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Abstract The present hybrid vortex tube-vorton method is based entirely on the Full Multi-wake Vortex Lattice Method (FMVLM) concepts, which means detaching vorticity with precise vortex strength and orientation along all separation lines between each discretized element of a shell-body, including all external edges. Since the classic Vortex Particle Method (VPM) is unstable by itself because it does not conserve the total amount of circulation as time evolves (Kelvin’s circulation theorem), an isolated Vortex (regularized) Filament Method (VFM) approach is implemented to obtain advection of vorticity, while the induced velocity field is obtained through its corresponding full vorton cloud. Further, a novel vortex squeezing/stretching scheme for such a vortex cylinder-sphere approach is proposed based on variation in time for vortex volumes in order to precisely (zero residual) conserve both circulation and vorticity at each time step (for each detached vortex element), while the viscous effect can be accounted for via the Core Spreading Method (CSM).

The issue of improving energy-mass characteristics is one of the most important ones in the development of gas generators for various purposes. In this regard, as part of the search for ways to use promising types of fuels, experimental studies of gas generators operating on composite mono-fuel based on nitrate esters were carried out. As a device initiating the combustion reaction, a granular self-heating heat accumulator was used, which was placed in a cylindrical combustion chamber. Experimental studies made it possible to reveal the features of a complex and multi-stage process of mono-fuel conversion occurring in the pore space of the gas generator combustion chamber on the surfaces of the granules and inside a complex system of channels consisting of elementary cells formed by these granules. In this case, the pore space of the heat accumulator is granular filling of mono-dispersed granules of a disordered structure. The task of the work described in the article was to create a mathematical description of granular filling of a disordered structure, solved in a two-dimensional formulation. The article proposes a method of transition from hexagonal stacking to conditionally ordered one that combines the compactness of hexagonal stacking and the ease of description of cubic stacking. The resulting stacking makes it possible to represent half of the frontal section of the granular heat accumulator in the form of a vertical flat layer with a given structure determined by porosity, granule diameter and dimensions of the combustion chamber – its length and diameter. The proposed approach for the transition from a disordered filling structure to a conditionally ordered structure made it possible to develop a mathematical model that describes the internal structure of the launch heat accumulator and determine the coordinates of the heat accumulator zones in which various stages of monopropellant conversion take place. This will allow us to proceed to the formation of a description of the working process of gas generators with a granular self-heating heat launch accumulator.

The effect of broadband disturbances on the operation of a noise-immune digital speckle pattern interferometer with a continuous wave laser emitter and a diffuse-scattering element arranged in front of an oscillating turbine wheel has been studied. Visibility dependences of the recorded interference patterns were obtained under the action of different types of artificially created disturbances. It is shown that the most dangerous mechanical disturbances for the operation of a speckle pattern interferometer are periodic noise and pink noise, whereas white noise and natural vibrations of the floor in the room where the experimental setup was accommodated do not significantly influence the quality of the information recorded by the interferometer. This article analyzes the influence of the mechanical properties of the diffuse-scattering element arranged in the speckle pattern interferometer on the quality of the obtained interference patterns. A relationship between the growth of forced tangential oscillations of the diffuse-scattering element and a decrease in the contrast of interference fringes was noted. In this case, an increase in the thickness of the organic glass plate of the diffuse-scattering element up to 8 mm leads to the neutralization of the pink noise action on the speckle pattern interferometer operation. At the same time, the effect of periodic noises decreases the contrast of interference patterns recorded for the cases of using 5 mm and 8 mm thick organic glass plates.

This paper discusses a composite material from chopped thin narrow polymer tapes reinforced with carbon fibers and a polymer binder. The problem is posed to analytically determine the elastic and strength characteristics of the composite with a known minimum set of basic characteristics of the components. A methodology for sequential solving of the problem at the micro- and meso-levels is proposed. The key point in the methodology is the introduction of the “effective fiber volume factor” in the short filament and the way to calculate it using the “load-carrying factor” criterion. The following are presented: the results of calculating Young’s modulus and tensile strength of material samples from parts of tapes with fixed lengths (6, 12, 18 and 24 mm); comparison with the experimental data and evaluation of accuracy and limits of the applicability of this methodology.

The paper describes possibilities of increasing the energy efficiency and reducing the takeoff weight of unmanned medium-heavy vertical takeoff and landing aerial vehicles of the airplane type. The authors propose a new hybrid type of unmanned aerial vehicle with a hybrid propulsion system, its aerodynamic design, method of realization of vertical takeoff/landing and cruising mode of flight which make it possible to reduce the takeoff weight of the aircraft, the weight of the basic propulsion system and the mass growth factor in comparison with the existing unmanned aerial vehicle of similar class, made according to the previously known technical solutions. The authors propose a methodology for optimizing the parameters of the configuration of the unmanned aerial vehicle considering the peculiarities of the implementation of vertical takeoff. The paper presents calculations of characteristics of vertical takeoff and landing unmanned aerial vehicles of existing types and the new hybrid type. The authors give quantitative estimates of improving unmanned aerial vehicle characteristics due to the new proposed technical solutions.

A study of combustion characteristics in a swirling jet was carried out from the perspective of the theory of turbulent combustion. Particular attention is paid to the reverse-flow area formed from the vane swirler. Based on the known composition of the mixture, the parameters of the speed of propagation of the flame front, completeness of combustion, temperature and emission of nitrogen oxides are successively determined. The created analytical technique was tested in the combustion range of inhomogeneous and homogeneous mixtures. Calculations showed the dependence of emission on the mixing parameters.

A generalized kinematic scheme of the installation of quadcopter motors is presented and its main advantages are described. In accordance with the scheme, a mathematical model of the kinematics of the quadcopter was developed. The model was implemented in the MatLab software environment. The presented mathematical expressions are used to calculate kinematic characteristics, such as the values of the thrust of the motors and the reverse effect of the motors on the body of the quadcopter. The comparison of the obtained data with the experimental characteristics showed a 5% deviation of the magnitude of the dependence of the thrust on the average value of the voltage on the motors and a 30% deviation of the magnitude of the dependence of the motor action on the thrust magnitude.

The article presents the results of a study on the basis of which a set of mathematical models was developed for ballistic analysis of a mission to send a small spacecraft to the satellite of Jupiter, Callisto and its landing on the surface of the satellite. In this mission, it is proposed to use a gravity assist maneuver around the Earth and an aerodynamic maneuver near Jupiter to reduce the cost of the working fluid of the spacecraft. The minimum required thrust of the engines and the duration of the soft landing maneuver of a spacecraft with a given mass on the satellite are estimated. The optimal launch date was found for the possibility of launching a spacecraft using a medium-lift Soyuz-2 launch vehicle. The simulation of the movement was carried out numerically, in the Mathcad mathematical package, all the dependence diagrams necessary for the analysis of the movement were constructed.

The problems of optimizing the trajectory motion of the first stage of an aerospace system according to the criterion of the maximum of the final mass are considered. The control is the angle of attack and thrust of the engines. Control optimization is carried out on the trajectory section from the point of bringing the first stage to the launch area until the motion parameters required for separation of the space stage are reached. The Pontryagin’s maximum principle is used to determine optimal control programs. The solution of the problem without restrictions on the modes of motion is carried out using the example of acceleration and climb of the first stage of the RASCAL aerospace system. A method is proposed for determining approximate optimal control in a problem with a limitation on the altitude range of the engines with separate optimization of the active and passive sections and the search for the optimal point of their coupling. Changes in control program, trajectory, and fuel consumption are discussed when limiting the maximum flight altitude in the active section.

The main purpose of the article is to identify the main approaches and define the concept when modeling the hydro-mechanical control systems of an aircraft. The advantages and importance of a computational experiment with the aid of a virtual test bed at the stage of constructive parametric debugging of the elements of complex hydraulic systems are emphasized. The characteristics obtained from the results of the computational experiment will allow us to determine the level of adequacy of the models and subsequently choose the most optimal design and operational parameters.

One of the most important gas turbine engine components is the combustion chamber, the main source of harmful emissions. The study is devoted to the central issues of designing and testing of an automatic control system of harmful emissions and pressure pulsations in flame tubes of a gas turbine plant with a capacity of 16 MW GTP-16 based on a PI-controller with a built-in neural network mathematical model of a low-emission combustor (LEС). Algorithms for a neural network controller of emission of nitrogen oxides and carbon monoxide into the atmosphere, as well as pressure pulsations in the LEC’s flame tubes were developed. The algorithms are given in a graphical programming environment and integrated into the automatic control system of GTP-16, implemented on the PXI NI hardware and software platform. The performance of the emission controller was checked during bench tests on the GTP-16 simulator with LEС neural network model serving as a virtual emission sensor. The errors in estimating the emission of nitrogen and carbon oxides and pressure pulsations in the flame tubes were determined. The normality of the error distribution of the developed nitrogen oxide emission model was proven. A conclusion about the prospects of using neural networks for the development of an adaptive control system of emissions and flame tube pressure pulsations for LECs of the gas turbine plants was drawn.

Six alloys of the Al-Ca-Zn-Mg system with additives of copper, manganese, iron and silicon were studied in order to simulate the composition of an alloy prepared on the basis of secondary aluminum. The alloys were made in the form of ingots with dimensions of 140×200×20 mm that were subjected to subsequent deformation treatment by hot rolling from a thickness of 20 mm to a thickness of 1 mm, and then cold-rolled sheets with a thickness of 0.5 mm were obtained from them. A cylindrical ingot with a diameter of 40 mm and a length of 200 mm was also made. Rods with a diameter of 14 mm were obtained from it by radial displacement rolling. Hot deformation treatment of ingots was carried out at a temperature of 450°C without prior homogenizing annealing. Cast and deformed specimens were examined using optical and scanning electron microscopy. No coarse acicular particles of iron- and silicon-containing phases, as well as any other coarse intermetallides, were found in the microstructure of the specimens. Mechanical tests were carried out using the method of uniaxial tension of deformed semi-finished products that were not subjected to additional strengthening heat treatment. According to the test results, an alloy of optimal composition was selected. The possibility of obtaining products from high-strength and high-tech aluminum-calcium alloy based on secondary raw materials without the use of homogenization and quenching was established.

The power supply system being created is intended to provide electricity to spacecraft systems. It ensures that the design characteristics of the solar battery of the prototype are preserved and makes it possible to install means to support the thermal conditions of the photovoltaic battery while maintaining the cost of production of the prototype solar battery. Various types of solar energy concentrators are considered: concentrators in the form of individual convex linear Fresnel lenses, Flexible Array Concentrator Technology concentrators, Stretched Lens Array concentrators. A method for improving the characteristics of the spacecraft solar system is presented. The methodology includes the calculation of various types of concentrators, types of photovoltaic converters and types of solar battery frames. As an example of the implementation of the methodology, the design of solar battery panels was developed. A comparative table of the solar battery before and after modernization is provided.

The study addresses the effect of 1580 and 1590 alloys cold rolled strip annealing practices on the alloys’ grain structure and mechanical properties. The 1590 alloy differs from the 1580 alloy by hafnium and erbium additions. Samples of such alloys were produced by casting into a steel mold. After that they were homogenized during 4 h at 440°С. Then the samples were hot rolled at 440°С, with further cold rolling to 2 mm, with the cumulative percentage reduction equal to 66%. The cold rolled strip was annealed at the temperature ranging from 330 to 440°С with 1 h soaking. The sizes and morphology of Al3Sc strengthening nanoparticles were examined in homogenized condition using transmission microscopy. The mechanical properties and grain structure were defined in cold rolled and annealed conditions. During homogenizing annealing in the 1590 alloy finer strengthening nanoparticles are formed compared to the 1580 alloy. Such features of the microstructure can be explained by the presence of erbium, promoting formation of additional Al3Sc-type nanoparticles nuclei, and hafnium, preventing their further growth. Non-recrystallized structure was identified in both alloys after cold rolling and final annealing. The 1590 alloy has better mechanical properties, regardless of the annealing temperature, which is explained by a larger portion and smaller size of strengthening nanoparticles.

A method for developing a numerical rotor model and its further verification based on the results of virtual static structural and modal tests was proposed. Approbation of the method was performed on a model of a low pressure rotor of a high-bypass turbofan engine constructed in a software system for rotor dynamics simulation DYNAMICS R4. Refined on the basis of the results of virtual static structural tests, the model of the rotor main force action line showed good agreement in frequencies and mode shapes with the results of a finite element model, obtained during a virtual modal test.

The article presents the results of a study of the elemental composition, surface morphology, optical and electronic properties of Mg2Si thin films formed on Si (111). Both samples containing films were formed in layers by the method of reactive epitaxy, but at different heating temperatures of the substrates. The formed films consisting of alternating layers of Mg and Si at a ratio of 3:1, according to electron Auger spectroscopy, contain Mg and Si atoms in the associated layers. The Raman light scattering method established the presence of peaks on the graphs of samples at a shift of 258 and 348cm-1 belonging to Mg2Si. Infrared spectroscopy data also indicate the presence of magnesium silicide in the films. The thickness of Mg2Si films was estimated from the data of the known dependence of the amplitude of absorption peaks at 272 cm-1 on the absorption coefficient, which gave the values of the thicknesses of the grown films. Based on the results of the study of samples in the infrared-ultraviolet range and on the basis of geometric calculations, the width of the Mg2Si band gap was determined.

Abstract Aiming to efficiently simulate the transient process of transpiration cooling with phase change and reveal the convection mechanism between fluid and porous media particles in a continuum scale, a new two-phase mixture model is developed by incorporating the local thermal non-equilibrium effect. Considering the low-pressure and high overload working conditions of hypersonic flying, the heat and mass transfer induced by capillary and inertial body forces are analyzed for sub-cooled, saturated and super-heated states of water coolant under varying saturation pressures. After the validation of the model, transient simulations for different external factors, including spatially-varied heat flux, coolant mass flux, time-dependent external pressure and aircraft acceleration are conducted. The results show that the vapor blockage patterns at the outlet are highly dependent on the injection mass flux value and the external pressure, and the reduced saturation temperature at low external pressure leads to early boiling off and vapor blockage. The motion of flying has a large influence on the cooling effect, as the inertial force could change the flow pattern of the fluid inside significantly. The comparison of the results from 2-D and 3-D simulations suggests that 3-D simulation shall be conducted for practical application of transpiration cooling, as the thermal protection efficiency may be overestimated by the 2-D results due to the assumption of an infinite width length of the porous plate.

With the proposal of the "dual carbon”goals，using hydrogen as zero-carbon alternative fuel has become an important trend of the aviation industry in the future. In recent years，the hydrogen-fueled aero-engines have garnered significant attention. Superalloys are the most widely used materials in the hot section components of gas turbine engines. The purpose of this review is to provide reference for the research and development of superalloys for hydrogen-fueled aero-engines future use by understanding the effects of hydrogen-related environment on superalloys currently across various fields. Internal/external hydrogen environments，hydrogen permeation（charging）methods，measurement of hydrogen concentration/distribution or stable existence temperature，the influence of hydrogen on tensile strength，the impact of hydrogen on creep/stress rupture and fatigue properties，and the fracture mechanism of hydrogen embrittlement are described. The degradation factors of mechanical properties of superalloys with different composition，manufacturing process，original microstructure，alloying degree and different application fields under hydrogen-related environment are summarized. In general, mechanical properties tests in the external hydrogen environment exhibit more significant hydrogen-assisted mechanical degradations than that in internal hydrogen environments. Superalloys with higher alloying degree exhibit more pronounced hydrogen embrittlement，while the tendency of properties decrease（creep/rupture，fatigue and tensile）in hydrogen at elevated temperature is much less than that at room temperature. The prospects for the mechanical performance evaluation of current superalloys in hydrogen-related environments for hydrogen-fueled gas turbine and the development of new alloys suitable for hydrogen environments are provided. Hydrogen-fueled gas turbine aero-engines may encounter cryogenic temperature hydrogen environment for liquid hydrogen storage，hydrogen environment for cooling，high-temperature/high-pressure hydrogen environment for gas compression，and the impact of combustion products–water vapor（humid）at elevated temperature. Diffusion or permeation of hydrogen in superalloys，the embrittlement and corrosion of alloys in high-pressure hydrogen environments，oxidation and corrosion behavior in high-temperature humid environments，as well as the degradation and protection mechanism for alloys and coatings in the aforementioned multiple coupling environments shall be concerned. It is necessary to establish hydrogen combustion environment experimental facility that closely simulates service conditions to conduct research on the impact of hydrogen-related environment on superalloys and their components. It is also essential to establish a mechanical performance database and standards for currently used key materials in hot section components such as turbine blades and disks for hydrogen related environments，and properly develop new high-temperature structural materials suitable for hydrogen combustion conditions，which will provide support for the application of hydrogen fueled gas turbine aero-engines.

Ultra-high strength aluminum alloy has achieved extensive application in the nuclear，aerospace，and aviation industries because of its high specific strength and low density. The fifth generation of ultra-high strength aluminum alloy has been produced，and in comparison to the fourth generation’s 600 MPa level，its ultimate strength has been consistently redefined and increased from 650-700 MPa to 750 MPa or even 800 MPa. This paper reviews the history of the research on aluminum alloys with ultra-high strengths and introduces the current state of development both domestically and internationally. The key issues and recent research development are further explored，including computer simulation，thermal deformation，heat treatment，homogenization，melting，and casting，as well as composition design. Finally，combined with the development needs of future equipment and domestic technology status，it is pointed out that in-depth study of basic theory to solve the problem of comprehensive performance matching，the promotion and application of special materials in specific application scenarios are the development trend and important direction of ultra-high strength aluminum alloy.

Advanced materials technology is the forerunner in the development of high-tech aerospace equipment and the key foundational technology supporting the modern industry. It has penetrated into all aspects of national defense construction，national economy and social life，and has become a technological highland and national defense focus that countries all around the world are competing to develop. This article focuses on analyzing the current technological status and development trend of the advanced structural materials in the aerospace field，elaborating on the aspects of high-performance polymer and their composites，high-temperature and special metal structural materials，lightweight high-strength metals and their composites，and advanced structural ceramics and their composites. The analysis results show that the current development and production of aerospace structural materials in China still face various difficulties，such as too much follow-up research and imitation，lack of independent innovation，severe technological blockade，and technical bottlenecks need to be broken. Meanwhile，the prospects for future research and development are proposed，and the significance of establishing the complete technology system of production-learning-research-application is highlighted.

The high temperature deformation behavior of vacuum powder forging FGH95 alloy was studied by Gleeble-3800 thermal simulation testing machine. The hot compression test was carried out at the deformation temperature of 1090-1170 ℃ and the strain rate of 0.01-10 s−1. The flow stress-strain curves under the corresponding conditions were obtained. The effects of deformation conditions on the microstructure evolution of vacuum powder forging FGH95 alloy were analyzed by EBSD. After considering the influence of temperature，strain rate and strain on the flow behavior of the alloy，the Arrhenius equation was selected to establish the constitutive model of vacuum powder forging FGH95 alloy，and the parameters of vacuum powder forging FGH95 alloy were obtained. The relationship between material parameters and strain was fitted and the obtained constitutive equation was verified.The results show that the flow stress of FGH95 alloy prepared by vacuum powder forging process decreases with the increase of temperature and increases with the increase of strain rate. The size of recrystallized grains in the deformed microstructure decreases with the increase of temperature and increases with the decrease of strain rate. The error between the predicted value and the experimental value of the flow stress of the vacuum powder forging FGH95 alloy is 6.33%，and the predicted value is in good agreement with the experimental value.

The precipitation behavior of secondary α phase and mechanical properties of high strength TB9 titanium alloy were investigated during single aging and duplex aging. The alloy phase constitution was analyzed by XRD，and the microstructure was observed by optical microscopy and scanning electron microscopy. The evolution characteristics of the microstructure with aging temperature were mainly analyzed. The room temperature tensile properties and fracture toughness were tested. The research results indicate that during single aging，secondary α phase exhibits serrated and layered precipitation. With increasing aging temperature，the size of α phase increases，and the content of layered α phase increases. The strength at 430 ℃ aging is lower and the plasticity is higher. The strength at 470 ℃ aging is the highest. With increasing aging temperature，the strength first increases and then maintains at the similar level. During duplex aging，most of secondary α phases precipitate in a serrated shape within the grains. With increasing aging temperature，the size of α phase increases，the tensile strength first increases and then decreases，reaching a maximum of 1542 MPa. The tensile strength of duplex aging is significantly higher than that of single aging，which is mainly due to the combined strengthening effect of second phases near grain boundaries and intragranular α phases with serrated shape.

Additive manufacturing provides a new way to develop high-performance superalloys and components. A γ′- strengthened CoNi-base superalloy suitable for additive manufacturing was developed，and a crack-free block material was prepared by optimizing the parameters of electron beam melting（EBM） technology. The experimental results show that the lowest porosity of the alloy is about 0.14% when the scanning speed is 2000 mm/s. The microstructures of the as-printed CoNi-base alloy are columnar grains growing along the direction，the average grain width is about 235 μm，and the volume fraction of γ′ phase is about 30%. After hot isostatic pressing and solution aging treatment，the porosity of the alloy is further reduced to about 0.09% with unobvious change of columnar grains. The average size of γ′ phases is about （70±18）nm with the volume fraction of about （32±3.6）%. The results of room temperature tensile tests show that the additive manufactured γʹ-strengthened CoNi-base superalloy exhibits excellent strength and ductility，showing a good potential of industrial application.

In view of the shortage of conventional design methods of pressure curve in the anti-gravity precision casting and taking the structural characteristics of the casting with variable cross-sections into account, automatic calculation of cross-sectional areas was implemented for the casting and gating system by the secondary development of CAD software, and quantitatively describing the variable feature of cross-sections of casting was realized. Based on Bernoulli and flow conservation equations，the relationship between the filling pressure and the rising speed of metal liquid level was deduced. A new design method of pressure curve based on the automatic calculation of cross-sectional areas of the casting was proposed. The simulation results of anti-gravity casting for nickel-based superalloy demonstrate that, compared with the pressure curve of the conventional design method，the new curve can reduce the peak value of filling speed from 0.611 m/s to 0.439 m/s at the minimum cross-sectional area，the falling range of which is 28.15%. It meant that the new method can effectively avoid the shock and splash of liquid metal，meanwhile，shorten the filling time，then the filling process is fast and stable. The hydraulic experiment and pouring experiment show that the new pressure curve has a smoother filling liquid level and can effectively avoid casting defects. Therefore，it proves the effectiveness of the new pressure curve design method and provides a basis for rational design of anti-gravity pressure curve.

With the improvement of thrust-to-weight ratio and other properties of future aero-engine，the high temperature mechanical property and structural stability of titanium alloy components are required. The limitation of traditional experiments in time and space scale has become increasingly prominent，and it is difficult to deeply study the microscopic transient phenomena and mechanisms. Moreover，the molecular dynamics（MD）calculation method takes the atomic/molecular model as the calculation object，on the basis of Newton classical mechanics and empirical parameters，the calculation efficiency is greatly improved compared with the quantum calculation method. Therefore，MD has become an important method to optimize the process parameters and calculate the microstructure properties of aero-engine titanium alloy. Based on an overview of the basic principle of MD computing space and time scale advantages，this paper reviews the relevant domestic and foreign achievements in the study of molding，microstructure characterization and performance testing of aero-engine titanium alloys by MD method in recent years，as well as representative conclusions that contribute to the improvement of high temperature resistance of aero-engine titanium alloys. Finally，the future prospect is discussed based on the demand for MD computing technology for aircraft engine titanium alloys，thus pointing out the challenges faced on the following aspects，including high-throughput composition design based on MD computing method，training molecular force fields for mature titanium alloy systems，and introducing the new ReaxFF（Reactive Force Field）into the study of combustion mechanisms.

High strength Ti-5Al-3Mo-3V-2Zr-2Cr-1Nb-1Fe（Ti-5321） alloy is a new type of high strength tolerance titanium alloy designed and developed to meet the demand of high performance titanium alloy for new generation aircraft in China. Ti-5321 alloy with equiaxed microstructure（EM），basket-weave microstructure（BW） and fine basket-weave microstructure（F-BW）was obtained by forging and heat treatment，and the tensile properties and fatigue crack growth behavior were studied. Fatigue crack propagation mechanisms in Paris and unstable propagation regimes were revealed by analyzing the microstructures and fracture morphology using optical microscopy (OM) and scanning electron microscopy (SEM). The results show that the samples with EM，BW and F-BW exhibit the excellent fatigue crack propagation resistance with the tensile strength of 1200 MPa. The sample with F-BW presents the highest fatigue crack propagation resistance in Paris and rapid growth regimes，while the sample with EM presents the lowest fatigue crack propagation resistance. In F-BW， the crack mainly propagates through and along α phase. Crack tends to propagate across colony oriented for （\begin{document}$ \bar{1} 011$\end{document}） pyramidal slip and propagates along colony oriented for （\begin{document}$10 \bar{1} 0$\end{document}） prismatic planes.

Heterocyclic aramid refers to a type of para-aramid containing aromatic heterocycles（usually benzimidazole units） in the main chain，which has excellent properties of lightweight，high strength and modulus，high thermal resistance and good solvent resistance. Compared to the typical aramid fiber Ⅱ，heterocyclic aramid exhibits superior mechanical properties and has been practically applied in the fields such as aerospace and bulletproof protection in China. However，similar to other organic fibers，the composite performance of heterocyclic aramids with resins is relatively low due to their inert surface，which limits their application in the field of advanced composite materials. This article from two aspects of surface modification and structural design，the design ideas，technical means and research results to enhance the composite performance of heterocyclic aramids in recent years are summarized，and the development trend of its application in the field of advanced composite materials is forecast，so as to provide assistance and reference for the interface design and improvement of interfacial adhesion of organic fibers.

Superalloys are predominantly employed to crucial aviation hot-end components such as turbine rear casings，diffusers，and pre-swirl nozzles. The investment casting technology supersedes “casting + welding” forming approaches，which reduces the number of parts and processing procedures，offers improved reliability and mass reduction. Therefore，investment casting is a pivotal technology for aviation component manufacturing. However，the casting of complex thin-walled components encounters challenges with dimensional accuracy，impacting engine aerodynamic performance and assembly precision，which has become a bottleneck problem restricting the manufacturing quality of key structural components of aero-engines in China for a long time. This article reviews the current advancement in the dimensional accuracy control for superalloy investment castings at home and abroad. A forward-looking analysis and discussion on development trends are conducted，particularly focusing on digital and intelligent technologies. There is an urgent need to build a digital twin platform for investment casting in the future and to develop more advanced accurate，quantitative and intelligent prediction methods for dimensional deformation and die profile design theory.

The AlSi10Mg alloy samples were successfully prepared by laser powder bed fusion（LPBF）. The effects of three kinds of heat treatment process，namely 130 ℃/4 h aging treatment，236 ℃/10 h annealing treatment，and 540 ℃/1 h solid solution treatment on the microstructure of the AlSi10Mg samples were investigated. After heat treatment，the evolution of coefficient of thermal expansion（CTE） and thermal conductivity of the AlSi10Mg alloy in the temperature range from room temperature to 400 ℃ was examined. The results show that spherical Si particles are precipitated within the aluminum matrix，while the complete network-like eutectic silicon structure is retained after aging treatment. After annealing，the network-like silicon structure is disappeared completely，and spherical Si particles are uniformly distributed within the matrix. After solution treatment，large blocky Si particles with the sizes from 1 μm to 3 μm appear. The thermal properties of the AlSi10Mg alloy have been improved significantly after heat treatment compared to the as-printed state. In particular，the CTE of alloy subjected to annealing is 1.64×10−5 ℃−1 to 2.1×10−5 ℃−1 within the temperature range from room temperature to 400 ℃，the average thermal conductivity is 179.6 W·m−1·K−1，the performance is superior to ageing and solution treatments.

The miniaturization and lightweight development of aerospace systems have raised higher requirements for the strength and ductility of power shaft materials. In order to develop maraging steel with the strength exceeded 3 GPa，an experimental maraging steel with high contents of Co，Ni，and Mo elements was designed. Its chemical composition is 4Ni-15Co-9Mo-0.86Ti-0.35Al-Fe. Through the high-temperature and large-scale plastic deformation with forging ratio greater than 10，the grains were refined as much as possible. Combining with pre-stretching deformation and cryogenic treatment followed by aging treatment，the tensile strength of the experimental steel reached 3.076 GPa，with the elongation at break of 5.5%，exhibiting excellent strength and plasticity. The analysis and characterization of the microstructures indicated that the lath martensitic microstructure with high dislocation was formed in the experimental steel，and obtained extra fined grains with the average grain diameter of 0.47 μm. TEM and 3DAP results show that a large number of Ni3（Mo，Ti）precipitates is distributed in the matrix，with the average precipitate diameter of 6-7 nm. Precipitation strengthening，grain refinement strengthening and dislocation strengthening are the main strengthening mechanisms，which ensure an ultrahigh strength over 3 GPa of the experimental steel，while the extremely fine submicron grains also ensure the good ductility of the steel.

The current research status of refractory high-entropy alloys（RHEAs） is reviewed，the composition design of RHEAs is described，and the effects of metal elements and non-metal elements on the structure and properties of RHEAs are summarized. In addition，the microstructure and mechanical properties of RHEAs under different preparation methods are described，and the strengthening mechanism of RHEAs matrix composites is discussed. The future development of RHEAs is prospected，and the following suggestions are put forward for its future research direction: enhancing of RHEAs by multiphase synergistic effects through the interface design between different phases；designing and optimizing the composition of RHEAs to develop RHEAs that are easy to process at room temperature；quickly screening the composition and microstructure of RHEAs by combining with high-throughput calculation methods；regulating and controlling the microstructure and structure of RHEAs by additive manufacturing technology；carrying out the configuration design of RHEAs matrix composites to balance the strength and plasticity of RHEAs matrix composites.

With the rapid development of low-temperature fields such as deep space exploration，polar scientific research，low-temperature storage and transportation，the service conditions for low-temperature structural components are becoming increasingly stringent. Therefore，low-temperature materials have gradually become a research hotspot in the world. This article mainly summarizes the low-temperature performance and related mechanisms of common structural materials such as low-temperature steel，aluminum alloy，titanium alloy，aluminum matrix composites and resin matrix composites. The effects of different crystal structures，alloy types，alloying elements and other factors on the mechanical properties of structural materials such as low temperature strength，plasticity and toughness，and the mechanism of low temperature deformation，strengthening and toughening are concluded. The application and prospect of different grades of low-temperature structural materials in different fields at home and abroad are also briefly introduced. The future research prospect of low-temperature materials is put forward.

Propeller propulsion technology plays an important role in aviation field. Composite materials have the characteristics of high specific strength，high specific modulus，high damping，designability and so on. The use of composite material propeller blades can further improve the performance of propeller in terms of mass reduction efficiency，propulsion efficiency，corrosion resistance，noise reduction. Composite material propeller blades have become the general trend. Based on aircraft propeller blades and rotor blades，this paper aims to perform a brief review of the research achievements of aviation composite propeller blades at home and abroad，classifies and expounds the material systems，structural design and molding processes of aviation propellers. The key technical problems and the simulation research on manufacturing process of propeller at home and abroad are summarized. Finally，the future development direction of domestic composite propellers from the aspects of improving the material system，optimizing the structure design，deepening the process research and strengthening the engineering application of numerical simulation technology are concluded.

The room temperature tensile properties and elevated temperature tensile properties of peak aged Al-Cu-Mg-Ag hub forgings after different heat exposure temperatures and heat exposure time were tested，and the thermal stabilities of the forgings at different temperatures were compared and analyzed. The results show that Al-Cu-Mg-Ag forgings exhibit good thermal stability. After exposure at 150 ℃ for 1 to 100 h，there were no significant changes in room temperature tensile properties and elevated temperature tensile properties. Short time heat exposure at 150-200 ℃ for 1 h does not reduce the overall performance，but the strength of Al-Cu-Mg-Ag forgings decreases with the increase of heat exposure temperature and the extension of heat exposure time. After 100 h of exposure at 200 ℃ and 250 ℃，the room temperature yield strength remains 61.1% and 37.2 %，and the room temperature tensile strength remains 77.8% and 60.8%，the elevated temperature yield strength remains 61.6% and 42.8%，and the elevated temperature tensile strength remains 67.5% and 47.6%，respectively. The main precipitates of Al-Cu-Mg-Ag forgings are Ω phase and θ′ phase. Under the experimental conditions of Kt=1 and R=0.1，the room temperature fatigue limit after 200 ℃/10 h heat exposure is 278 MPa，which is 10.6% lower than the fatigue limit of 311 MPa before heat exposure.

Flaw tolerance performance of TC4 alloy was investigated for helicopter transmission systems design. The impact pit flaws and scratch flaws were investigated by fatigue specimens with same flaw depth for flaw tolerance design，and high-cycle fatigue S-N curve tests were conducted. The results show that both scratch flaws and impact pit flaws significantly reduce the fatigue limit of the TC4 titanium alloy. The scratch flaw has a higher flaw influence factor（Kflaw） of 2.29 compared to the impact pit flaw’s Kflaw value of 1.75 under the same flaw depth conditions. Fracture surface analysis provided laws of the fatigue crack initiation and propagation associated with these flaws. Scratch flaws mainly exhibit multiple sources，with crack initiated at the root of the scratch，while the characteristics of fatigue crack initiation for impact pit flaws vary with the applied stress. Multiple sources are observed under high stress lever，with crack initiated on the surface of the pit，while under low stress，the crack initiates at a subsurface of the pit.

Abstract Hills and mountain fields have a high proportion in coastal areas around the world. Especially in China, lots of low-rise buildings are in complex mountain terrain. Compared with the flat topography under typhoons, due to the change caused by complex topography, the damage ratio of low-rise buildings is much larger. This paper investigates the wind pressure distribution in three different configurations of typical mountain terrain on low-rise buildings in coastal areas by wind tunnel tests. At the same time, the results are compared with the wind pressure distribution of low-rise buildings without surrounding structures. The variation of the average pressure coefficient and shape coefficient with the change of hillside height under a wind attack angle of 0° and the trends of average wind pressure coefficients of a low-rise building under wind attack angles of 0° – 90° are studied. The results show that the distribution of pressure in low buildings is significantly affected by the height of the mountain. When the hillside height is half of the scale physical model, the influence coefficient from the mountain to each surface of the whole building is within 50%. When the hillside height is four times that of the model, the influence factor from the mountain to each surface of the whole building is obvious and is most significantly influenced by the leeward roof. The mean design criteria of the low-rise building, such as windward midline, leeward roof, and windward roof in these three typical mountain terrains, should be designed for their higher absolute value of the average pressure coefficient. The mean pressure coefficient under different wind angles and mountain environments has a significant relationship. The most unfavorable wind angle of wind load calculations should be considered when designing low-rise buildings.

Abstract Aerodynamic test rigs are necessary for experimental testing of turbomachines and investigation of possible ways to improve machine performance. Existing installations give higher losses and do not work efficiently at off-design operating modes. An operating part with an adjustable radial diffuser was designed in order to determine the characteristics of turbine annular cascades. Experimental studies and computational verifications showed satisfactory results at various operating modes. The regulated backwall of the radial diffuser ensured supersonic velocity values behind the cascade and overall stable operation in a wide range of Mach numbers up to 1.3 when using compressors of comparatively small capacity. The optimum positions of the regulated backwall were determined, which provided a deep vacuum behind the cascade, as well as 1.5 times Mach number increase compared to the turbine cascade without a diffuser. Changing the inlet channel geometry at supersonic modes leads to an increase in the diffuser efficiency. Additionally, it was determined that the use of the turbine vane cascade in the test rig flow path is not necessary during calculation studies, but instead an axisymmetric vaneless converging area can be applied and give satisfactory results as well as reduce the time spent on calculations. The computational model can be used to optimize the design of an aerodynamic tunnel outlet area.

For advanced aero-engine design and research, modeling and simulation in a digital environment is indispensable, especially for engines of complicated configurations, such as variable cycle engines (VCE) and adaptive cycle engines (ACE). Also, in the research of future smart engines, reliable real-time digital twins are paramount. However, the 2 dominant methods that used in solving the simulation models, Newton-Raphson (N-R) method and volume-based method, are not fully qualified for the study requirements, because neither of them reaches the satisfactory balance of convergence rate and calculating efficiency. In this study, by deeply analyzing the mathematical principle of these 2 methods, a novel modeling and solving method for aero-engine simulation, which integrates the advantages of both N-R and volume-based methods, is established. It has distributed architecture and local quadratic convergence rate. And a novel modeling method for variable area bypass injectors (VABI) is put forward. These facilitate simulation of various configurations of aero-engines. The modeling cases, including a high bypass-ratio (BPR) turbofan and an ACE, illustrate that the novel technique decreases the iterations by about two-thirds comparing with volume-based method, while the success rate of convergence remains over 99%. This proves its superiority in both convergence and calculating efficiency over the conventional ones. This technique can be used in advanced gas turbine engine design and control strategy optimization, and study of digital twins.

The present study investigates the axisymmetric stagnation point radiative flow of a Cu-Al2O3/water hybrid nanofluid over a radially stretched/shrunk disk. In this paper, a new mathematical model has been developed by taking into consideration the concept of different nanoparticles concentration in a hybrid nanofluid, which are Brownian motion and thermophoresis of nanoparticles. A new model for entropy generation has also been provided in the present study. The non-dimensional governing equations of the developed mathematical model are solved using newly developed and efficient overlapping grid spectral collocation method. Numerical stability and residual error test are provided here to show the accuracy of the numerical method in this mathematical model. The outcomes of fluid flow, temperature, and two different types of concentration profiles are depicted, and described in graphical and tabular forms. For the limiting instances, comparison shows excellent agreement among current and results established in the literature. Increasing the strength of magnetic field is seen to increase the radial component of fluid velocity as well as the entropy generated within the system. Two different nanofluid concentration profiles are increasing and decreasing with rising thermophoresis and Brownian motion parameters, respectively, from a particular height above the disk because of the revised nanofluid boundary condition. Temperature profile increases here with increasing Biot number, and increasing Brinkman number causes higher entropy generation number for both stretching and shrinking disks. The enhanced thermal characteristics of the hybrid nanofluid over the single particle nanofluid has been observed.

Turbine blisk is one of the typical components of gas turbine engines. The fatigue life of turbine blisk directly affects the reliability and safety of both turbine blisk and aeroengine whole-body. To monitor the performance degradation of an aeroengine, an efficient deep learning-based modeling method called convolutional-deep neural network (C-DNN) method is proposed by absorbing the advantages of both convolutional neural network (CNN) and deep neural network (DNN), to perform the probabilistic low cycle fatigue (LCF) life prediction of turbine blisk regarding uncertain influencing parameters. In the C-DNN method, the CNN method is used to extract the useful features of LCF life data by adopting two convolutional layers, to ensure the precision of C-DNN modeling. The two close-connected layers in DNN are employed for the regression modeling of aeroengine turbine blisk LCF life, to keep the accuracy of LCF life prediction. Through the probabilistic analysis of turbine blisk and the comparison of methods (ANN, CNN, DNN and C-DNN), it is revealed that the proposed C-DNN method is an effective mean for turbine blisk LCF life prediction and major factors affecting the LCF life were gained, and the method holds high efficiency and accuracy in regression modeling and simulations. This study provides a promising LCF life prediction method for complex structures, which contribute to monitor health status for aeroengines operation.

Variable cycle engine (VCE) is one of the most promising technologies for the next-generation aircraft, the matching of different components in the compression system is a key difficulty VCE faced. To investigate the component matching mechanisms in the VCE compression system, an advanced throughflow program is employed to calculate the characteristic lines of each component, and a zero-dimensional method is developed to capture the component performance deviation during the coupling working process. By setting the compressor stall and choke conditions as the boundary, the operation range of the compression system is first clarified, and the aerodynamic performance in the operation zone is discussed, thus providing a theoretical basis for optimization of the engine operating control scheme. Results show that the efficiency of the core flow is optimum at the left-bottom corner of the operation region, while the total pressure ratio peaks at the right-top area, hence a balance is needed when deciding the matching point. Regulations of component control parameters will change the position of the operation zone, as well as the corresponding aerodynamic performance. Decreasing the core driven fan stage rotating speed can improve the total bypass ratio, yet the total pressure ratio of the core flow will be decreased. Closing the core driven fan stage inlet guide vane can increase the total bypass ratio without changing the core flow aerodynamic performance significantly. The bypass ratio of the compression system can also be increased by increasing the fan stall margin or decreasing its rotating speed, both ways will decrease the total pressure ratio of the core flow. Results of the study will benefit the variable cycle engine design process in operation point evaluation and thermodynamic cycle optimization.

In this study, we have analyzed fluid mobility and thermal transport of the SiO2/kerosene nanofluid within two rotating stretchable disks. The top disk is simulated to be oscillating with a periodic velocity and squeezing continuously the nanofluid within a porous medium and making the fluid to flow perpendicularly to the situated magnetic field. Thermal radiation effects are considered in the heat transfer model. The non-linear (NL) PDEs that describe the nanofluid mobility structure and thermal transport are transformed into system of NL-ODEs by introducing adequately suitable non-dimensional variables after which the NL-ODEs were numerically solved via spectral quasi-linearization method (SQLM) on overlapping grids. The consequences of several pertinent parameters of the model on pressure, temperature, velocity, skin drag coefficient and thermal transport rate are examined and elucidated in detail with the aid of figures and tables. It was found that the flow structure with prescribing conditions develops negative pressure situation which has vast applications in modern day medical engineering, especially in the construction of air pressure stabilizers used in medical isolation and wound therapy physiology.

This paper presents the results of studying the surface properties changes of a thermoregulating coating based on polystyrene and silica filler after proton irradiation with an energy of 50 keV at a fluence of 3 × 1015 cm−2. After proton irradiation, the values of the contact angle of wetting with water increase by 3.5% and 14.9% for polystyrene and the coating, respectively. The free surface energy (energy of the surface layer) of polystyrene and the coatings before and after proton irradiation was calculated using the Owens-Wendt-Rabel-Kaelble method. There was a significant increase in the polarity of the polystyrene surface (γp increased by a factor of 2.2) after proton irradiation. For the coating, an increase in γp by a factor of 3.89 was observed after proton irradiation. Structural changes in the coating were presented by IR Fourier spectroscopy. A slight decrease in the absorption intensity of all characteristic bands compared to the unirradiated sample was noted. It was found that the irradiation of the coating with protons led to the formation of macromolecules with hydroxyl, carbonyl, and carboxyl bonds, as well as the formation of dimeric and oligomeric siloxane chains. It was also found that after irradiation of a pure polystyrene sample with protons, the value of the solar absorption αs increased by only 4.2%; whereas for the coating with silica filler, the value of αs increased by 28.6%.

As the transport sector is responsible for the consumption of a vast proportion of the oil produced, it is mandatory to research feasible solutions to tackle this issue. The application of aerodynamic attachments for passive flow control and reducing resisting aerodynamic forces such as drag and lift is one of the most practicable ways to minimize vehicle energy consumption. The flaps are one of the most innovative aerodynamic attachments that can enhance the flow motion in the boundary layer at the trailing edge of the wings. In the present paper, the flap is designed and modeled for controlling the airflow at the roof-end of a 2D Ahmed body model, inspired by the schematic of the flap at the trailing edge of the wing. As a result, the flap's geometry and position from the roof-end of the car model are parameterized, which leads to having four design variables. The objective functions of the present study are the vehicle's drag coefficient and lift coefficient. 25 Design of Experiment (DOE) points are considered enabling the Box-Behnken method. Then, each DOE point is modeled in the computational domain, and the flow-field around the model is simulated using Ansys Fluent software. The results obtained for the DOE points are employed by different regressors, and the relation between design variables and objective functions is extracted using GMDH-ANN. The GMDH-ANN is then coupled with three types of optimization algorithms, among which the Genetic algorithm proves to have the most ideal coupling process for optimization. Finally, after analyzing the variations in the geometry and position of the roof flap from the car roof-end, the roof-flap with specifications of L = 0.1726 m, α = 5.0875°, H = 0.0188 m, and d = 0.241 m can optimize the car drag and lift coefficients by 21.27% and 19.91%, respectively. The present research discusses the opportunities and challenges of optimal design roof-flap geometry and its influence on car aerodynamic performance.

The interaction of cowl shock wave and boundary layer has a crucial effect on the stability, operability and performance of hypersonic inlets. Many studies on inhibiting the separation and managing the strength of the interaction of the shock wave and boundary layer with expansion corner have been conducted. However, the expansion waves near the circular arc shoulder to effectively control the interaction and cowl shock arrangement is little investigated. Therefore, the interaction of the cowl shock wave and boundary layer under the fluence of the expansion waves is studied by inviscid and viscous numerical simulations. The results reveal that the expansion waves have an important impact on the interaction between the cowl shock wave and boundary layer and the strength of shock wave, and that there are four types of interaction processes with the change of the relative impingement positions of cowl shock wave. The expansion waves have a different influence on the shock wave and boundary layer interaction at different incident points. When the incident point of the cowl shock wave goes far downstream from the end of the circular arc shoulder, the influence of expansion waves is weakened, and the magnitude of separation zone increases. However, when the expansion waves are applied to the interaction of the cowl shock wave and boundary layer on the circular arc shoulder, the separation can be effectively controlled. In particular, while the expansion waves interact with the shock wave and boundary layer in the back half of the circular arc shoulder, the separation is best inhibited. Compared with the upstream and downstream incident points, the scale of separation area in the optimal control region is reduced by 65.3% at most. Furthermore, the total pressure recovery coefficient first increases and then decreases when the cowl moves from upstream to downstream, and the total pressure recovery coefficient reaches the maximum value of 68.36% at the incident position of cowl shock wave d = 8.09δ0.

The melting phenomenon plays a critical role in optimizing the performance of power storage, electronic cooling, and semiconductor devices. The present study aims to analyze the melting effect on the flow of Carreau fluid over a stretchable cylinder, with special consideration given to the impact of quadratic thermal radiation. Similarity variables and the homotopy analysis method are used to simplify and determine the semi-analytical homotopic solutions of the governing equations. The present findings reveal that the melting parameter increases the heat transfer rate by more than 10% for both fluids, water (Pr = 0.71), and polymer (Pr = 10). However, as the temperature ratio due to quadratic radiation increases, the local Nusselt number for water has been reduced by 25%, and an even more substantial reduction is observed for the polymer. The present study offers valuable insights into achieving optimal efficiency in electronic devices.

This article presents a case study on estimating the real service inspection intervals for German-brand passenger cars in Kazakhstan and Poland. This study aimed to identify disparities between the official recommendations of manufacturers for car maintenance and the real data collected in these two countries. The following passenger cars were examined: Audi A6, Q5, and Q8; Porsche Cayenne and Cayenne coupe; and Volkswagen Passat, Polo, Teramont, Tiguan, Touareg, Arteon, Golf, T-Cross, Tiguan all space, Touran, T-Roc, and Up. To assess the difference between real and recommended values, the manufacturer criteria of a recommended mileage of 15,000 and 30,000 km or a time frame of 365 and 730 days to the first service inspection were applied. The data analysis showed that in Kazakhstan, 31.4% of cars did not meet the warranty conditions, while in Poland, it was 21.0%. The dominant criterion that was not met was the time criterion. The assessment of these factors emphasizes the importance of customizing vehicle maintenance schedules to the specific conditions and driving behaviors prevalent in each country. The practical contribution of the article lies in uncovering the discrepancies between official manufacturer recommendations for car maintenance and the actual data collected in Kazakhstan and Poland. By identifying specific models, Volkswagen Touareg and Tiguan in Kazakhstan and Volkswagen Up in Poland, for which the maintenance intervals deviated significantly from those recommended, this study offers valuable insights for optimizing service schedules and improving the efficiency of maintenance practices in these countries. From a scientific perspective, this article contributes by providing empirical evidence of real-world maintenance behaviors for German-brand passenger cars.

The performance of an electric vehicle (EV) notably depends on an energy management controller. This study developed several energy management controllers (EMCs) to optimize the efficiency of EVs in real-time driving conditions. Also, this study employed an innovative methodology to create EMCs, efficiency maps, and real-time driving cycles under actual driving conditions. The various EMCs such as PID, intelligent, hybrid, and supervisory controllers are designed using MATLAB/Simulink and examined under real-time conditions. In this instance, a mathematical model of an EV with a switched reluctance (SR) motor is developed to optimize energy consumption using different energy management controllers. Further, an inventive experimental approach is employed to generate efficiency maps for the SR motor and above-mentioned controllers. Then, the generated efficiency maps are integrated into a model-in-loop (MIL)-based EV test platform to analyze the performance under real-time conditions. Additionally, to verify EV model, a real-time driving cycle (DC) has been developed, encompassing various road conditions such as highway, urban, and rural. Subsequently, the developed models are included into an MIL-based EV test platform to optimize the performance of the electric motor and battery consumption in real-time conditions. The results indicate that the proposed supervisory controller (59.1%) has a lower EOT SOC drop compared to the PID (3.6%), intelligent (21.5%), and hybrid (44.9%) controllers. Also, the suggested controller achieves minimal energy consumption (44.67 Wh/km) and enhances energy recovery (−58.28 Wh) under different real-time conditions. Therefore, it will enhance the driving range and battery discharge characteristics of EVs across various real-time driving conditions.

Curb detection tasks play a crucial role in the perception of the autonomous driving environment for logistics vehicles. With the popularity of multi-modal sensors under the BEV (Bird’s Eye View) paradigm, curb detection tasks are increasingly being integrated into multi-task perception networks, achieving robust detection results. This paper modifies and integrates the tri-plane spatial feature representation method of the EG3D network from the field of 3D reconstruction into a BEV-based multi-modal sensor detection network, including LiDAR, pinhole cameras, and fisheye cameras. The system collects a total of 24,350 frames of data under real road conditions for experimentation, proving the effectiveness of the proposed method.

Variable flux reluctance machines (VFRMs) are increasingly attracting research interest due to their magnetless and robust brushless structure. Under the modulation effect of the airgap permeance, the VFRM operates with a series of field harmonics, distinguishing it from conventional AC synchronous machines. This paper deals with the analysis and preliminary design of the VFRM from the perspective of multiple working airgap field harmonics. Firstly, the spatial and temporal order of the working field harmonics are defined. The systematic winding theory, including the unified star of slots and winding factor calculation method, is established to consider all these working harmonics. Then, an average torque model is built and simplified. The key role of 1st-order rotor permeance, 1st- and 3rd-order polarized stator permeance is deduced. The relationship between key parameters and average torque is computed, providing a guideline for the preliminary design of the VFRM.