surveille the ‘black flights’ and flying birds. However, the tracking performance of the two sensors has large differences and is easy to fluctuate, which will bring a decline in fusion accuracy. This paper proposes a data fusion method of radar and ADS-B based on track quality assessment. Firstly, the effects of local track accuracy, data update times and sensor measurement errors on local track quality are analyzed and quantified into corresponding assessment factors. Secondly, these assessment factors are combined to calculate the quality weighting factors of the local track. Finally, the asynchronous track fusion processing of radar and ADS-B is completed based on the distributed fusion structure. The results of simulation experiments show that the fusion processing method proposed in this paper can effectively improve the fusion accuracy, and the tracking errors are better than the traditional algorithms when the sensor tracking performance fluctuates. The fusion effect of engineering application also verifies that the proposed method is helpful for the integrated surveillance of low-altitude cooperative and non-cooperative targets.
    2024,15(2):179-187. DOI: 10.16615/j.cnki.1674-8190.2024.02.20
    Abstract:
    Due to the advantages of low cost and no casualties in unmanned aerial vehicle (UAV) autonomous air combat, it has attracted increasing attention. This paper is based on the deep deterministic policy gradient (DDPG) reinforcement learning method. Building upon the situation evaluation function as the reward function for reinforcement learning, a comprehensive reinforcement learning environment is designed that considers flight altitude limits, flight overload, and flight speed limits. The interaction between the DDPG algorithm and the learning environment is achieved through the fully connected carrier speed control network and the environment reward network. The end condition for air combat is designed based on abnormal height and speed, missile lock time, and combat time. By simulating one-on-one air combat, the effectiveness of this combat control method is validated in terms of learning under environmental constraints, situation evaluation scores, and combat mode learning. This research can provide guidance for the further development of autonomous air combat.
    2024,15(2):188-194. DOI: 10.16615/j.cnki.1674-8190.2024.02.21
    Abstract:
    (小5号黑正):As the demand for intelligent application in airborne embedded computing system is increasing, the convolution neural network model with excellent performance can effectively solve the problems of target recognition and edge detection in air combat scenes. However, the huge weight parameters and complex network layer structure of convolutional neural network make its computational complexity too high, and the required computing resources and storage resources also increase rapidly with the increase of network layers, so it is difficult to deploy in airborne embedded computing systems with strict requirements on resources and power consumption, which restricts the development of airborne embedded computing systems towards high intelligence. Aiming at the demand of ultra-lightweight intelligent computing in the resource-constrained airborne embedded computing system, a set of optimization and acceleration strategy of convolutional neural network model is proposed. After ultra-lightweight processing of the algorithm model, a convolutional neural network accelerator is built by combining acceleration operators, and the function verification of network model reasoning process is carried out based on FPGA. The experimental results show that the designed accelerator can significantly reduce the occupancy rate of hardware resources and obtain a good algorithm speedup ratio, which has important technical significance for the design of airborne embedded intelligent computing system.
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    Available online:May 17, 2024, DOI:
    Abstract:
    In aerospace engineering, it is important to study the influence of wet and thermal environment on the interlayer fracture toughness of resin matrix composites. In this paper, the microstructure of type I and type II interlayer fracture toughness experiments under different wet and thermal conditions were analyzed, and the effect of wet and thermal environment on the interlayer fracture toughness of resin matrix composites was obtained. The research results indicate that the humid and hot environment has a completely opposite effect on the interlayer fracture toughness of type I and type II resin composite materials. As the temperature increases, the interlayer fracture toughness of type I resin composite laminates shows an upward trend, while the interlayer fracture toughness of type II resin composite laminates shows a downward trend. During Type I delamination, a large number of fiber bridging phenomena occur. In humid and hot environments, the resin softens and fiber bridging phenomena increase, leading to an increase in Type I interlayer fracture toughness with increasing temperature; In a humid and hot environment, as the temperature increases, the shear strength of the resin gradually decreases, and the interfacial shear strength between the resin and fibers also gradually decreases, resulting in a decrease in type II interlayer fracture toughness with increasing temperature.
    Available online:May 17, 2024, DOI:
    Abstract:
    The structural characteristics, manufacturing requirements and interface accuracy requirements of helicopter composite duct are analyzed. According to the structural characteristics and requirements, a new manufacturing technology of helicopter composite duct is proposed, which includes precision manufacturing technology of parts, adhesive assembly technology of duct structure and finishing technology. The technology is discussed and its application is reported. Compared with the traditional dolphin helicopter duct manufacturing technology in many aspects, the new helicopter composite duct manufacturing technology has achieved the effects of reducing cost, shortening manufacturing cycle, simplifying tooling, improving quality and ensuring interface accuracy, which has important reference value for the precision manufacturing of other helicopter parts.
    Available online:May 17, 2024, DOI:
    Abstract:
    To reduce the probability of helicopters being discovered during mission execution, based on the geometric optics method and consistent diffraction theory, the effects of different tail rotor airfoil thickness, curvature, and scissor angle of tail rotor on RCS were studied for the helicopter tail rotor. Using radar to irradiate the tail rotor from the ground and radar to irradiate the tail rotor from the rear of the helicopter, the RCS of the tail rotor is analyzed using two different irradiation radar orientations. By comparing the RCS peak and mean values of different parameters of the tail rotor, the more favorable conditions for the stealth of the helicopter tail rotor are determined. When illuminating the tail rotor from the ground, the RCS with small thickness and curvature of the tail rotor will be smaller, and changes in the angle of the scissors will cause changes in the peak phase of the RCS. When the radar illuminates the tail rotor from the rear, the RCS of the tail rotor with smaller thickness is smaller, while the RCS peak of the tail rotor with larger curvature is smaller. Based on comprehensive analysis, the smaller the thickness and curvature of the tail rotor, the more favorable it is to reduce the RCS of the helicopter tail rotor.
    Available online:May 08, 2024, DOI:
    Abstract:
    The supersonic variable Mach number wind tunnel can operate at multiple Mach numbers during a single operation, which has unique advantages for studying supersonic maneuvering process and scramjet Ramjet starting. The supersonic variable Mach number nozzle is the core component for adjusting Mach number during wind tunnel operation, and its design quality directly determines the flow field quality of the experimental section. This article reviews the research progress of nozzle design in supersonic variable Mach number wind tunnels both domestically and internationally in recent years, and introduces four typical variable Mach number wind tunnel nozzle schemes (flexible wall, semi-flexible wall, profile rotation, asymmetric), as well as their numerical simulation and experimental calibration results; Summarized the key considerations in the design of different variable Mach number nozzle schemes, and provided prospects for the next research direction.
    Available online:May 08, 2024, DOI:
    Abstract:
    To clarify the effect of breakaway groove on the breakaway load of emergency fuse-pin for civil main landing gear, a series of FEM simulations were conducted to study the influence of structural changes of breakaway groove on the breakaway load for outer-groove, long outer-groove, inner-groove and short inner-groove emergency fuse-pin. The breakaway load and failure mode were comparison?analyzed between inner-groove and inner-groove emergency fuse-pin by experimental tests. The results reveal that the breakaway failure of fuse-pin is extended from inside to outside. The breakaway loads increase with increasing the sectional area and exhibit a linear relationship. The breakaway load variation with the sectional area(shear strength coefficient) of through-hole pin is the maximum, followed by outer-groove pin, and the inner-groove pin is the minimum. Compared with other pins, the breakaway load of inner-groove pin is easy to control and less affected by sectional area and overall size. The fracture morphology is changed from ductile fracture of outer-groove pin to brittle fracture of inner -groove pin. Accordingly, the design of inner-groove pin meets the aviation regulations requirement for civil main landing gear.
    Available online:May 08, 2024, DOI:
    Abstract:
    The cargo compartments of most current aircraft types are equipped with ventilation function. It is of great significance for flight safety to explore the influence of ventilation effect on smoke diffusion in the cargo compartment and determine the layout of smoke detectors in the cargo compartment under ventilation conditions. A numerical model of fire smoke in DC-10 aircraft cargo compartment is established by using computational fluid dynamics method, and the flow field characteristics of fire smoke are analyzed by simulation. POD flow field orthogonal decomposition theory was used to reveal the influence mechanism of ventilation on fire smoke flow field, the layout of smoke detector in smoke cargo compartment under ventilation condition is studied by simulation and experiment. The results show that ventilation can inhibit the upward diffusion of fire smoke and delay the time for smoke to reach the cargo compartment ceiling. With the increase of ventilation volume, the energy proportion of small and medium-sized disordered flow modes in flow field increased, while the energy proportion of large-scale flow modes of smoke moving close to the cargo ceiling decreased, which resulted in a longer time for smoke to reach the ceiling. By comparing the response performance of the three different detector layouts experimentally, it is concluded that the optimal detector layout is to install the detector near the corner of the cargo hold and away from the vent.
    Available online:May 08, 2024, DOI:
    Abstract:
    The compatibility of aircraft landing gear and pavement is of great significance to the ground motion ability of aircraft. This paper calculates the landing gear load and tire load distribution under different working conditions for a large aircraft. The Portland Cement Association method based on Westgard laminate theory and the United States Army Corps of Engineers method based on California bearing ratio are used to calculate. The influence of the landing conditions, ground mobility, tire number, tire deflation and track widths on the aircraft classification number(ACN) is analyzed. The aircraft floatability under rigid and flexible pavement is analyzed. The increased tire load and uneven load distribution caused by vertical overload and tire deflation can weaken the floatability of aircraft to varying degrees, especially during turning and landing conditions with tail sinking. Therefore, they need to be limited. Increasing the number of tires and the distance between them can improve the floatability, but the structural design, strength margin and other factors should also be taken into consideration to optimize the design of trolley type landing gear.
    Available online:May 08, 2024, DOI:
    Abstract:
    In order to ensure the high surface quality and high dimension precision of the helicopter landing gear wheel shaft after spraying tungsten carbide coating. In this paper, the research on tungsten carbide coating grinding technology for wheel shat is carried out from three aspects of grinding strategy, clamping tool and grinding strategy. First, we used the orthogonal experimental method to find out the grinding parameters that could make the surface roughness of the parts reach Ra0.4; Then, the problems of ellipse and taper in the process of outer circle grinding are eliminated by improving the fixture, adjusting the way of grinding wheel feed and improving the grinding strategy; Finally, the outer circle dimensions of 15axles were collected and calculated, and the process capability index was not less than 1.33. The feasibility and stability of the whole grinding process are proved.
    Available online:May 08, 2024, DOI:
    Abstract:
    Flight control system is typical safety critical system, and the reliability of flight control system plays an important role in ensuring the safe operation of aircraft. Traditional reliability analysis methods have a heavy reliance on the experience of analysts, which makes it easy for inconsistencies between reliability models and design models. The fault propagation behavior of the system is thoroughly described by the Architecture Analysis Design Language (AADL) and stochastic Petri nets (SPN), and a method for model-based reliability analysis is proposed. The nominal model and error model of a lateral fly-by-wire flight control system were constructed using AADL. A method for extracting error propagation information from the AADL model was proposed, and the SPN model described the fault propagation behavior of the system was automatically generated by extracting the information of AADL model. Based on the SPN model, Monte Carlo simulation was used to evaluate the reliability of the lateral fly-by-wire flight control system, compared with the fault tree analysis method, the error is less than 0.018%, which can be neglected in practice. Through the method of this study, the reliability model is automatically generated by the AADL model, which ensures the consistency between the reliability model and the design model and avoids reliance on the experience of designers.
    Available online:May 02, 2024, DOI:
    Abstract:
    Sensor aircraft and integrated wings embody the integrated design concept of integrating functional components and structures. However, there are problems with discontinuous skin force transmission and difficult connection in the wing structure, making the connection strength of functional skin a control factor in the design process. Therefore, this article combines the functional requirements and structural characteristics of the integrated wing, adopts a simplified connection calculation method, conducts force transfer analysis and connection characteristics analysis on the key sections at the separation surface of the functional skin design, obtains the ideal connection load and connection parameters at the separation surface, completes the connection design and size design, and verifies it through finite element analysis and optimization analysis. The results show that the estimated bending moment distribution of the box section using this force transfer analysis method is consistent with the finite element analysis results; The calculated size distribution of each section of the box section structure is similar to the optimization results, which can meet the requirements of connection strength and stability; The larger the effective height of the wing beam in the box section structure, the greater the load it bears, and the more consistent the optimization results with the force transfer analysis results.
    Available online:May 02, 2024, DOI:
    Abstract:
    The high-performance attitude controller can effectively suppress comprehensive effects caused by uncertainties and external dynamic disturbances, and ensure that the quadrotor can safely and reliably fly to complete the designated mission. Therefore, nonlinear uncertainties of quadrotor flight systems are approximated by a radial function neural network (RBFNN) quadrotor, and an extended state observer is designed to estimate lumped disturbances caused by RBFNN approximation errors and external disturbances in this paper. The black box problem of RBFNN is solved by using a model identification error and a tracking error as decision variables. Then, an adaptive robust anti-disturbance attitude tracking controller is designed for quadrotor flight systems based on dynamic surface control and Lyapunov stability theory, and an auxiliary system is constructed to suppress the effect of filtering error on the closed-loop system performance. Finally, Simulation results show that the quadrotor can precisely track the desired attitude angles, and the proposed controller has strong robustness and stability in the presence of uncertainties and disturbances.
    Available online:May 02, 2024, DOI:
    Abstract:
    In recent years, scholars have conducted extensive research on air precoolers, which are used for pre-cooled combined cycle engines for hypersonic aircraft. These precoolers are generally composed of multiple sets of micro-tube bundles, but they have problems such as large flow-induced vibration and high processing requirements. Therefore, it is necessary to redesign the heat exchange core of the precooler and carry out further research on flow heat exchange. This article analyzes the demand for modification based on biomimetic fractals, sorts out the application of honeycomb-like fractals, tree-like fractals, and mixed structures on biological surfaces, which enhance heat exchange in new pre-cooling cores. Additionally, biomimetic concave-convex surface structures and hydrophobic structures are applied to reduce surface flow resistance and suppress frosting. At the same time, three design examples of “cylindrical” biomimetic pre-cooling heat exchange cores are given, which can be applied to the aerospace field. Finally, the article looks forward to the development prospects of combining biomimetic microchannel heat exchange structures with precooler heat exchange core design.
    Available online:May 02, 2024, DOI:
    Abstract:
    The aircraft power supply system is the power source of all electrical equipment on board, thus its safety and reliability are pretty important. Against the backdrop of environmental protection and high-efficiency development needs, research and application of more/all electric aircraft technology with electric power as the core is advanced. The widespread use of electric drive devices and power electronic devices has led to the complexity of aircraft power supply system structure, which puts forward higher requirements for aircraft reliability, safety, testability and maintainability, so that researches on fault diagnosis technology for aircraft power supply systems are of great significance. This paper firstly introduced the composition structure and respective functions of aircraft power supply system. Secondly, the development process of aircraft power supply system was outlined. Thirdly, the characteristics of typical domestic and foreign power supply systems were compared. Fourthly, the main failure modes, fault characteristics and failure causes of aircraft power supply system were summarized, and a design architecture of aircraft power health management system was proposed. Fifthly, the research progress of fault diagnosis methods based on model and data were reviewed, then, the characteristics of various diagnostic methods were evaluated from aspects such as accuracy, data demand, applicability and implementation difficulty. Finally, this paper gave the challenges and development trends of fault diagnosis technology for aircraft power supply system.
    Available online:May 02, 2024, DOI:
    Abstract:
    In order to evaluate the propulsive efficiency of turbofan, turboprop and prop-fan engines, a mathematical model for propulsive efficiency analysis was established by using energy-momentum method based on the model of separate exhaust turbofan engines, and a unified propulsive efficiency analysis method was formed for turbofan, turbofan and propeller fan engines. Different external fan pressure ratio, equivalent bypass ratios and different flight Mach number are selected for calculation. The calculation results show that the propulsion efficiency of turboprop engine is higher at medium to low flight Mach number, the propulsion efficiency of prop-fan engine is higher at medium to high flight Mach number, and the propulsion efficiency of turbofan engine is higher at high subsonic flight Mach number. The results confirm the existing flight Mach number interval distribution law of the superior propulsion efficiency of turboprop, prop-fan and turbofan engines, and provide a method for the research and analysis of the propulsion efficiency of turbofan, turboprop and prop-fan engines.
    Available online:May 02, 2024, DOI:
    Abstract:
    The stability of compressor operation has an inducing and amplifying effect on the stability and performance of the entire engine. Therefore, it is required that the wider the flow margin of the compressor, the better, to adapt to the working stability of the engine under variable operating conditions. This paper attempts to propose a new blade structure with micro pits distributed on the suction surface of the mainstream blade by referring to the "golf ball effect". The flow of a certain type of centrifugal compressor impeller is numerically simulated by using the CFX fluid dynamics software to study the effect of adding micro pits on the performance of flow separation structure and flow margin at different parts of the suction surface of the blade. Study the effect of adding micro pit structures with radii of 0.25-0.3mm at different parts of the blade suction surface on structural performance and flow margin. The research results indicate that adding micro pits at the leading and trailing edges of the mainstream blade suction surface can improve the flow margin. When the radius of the micro pits is 0.3mm, the flow margin effect is the best, increasing by 3.01% and 3.15%, respectively. The use of new structural blades reduces smaller peak efficiency and increases compressor flow margin, providing a reference for the design of centrifugal compressor impellers.
    Available online:May 02, 2024, DOI:
    Abstract:
    The long landing distance from 50 ft to touchdown is an over-limit event frequently occurring during the landing phase and also significantly increase the risk of landing accidents. The study on the impacts of geographical environmental factors of the over-limit event can provide references for airport site selection and flight quality evaluation. Based on the flight QAR (Quick Access Record) data, topographic data and climate data of the airports, global and local correlation analysis were adopted to identify the main factors influencing the over-limit event. The regression model between the event frequency and elevation, fluctuation, air temperature was established, based on the geographical weighted regression model. According to the regression coefficients, the impact modes of these factors were divided into five categories using K-means method, so as to explore the spatial pattern and mechanism of geographical environmental factors on the over-limit event. The results show that elevation, fluctuation, air pressure and air temperature have a significant impact on the frequency of the "long landing distance" over-limit event. There is an obvious spatial differentiation of the impact of geographical environment factors. The spatial distribution of airports under the same impact mode shows clustering.
    Available online:April 01, 2024, DOI:
    Abstract:
    The classic sled-type landing gear makes it challenging to take off and land in challenging terrain, with the widespread usage of rotorcraft UAVs in both civil and military domains. This research develops a two-stage buffered adaptive landing gear that is similar to a human leg in order to increase the landing area and application range of rotorcraft UAVs. An adaptive landing gear attitude adjustment strategy was proposed after researching the positive and negative kinematics of the bionic leg. A bionic quadruped hexacopter UAV landing dynamics model was established, landing dynamics simulation was carried out using the multi-body dynamics software simcenter 3D, and a comparison of landing performance with the conventional sled landing gear was carried out. The research demonstrates that the two-stage cushioned adaptive landing gear in the landing leg style and its attitude adjustment strategy can reduce roll angle by 95.69% and overload coefficient by 34.06%, proving that the two-stage cushion adaptive landing gear has excellent shock absorption and cushioning capability in the face of complex terrain.
    Available online:April 01, 2024, DOI:
    Abstract:
    This paper uses the theory of failure physics and reliability simulation analysis method to analyze the reliability of electronic controller. By establishing a digital prototype model of electronic controller, the corresponding stress analysis and fault prediction are conducted to evaluate the average time to first failure (MTTFF) reliability index of the electronic controller, and optimize the design based on the weak links found in simulation results. It is indicated that the difference between the reliability results and the theoretical calculation results are not significant, and can be used as a basis for evaluating the reliability indicators of models, reducing the cycle and cost of using physical prototypes for reliability testing; At the same time, the optimization and improvement have significantly improved the reliability design of the electronic controller, laying a theoretical foundation for subsequent model reliability evaluation and design.
    Available online:February 25, 2024, DOI:
    Abstract:
    The integral inertial particle separator is a helicopter air inlet protection device. It has excellent performance and wide application compared with other protection devices, which is of great significance to ensure the regular operation and improve the service life of helicopter engines. This paper summarizes the research progress of integral inertial particle separators, including the following aspects: 1) The classification and aerodynamic parameters of the integral inertial particle separators are introduced. 2)The research methods and their results of the integral inertial particle separators are sorted out. 3)The factors affecting the performance of the integral inertial particle separators are summarized and analyzed. 4)The future development of integral inertial particle separators is predicted. This paper can be the reference for future study and the guide to integral inertial particle separators’ optimization design.
    Available online:February 25, 2024, DOI:
    Abstract:
    The landing-gear retracting and releasing system and braking system of UAV plays a crucial role in the process of takeoff, landing, and braking of UAVs. Electrostatic hydraulic systems not only retain the advantages of traditional hydraulic systems, but also have the advantages of electric actuation. According to the working principle of the electro-hydrostatic actuator, an electro-hydrostatic system integrating the landing-gear retracting and releasing and braking functions of unmanned aerial vehicles is designed. The improved PID control method is applied to the landing-gear retracting and releasing function, and two fuzzy PID control methods are designed to apply to the anti-skid braking function. On this basis, a co-simulation based on AMESim and MATLAB/Simulink is conducted to verify the system performance, Finally, the simulation results are compared and analyzed. The results show that the designed control method can normally complete the landing-gear retracting and releasing and braking of unmanned aerial vehicles, and the control effect is good.
    Available online:February 25, 2024, DOI:
    Abstract:
    The configuration management of civil aircraft brake control system plays a key role in the process of system design and development and airworthiness compliance verification. In order to improve the configuration management capability of civil aircraft brake system, the software designed and developed can meet the airworthiness requirements, this paper introduces the concept and method of brake system control software configuration management, and illustrates how to combine configuration management with software design by means of system thinking and information flow to carry out whole-life-cycle configuration management. By combining with the requirements of DO-178C, configuration data digital management mechanism based on product configuration is established, unique data source of brake control system development is created. The result shows that a unified configuration database is established with configuration baseline management combination in which the information and status are accurately recorded strictly to ensure the real-time, traceability, integrity and effectiveness of status information, and achieve the final configuration control goal to meet the airworthiness requirements.
    Available online:February 25, 2024, DOI:
    Abstract:
    A quality risk identification and assessment method for aircraft manufacturing and maintenance based on FMEA is applied to analyze the potential failure modes and their causes of aircraft in manufacturing and maintenance, evaluate these failure modes, and formulate recommended measures for important failure modes to reduce or avoid the occurrence of failures. This paper presents a set of mapping rules for the application of DFMEA analysis results in risk identification and assessment of manufacturing and maintenance quality. The analysis scope is extended from the design end to the use and maintenance of aircraft. Through the combination of the above methods and measures, the technology realizes the analysis and evaluation of the potential failure mode, failure cause, Severity, recommended measure effect, measure coverage and repeatability in the manufacturing and maintenance process starting from the design stage, which can more scientifically and comprehensively analyze, evaluate and deal with the quality risk of aircraft manufacturing and maintenance.
    Available online:February 25, 2024, DOI:
    Abstract:
    Practice has shown that big data technology can empower the management process. As an important project in the complex high-end program of commercial aircraft development, the commercial aircraft MOC9 test project will generate a large amount of project management data during development. Therefore, it is necessary to study how to use big data technology to promote such projects to achieve project objectives. Based on the characteristics of the MOC9 test project under the commercial aircraft development program and its demand for big data management, this article conducts study on the MOC9 test project from multiple aspects such as architecture planning, data acquisition and storage, data cleaning and processing, analysis mining, and visual display, combined with big data technology processing processes and methods. The study results show that establishing a quantitative visual model for MOC9 projects through big data technology is very helpful for project managers to master the overall situation of the project, locate the root causes of problems, and identify potential risks of the project.
    Available online:February 15, 2024, DOI:
    Abstract:
    Morphing aircraft can change its aerodynamic configurations to obtain optimized aerodynamic performance. Smart material actuator and flexible skin are the key technologies of morphing aircraft. The research of actuators made of shape memory alloys, piezoelectric materials and magnetostrictive materials is introduced. The development of flexible skin based on material elasticity and structure design is analyzed. The related research issue and interests are summarized and prospected.
    Available online:February 15, 2024, DOI:
    Abstract:
    The methods of waypoint setting and point curve fitting which are not complex was usually adopted in the path planning of UAV, and the expected heading angle is given in segments. The expected heading does not automatically modified with changes in the route. The ability to automatically and quickly generate the expected heading and position is lacking. In order to solve the ability, a vector field algorithm suitable for complex flight mission path planning is studied, and a simulation verification system to verify the effectiveness of its algorithm is developed in this paper. The concept of vector field is introduced in order to design a heading angle guidance law. An aircraft at any position can smoothly fly to the desired target path along the desired heading angle, and then complete the flight task along the desired target path. The implicit function equation is used to establish the desired path vector field, and the principle and method of path planning based on vector field are geometrically analyzed. According to the Lyapunov stability theory, the boundedness of the planned path error is proved. The distance error and the heading angle error can be stably converged to 0 with the help of the heading guidance law. Taking the path planning of the altitude hold mission for a quad tiltrotor UAV as an example, the desired path of smooth flight is planned using the vector field method and the piecewise transition strategy. The verification is conducted and some simulation results are given, which show that the vector field path planning algorithm is feasible and effective for the mission flight planning of an aircraft.
    Available online:February 15, 2024, DOI:
    Abstract:
    Fault prediction technology has important application value in ensuring the reliable operation of instrument landing system and improving ATC effectiveness. Combining the operation characteristics of instrument landing system and actual operation and maintenance work, a fault prediction method of instrument landing system based on GRU is proposed. Taking heading beacons as the research object, the monitoring parameters are used as fault characteristic parameters after analyzing the relationship between their monitoring parameters and equipment operation status. Then, the GRU algorithm is used to predict the future change trend of the monitoring parameters according to their time step and significant time-varying characteristics. Finally, the probability of "failure" is calculated according to the subordinate function of the monitoring parameters, and the prediction of heading beacon failure is realized. The relative prediction accuracy of the GRU prediction model is over 95% after two years of training with the monitoring parameter data. By comparing the prediction of heading beacon failure data and normal operation data, the validity of the monitoring parameters as failure characteristics to characterize the operation of the heading beacon and the effectiveness of the GRU-based failure prediction method are verified.
    Available online:February 15, 2024, DOI:
    Abstract:
    In order to effectively evaluate the maritime emergency rescue capability of helicopters and improve their emergency rescue efficiency, it is proposed that the safety issues in the three stages of "pre-prevention--in-event response--post-event recovery" in the rescue process be taken into account in the helicopter maritime emergency rescue system.Based on the "5W1H" analysis method, the research framework was designed, and the evaluation indicators of helicopter maritime emergency rescue capability were screened through literature analysis, questionnaire survey, expert consultation and other methods, and 21 evaluation indicators were determined to build the evaluation index system of helicopter maritime emergency rescue capability. The analytic hierarchy method based on D-S evidence theory was used to determine the index weight, and the fuzzy comprehensive evaluation method was used to construct a comprehensive evaluation model of helicopter maritime emergency rescue capability. The evaluation model was applied to the rescue exercise taking the injury of offshore wind turbine maintenance personnel as an example, and the score was 86.89, and the rescue ability was judged to be "strong".The results show that the evaluation index system and evaluation model have certain practicality, and can effectively evaluate the ability of helicopter emergency rescue at sea.
    Available online:January 19, 2024, DOI:
    Abstract:
    With the widespread application of ceramic matrix composites in hot end components of advanced aero-engines, it becomes particularly important to conduct efficient and accurate nondestructive characterization of defects/damages formed during the whole life cycle. Due to the complex preparation and forming process of ceramic matrix composites and the high heterogeneity and anisotropy caused by multiphase composite, the traditional nondestructive testing technology based on the assumption of global homogenization faces many challenges. Based on the application of ceramic matrix composites in aero-engine field, the typical defect/damage types and characteristics in the whole life cycle of ceramic matrix composites were analyzed. The research progress and application of nondestructive characterization techniques of ceramic matrix composites in recent years were reviewed, the main challenges faced by existing nondestructive characterization techniques were summarized, and the future development trend was prospected.
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    2023,14(6):153-159. DOI: 10.16615/j.cnki.1674-8190.2023.06.17
    [Abstract] (215) [HTML] (26) [PDF 2.60 M] (10779)
    Abstract:
    The thermal field distribution of generator has a great influence on the failure phenomenon of the overheat protection component, which is the key parameter to be considered in the design. Based on the steady-state pressure solver and turbulence model in ANSYS software, the internal thermal field distribution of the motor under fault mode was simulated. The thermal field distribution of the stator, rotor and shell circulating oil circuit were obtained. The results show that the simulated thermal field is consistent with the actual temperature field distribution. The temperature gradient of low-melting alloy in the thermal trip mechanism is accordance with the internal thermal field distribution of the generator. It is helpful to protect the motor from overheating by changing the melting points of some key parts and the special softening temperature points of materials.
    [Abstract] (3250) [HTML] (0) [PDF 1.89 M] (6612)
    Abstract:
    Recently, with the continuous development and improvement of UAV technology, it not only plays an important role in the military field but also has been widely used in the civil field. However, the continuous reduction in the use of the UAV brings tremendous convenience to people"s life and production. At the same time, the abuse of UAV also pose a huge safety hazard to the country, society and citizens. Therefore, the demand for countermeasure and pro-tection against low-altitude drones is very strong in the military and civilian areas. This article focuses on the ap-plication of UAV in different fields, introduces the safety problems caused by UAVs flying at low altitude, and discusses the types and sources of threats. On this basis, this article focuses on the domestic and foreign anti-UAV technology in-depth analysis of the status quo, systematically on the existing anti-UAV technology and related systems, advantages and disadvantages are introduced. In addition, the future development trend of key technologies of detection and protection in low-altitude anti-aircraft UAV is analyzed and discussed based on the intelligent, integrated and autonomous research and development of low-altitude UAV systems.
    2021,12(3):161-170. DOI: 10.16615/j.cnki.1674-8190.2021.03.20
    [Abstract] (629) [HTML] (0) [PDF 8.07 M] (5159)
    Abstract:
    The process of folding and inflating the cylindrical airbag is complicated, and there are many inconveniences in using experimental methods to study its expansion process. Two different folding methods are proposed for the cylindrical airbag and the corresponding numerical analysis models are established respectively. The nonlinear dynamics software is used to study the dynamic application characteristics of the cylindrical airbag after being folded, which will affect the skin stress during the airbag expansion process. The factors of volume and internal pressure curve change are analyzed, and the influence of different folding methods and external environmental parameters on the dynamic characteristics of the cylindrical airbag is discussed. The results show that the two folding methods have their own advantages in storage space and material strength. In addition, in the environmental parameters, the external pressure has a greater impact on the stable state of the airbag after expansion, while the temperature has no obvious effect.
    2019,10(3):309-318. DOI: 10.16615/j.cnki.1674-8190.2019.03.003
    [Abstract] (1231) [HTML] (0) [PDF 1.21 M] (4021)
    Abstract:
    The Additive Manufacturing(3D Print) was widely studied and used in recent years, but there wasn"t a systematic, distinct and accurate classification about the Additive Manufacturing. The Additive Manufacturing was divided into 3 sorts and 13 sub sorts according to the category and state of the added materials and heat source of the manufacturing in this paper, as well as the principle, characteristics and trend of the each sorts of the Additive Manufacturing method were analyzed.
    [Abstract] (2516) [HTML] (0) [PDF 1.88 M] (3978)
    Abstract:
    To provide superior cruise thrust for high subsonic intermediate-long range missiles, small turbojet and turbofan engines have become the competitive focus for militarySpowers. The turbine engines for missiles are characteristic of low cost, short life, small size, high speed, low pressure ratio, severe volumetric heat release rate and various starting or ignition methods. They were widely equipped on strategic and tactical weapons, such as cruise, anti-ship and air-to-ground missiles. The development situation of small turbine engines within 100~700daN since 1970s is summarized and analyzed comprehensively in this paper, including well-known products, main technical parameters, basic features, application status and development trend. The study can provide references for the research work on missile propulsion systems. Lower cost, less fuel and fewer parts will be the future goals. The propfan engines have advantages of nice high subsonic performance and low fuel consumption, and the pulse detonation turbine engines possess high thermodynamic cycle efficiency and simple structure. They are both important development directions of advanced turbine engines for missiles.
    2014,5(1):109-115. DOI:
    [Abstract] (3923) [HTML] (0) [PDF 2.89 M] (3567)
    Abstract:
    For free turbine turboshaft engine with high thermodynamic parameters and high-bleed, a new turboshaft performance calculation model which considers bleed position and cooling air expansion work. The model of air bleeding in the middle of the compressor corrects the flow balance and power balance at the same time. The turbine cooling model considers the cooling air expansion work. The calculation results obtained by the new model are analyzed and compared with that of simple turbine bleed and cooling model, which proves that the new model can obtain the influence of the amount of bleeding and bleeding position to the performance of turboshaft engine. The new model are close to the true physical process of turboshaft engine, and can offer input to the air system.
    2018,9(1):99-106. DOI: 10.16615/j.cnki.1674-8190.2018.01.013
    [Abstract] (2198) [HTML] (0) [PDF 1.77 M] (3495)
    Abstract:
    A heavy-duty quadrotor UAV which has the features of foldable, light weight, high strength is designed according to the performance requirements. The maximum payload of this UAV is 10kg. The finite element model of the quadrotor structure is established. Static and buckling analysis of the UAV arm and central plate are carried out based on the actual loading cases. The layer structures of the arm and central plate are optimized. The strength, stiffness and stability of the UAV are verified. Compared with the initial layer structures, the weight of the arms drops by 43%, and the weight of the central plate drops by 35%. The weight of the UAV structure drops by 560 grams. The lowest weight requirement is achieved. An UAV static test platform is built, and the structure static loading test is completed. The strain relative error between the test value and the analysis value is less than 15%. The reliability of the UAV finite element model and the optimized layer structures is verified.
    [Abstract] (1844) [HTML] (0) [PDF 562.11 K] (3311)
    Abstract:
    There are a great deal of influence on many fields of society as a result of the new round of technological revolution and industrial revolution centered on artificial intelligence. All the aerospace powers have conducted many useful experiments and explorations in the combination of artificial intelligence and aerodynamics. The development history and status quo of artificial intelligence technology are reviewed in this paper, the applications of artificial intelligence in wind tunnel test, numerical calculation and flight test are discussed in the background of big data era, the role of artificial intelligence in assisting mass aerodynamic data analysis and knowledge discovery is analyzed in detail, the application values of artificial intelligence in aerodynamic modeling and advanced aircraft design are investigated, the future development direction and challenges of combination of artificial intelligence and aerodynamics are prospected.
    2013,4(2):158-163. DOI:
    [Abstract] (3642) [HTML] (0) [PDF 4.91 M] (3076)
    Abstract:
    Weight is one of the most important performances for the aviation productions. The most effective approach to weight saving is developing the lower density material. Introduce advanced Al-Li (Aluminum-Lithium) alloy with lower density, higher tensile strength, better damage tolerance etc. Compare to conventional aluminum alloys and trade-off study with advanced composites. Analysis the properties of 3rd-generation Al-Li alloy and the applications on advanced aircraft. Provide the proposals of applications in civil program. The research can be the reference of materials selection and weight saving for commercial aircraft, and benefit extending applications of Al-Li alloy.
    2020,11(2):147-158. DOI: 10.16615/j.cnki.1674-8190.2020.02.001
    [Abstract] (1534) [HTML] (0) [PDF 3.27 M] (2877)
    Abstract:
    To reasonably and efficiently guide the safe, reliable and economical operation of civil aircraft, we investigate the main contents and explore the application in operational reliability analysis and feedback of S5000F, i.e., international specification for in-service data feedback, which is organized by AeroSpace and Defence Industries Association of Europe (ASD). The compilation background and purpose of S5000F specification are first elaborated, and the main contents and the relevant business processes in the S5000F specification were then introduced. We finally discussed the application of S5000F specification in the operational reliability analysis and feedback of civil aircraft. In this paper, the S5000F specification is comprehensively interpreted, and its application in the operational reliability of civil aircraft is studied. In this case, we further extend this specification to the design phase and service phase of civil aircraft. The efforts of this study provide effective guidance for the life cycle management of civil aircraft.
    2013,4(2):241-246. DOI:
    [Abstract] (2393) [HTML] (0) [PDF 2.31 M] (2704)
    Abstract:
    In this paper, an approximation method is presented for calculating the wing load envelope and using to size the wing box in wing strength primary design phase. It is found that the triangle weight load distribution is better than other distributions in simulating the wing weight. Furthermore, this paper investigates the characters of critical over loading and centralized loads for large civil aircrafts. An approximation method for calculating the wing load envelope of bending moment and shear force in flight is proposed by combining the Schrenk lift distribution and triangle weight distribution. Then, the proposed method is validated by wind tunnel data of wing shear forces and bending moments.
    [Abstract] (1703) [HTML] (0) [PDF 2.40 M] (2657)
    Abstract:
    Reducing the weight and increasing the torsion stiffness are the two main pursuits in propeller blade structure design. And the application of composite materials has improved the designability of propeller structure. In this paper we present an optimization process on a composite propeller blade, in which the composite layup numbers and angles are optimization parameters, the strength and bending stiffness are optimization constraints and the weight and torsion stiffness are optimization objectives. Non-dominated Sorting Genetic Algorithm is adopted to get a Pareto front of the two objectives. Results show that the optimization method is effective.
    Abstract:
    Bayesian Network(BN) is a mathematical model based on probabilistic reasoning, which have a great advantages in solving the uncertainties between complex systems. Because of the complexity and uncertainty in air-combat, aiming at the problems in effectiveness evaluation, combined with the air-combat theory and reality. The effectiveness evaluation model of air-combat based on BN is build, the effectiveness evaluation method of air-combat based on BN is given, and simulation analysis is carried out. The results show that the model is valid and accurate, and the method has a strong ability to learn and reasoning.
    2020,11(2):159-166. DOI: 10.16615/j.cnki.1674-8190.2020.02.002
    [Abstract] (1328) [HTML] (0) [PDF 1.20 M] (2471)
    Abstract:
    High Altitude Long Endurance (HALE in short ) UAV has made great development since its birth and participation in war. With the expansion of combat mission to high-risk confrontation battlefield, HALE fly-wing UAV has become a hotspot in the world today. In this paper,the requirements of HALE fly-wing UAV for turbofan engine are described, effect of key design parameters on the performance of turban engine is analyzed based on the basic principle of aero engine, the key problems and research progress of HALE fly-wing UAV are summarized. This paper has important reference value of the selection of turbofan engine for HALE fly-wing UAV and the improvement of its adaptability design.
    2021,12(4):80-89. DOI: 10.16615/j.cnki.1674-8190.2021.04.09
    [Abstract] (487) [HTML] (0) [PDF 4.02 M] (2471)
    Abstract:
    The effect of thermal load in the creep feed grinding have important effect on the surface quality for ma? chining the tenon teeth of turbine blade. In this paper,the effects of grinding parameters on grinding forces and temperature in grinding DD5 single crystal alloy are investigated by experiments. The influences and formation mechanism of DD5 creep-feed grinding forces and temperatures are analyzed,and a mapping model between thermodynamic effect and grinding parameters is established and verified. The experimental results show that the grinding depth has the greatest influence on the DD5 creep-feed grinding force and temperature,following by the grinding wheel speed,and the feed velocity of work-piece has less influence on the grinding forces and temperature. With the increase of the grinding wheel speed,the grinding force is decreasing,and the grinding temperature has an in?creasing trend. With the increase of feed velocity and grinding depth,both the grinding force and temperature are of increasing trends. Increasing the feed velocity and reducing the grinding depth on the premise of satisfying the material removal rate can avoid the larger grinding thermodynamic coupling layer on the DD5 grinding surface.
    2014,5(1):1-6. DOI:
    [Abstract] (3035) [HTML] (0) [PDF 6.43 M] (2433)
    Abstract:
    Fuel tank damage caused by hydrodynamic ram has became increasingly widespread. Summary and analysis of the research of hydrodynamic ram in recent decades provide a reference for future research work. Hydrodynamic ram research has an early start, early experiment and theoretical analysis formed the theoretical basis. With the progress of the test apparatus and the introduction of finite element method, test results has became more and more accuracy, hydrodynamic ram effect research entered a new phase. But for the hydrodynamic ram effect, there are so many problems, they will be the focus of future work.
    2021,12(4):44-51. DOI: 10.16615/j.cnki.1674-8190.2021.04.05
    [Abstract] (1012) [HTML] (0) [PDF 5.62 M] (2337)
    Abstract:
    Rotor airfoil design involves multi-point and multi-objective complex constraints. How to significantly improve the maximum lift coefficient and maximum lift-to-drag ratio of rotor airfoil is a fundamental problem to be solved urgently in the development of high-performance helicopter rotor blades in the future. Novel flow control technology is the most potential method to achieve the high lift enhancement and drag reduction of rotor airfoil. Based on the classic OA312 rotor airfoil, this paper conducts the low-speed wind tunnel test of high lift enhancement and drag reduction of rotor airfoil using Co-flow Jet concept (CFJ) with zero mass and high negative pressure at the leading edge. The rotor airfoil CFJ dynamometric model driven by the micro ducted fan group is designed. The influence of basic parameters such as the injection size, suction size and suction surface translation on lift enhancement and drag reduction is studied. The ratio of jet velocity to mainflow velocity is qualitatively discussed. The optimal value range of key parameters of CFJ rotor airfoil is given. Results show that compared with the OA312 baseline airfoil, the CFJ rotor airfoil can significantly reduce drag coefficients at low angle of attack, and even achieve while the zero-lift pitch moment is basically unchanged. The CFJ rotor airfoil can significantly increase the maximum lift coefficient and the stall angle of attack at high angle of attack. The maximum lift coefficient can be increased by about 67.5%, and the stall angle of attack is significantly delayed by nearly 14.8°. Research results verify the technical feasibility of applying CFJ technology to significantly improve the key performance of rotor airfoil and provide a new feasible solution and idea for the design of high-performance rotor blades in the future.
    2018,9(3):297-308. DOI: 10.16615/j.cnki.1674-8190.2018.03.001
    [Abstract] (1329) [HTML] (0) [PDF 3.91 M] (2297)
    Abstract:
    This paper focuses on the research on the status of adaptive wing and summarizes from the adaptive compliant leading edge, the adaptive compliant trailing edge and the variable thickness wing, respectively. And the key technology that adaptive wing needs to be solved urgently is put forward, which can provide some technical reference for the design and implementation of adaptive wing structure.
    [Abstract] (1336) [HTML] (0) [PDF 1.78 M] (2295)
    Abstract:
    In order to calculate the contact force of the flight lock mechanism, the function and main design basis of flight lock are firstly introduced in this paper. Then the working principle of the flight lock for a specific civil airplane is illustrated, following with the analysis of its force transmission path. Then three calculation methods (engineering method, rigid multi-body model, and flexible multi-body model) are used to compute the contact force between crank and rocker arm. Finally the three calculation methods are compared and analyzed to find out the reasons of the differences between the contact forces for each methods. The results shows that the arm variation caused by mechanism banking leads to the difference between the forces calculated by engineering method and rigid multi-body model. On the other hand, structure deformation is the main factor that causes the difference between the forces calculated by rigid multi-body model and flexible multi-body model. These analysis results can be consulted for the structural design of civil airplane’s flight lock.
    2013,4(3). DOI:
    [Abstract] (2843) [HTML] (0) [PDF 3.09 M] (2243)
    Abstract:
    According to the folding wing morphing aircraft, designed a planetary gear train of folding mechanism, which suit assembly in the small space of morphing aircraft. On the basis of the systematic study of the planetary gear design goals, variables and constraints, describes the floating-point coded genetic algorithm, using the MATLAB optimization toolbox to optimize its main parameters. Research shows that the structure weight loss 16.7% compared with the safety coefficient method, achieve the minimum weight of the folding mechanism in the case of meeting the design specifications. Therefore the floating-point coded genetic algorithm optimization solution for planetary gear mechanism design is an effective optimal design method.

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