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Path planning for taxi of carrier aircraft launching

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science China(Technological sciences) 2013年第6期56卷 1561-1570页

作者： WU Yu QU XiangJu school of aeronautic science and engineering Beihang University

Launching efficiency is an important index to measure the fighting capacity of an aircraft carrier. The study on path planning for taxi of carrier aircraft is of great significance for enhancing the launching efficiency. Considering the launching efficiency and the safety in operation of carrier aircraft launching and taking into account the carrier aircraft maneuver performance, deck environment and feature of mission, we proposed a conceptual model which contains the key elements of path planning for taxi of carrier aircraft. Subsequently, the objective function for the path planning problem and its mathematical model containing various constraints were established. With the A * search algorithm, a dynamic weight heuristic function was designed. According to the characteristic of path planning model for taxi of carrier aircraft, a simple and effective detection method was introduced. Finally, a feasible path for taxi of carrier aircraft, which meets the constraints, was presented. Taking the Nimitz-class aircraft carrier as an example, the paths for taxi of carrier aircraft launching from elevators to catapults were planned. Simulation results demonstrated the rationality of the model and the effectiveness of the algorithm.

关键词： carrier aircraft carrier path planning aircraft taxi carrier aircraft launching

Flutter Analysis of Aircraft Wing Using Equivalent-Plate Models with Orthogonal Polynomials

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Transactions of Nanjing university of aeronautics and Astronautics 2015年第5期32卷 508-516页

作者：唐健谢长川杨超 school of aeronautic science and engineering Beihang University

A method of equivalent simplification,using equivalent-plate models(EPMs),is *** is to achieve goals of rapid modeling and effective analysis in structural dynamics and flutter analysis of complex wing *** is on the assumption that the wing structures discussed are composed of skin,beams and ribs,and the different plate units(such as skin,beam web,rib web)are not distinguished in modeling,which is to avoid the complex pre-processing and make it more *** the effect of transverse shear deformation into consideration,the equivalence is based on the first-order shear deformation theory,and it can import the model files of MSC/NASTRAN and process the information to accomplish the equivalent *** Ritz method is applied with the Legendre polynomials,which is used to define the geometry,structure and displacements of the ***,the selection of Legendre polynomials as trial functions brings good accuracy to the modeling and can avoid the *** is in contrast to the EPM method based on the classical plate *** vibration and flutter analysis,the results obtained by using EPM agree well with those obtained by the finite element method,which indicates the accuracy and effectiveness in vibration and flutter analysis of the EPM method.

关键词： equivalent-plate model(EPM) flutter analysis vibration analysis Ritz method orthogonal polynomials

Efficient Security Sequencing Problem over Insecure Channel Based on Homomorphic Encryption

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China Communications 2016年第9期13卷 195-202页

作者： Mingxu Yi Lifeng Wang Yunpeng Ma school of aeronautic science and engineering Beihang University

In the field of sequencing of secret number,an important problem is how to establish an efficient and secure protocol for sorting the secret *** a powerful tool in solving privacy sequencing problems,secure multipart computation is more and more popular in anonymous voting and online *** the present study,related secure computation protocol for sequencing problem is not many by *** order to improve the efficiency and safety,we propose a security sequencing protocol based on homomorphic *** also give analysis of correctness and security to highlight its feasibility.

关键词： homomorphic encryption privacy sequencing problem secure multipart compu- tation information transformation

A high-efficiency aerothermoelastic analysis method

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science China(Physics,Mechanics & Astronomy) 2014年第6期57卷 1111-1118页

作者： WAN ZhiQiang WANG YaoKun LIU YunZhen YANG Chao school of aeronautic science and engineering Beihang University

In this paper,a high-efficiency aerothermoelastic analysis method based on unified hypersonic lifting surface theory is *** method adopts a two-way coupling form that couples the structure,aerodynamic force,and aerodynamic thermo and heat *** aerodynamic force is first calculated based on unified hypersonic lifting surface theory,and then the Eckert reference temperature method is used to solve the temperature field,where the transient heat conduction is solved using Fourier’s law,and the modal method is used for the aeroelastic ***,flutter is analyzed based on the p-k *** aerothermoelastic behavior of a typical hypersonic low-aspect ratio wing is then analyzed,and the results indicate the following:(1)the combined effects of the aerodynamic load and thermal load both deform the wing,which would increase if the flexibility,size,and flight time of the hypersonic aircraft increase;(2)the effect of heat accumulation should be noted,and therefore,the trajectory parameters should be considered in the design of hypersonic flight vehicles to avoid hazardous conditions,such as flutter.

关键词： aerothermoelastic two-way coupling unified hypersonic lifting surface theory piston theory flutter

Feasibility analysis of high excess pressure cockpit using material substitution based on strain energy

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science China(Technological sciences) 2014年第3期57卷 598-606页

作者： GAO HaiPeng LIU Meng WANG Jun school of aeronautic science and engineering Beihang University

The design concept of high excess pressure cockpit has been proposed as a solution to solve the ergonomics problems caused by cockpit *** address the contradiction among mass,economy,maneuverability and environment ergonomics,considering the composite advantages of high strength and lightweight,the feasibility analysis concept of high excess pressure cockpit based on material substitution is proposed in the *** on the strain energy analysis on finite element model,the iteration design method of equal stiffness and lightening effect analysis on material substitution are presented,The weight reduction effect after material substitution can be evaluated intuitively by using equal stiffness *** calculation result of cockpit indicates that the lightening effect can reach 35.09%.Because of the complexity of cockpit design,bi-level optimization method is proposed and performed by means of the First-Order Radio *** research shows that the method can achieve good *** feasibility of high excess pressure cockpit is studied from the aspect of the relationship between excess pressure and mass,and the research demonstrates that,due to the utilization of T300/4211 in place of 6061 alloy,the excess pressure of cockpit increases from 35 to 45 kPa,a 28.57%increase,while the cockpit mass is decreased by 12.56%.Thus,the contradiction among mass,economy and environment ergonomics can be coordinated,which can provide a reference for the design of high excess pressure cockpit.

关键词： high excess pressure cockpit material substitution strain energy environmental ergonomics cockpit mass

Numerical simulation of aerodynamic interactions among helicopter rotor,fuselage,engine and body of revolution

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science China(Technological sciences) 2014年第6期57卷 1206-1218页

作者： CAO YiHua WU ZhenLong HUANG JunSen school of aeronautic science and engineering Beihang University

Numerical simulations of helicopter aerodynamic interactions among the main rotor,fuselage,engine inlets/outlets and slung loads of specific geometries have been conducted by very few *** this work,the steady-state compressible Reynolds-averaged navier-stokes equations are solved to study the aerodynamic interactions among helicopter rotor,fuselage,engine and body of revolution in three cases,namely MI-171V5,ROBIN and *** the first case,the downwash flow provided by the rotor of the uniform actuator disc model induces a significant deflection of the airflow *** vortex-shaped distribution and evolution are discussed in *** engine can effectively change the overall flow *** asymmetry of the flow field is observed by using the non-uniform actuator disc *** analysis of ROBIN and quantitative computation of UH-60A show a consistent accuracy of the rotating reference frame model for *** blade tip vortex motion of UH-60A is simulated and its radial position prediction is compared to empirical *** performing flow of UH-60A in hover,both the fuselage normal force and rotor lift decrease because of the impact of the body of revolution.

关键词： numerical simulation aerodynamic interaction helicopter actuator disc model rotating reference frame model

A review of bird-like flapping wing with high aspect ratio

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Chinese Journal of aeronautics 2023年第1期36卷 22-44页

作者： Changchuan XIE Nongyue GAO Yang MENG Yue WU Chao YANG school of aeronautic science and engineering Beihang UniversityBeijing 100191China

Bird-like flapping-wing vehicles with a high aspect ratio have the potential to fulfill missions given to micro air vehicles,such as high-altitude reconnaissance,surveillance,rescue,and bird group guidance,due to their good loading and long endurance *** and aeronautical researchers have explored the mystery of avian flight and made efforts to reproduce flapping flight in bioinspired aircraft for ***,the cognitive depth from theory to practice is still very *** mechanism of generating sufficient lift and thrust during avian flight is still not fully *** wings with unique biological structures such as feathers make modeling,simulation,experimentation,and analysis much more *** paper reviews the research progress on bird-like flapping wings from flight mechanisms to *** used numerical computing methods are briefly *** aeroelastic problems are also *** results of the investigation show that a leading-edge vortex can be found during avian *** induction and maintenance may have a close relationship with wing configuration,kinematics and *** present models of flapping wings are mainly two-dimensional airfoils or three-dimensional single root-jointed geometric plates,which still exhibit large differences from real bird *** is encouraged to consider the nonignorable effect on aerodynamic performance due to large-scale nonlinear *** appropriate flexibility can improve the peak values and efficiencies of lift and thrust,but the detailed conclusions always have strong background dependence.

关键词： Aeroelasticity Bird-like flapping wing Flapping motion High aspect ratio Modeling Nonlinear

Analysis of Reflection Characteristics for Foam Filled Grid Structure

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Journal of Wuhan university of Technology(Materials science) 2013年第1期28卷 1-5页

作者：徐元铭徐胜 school of aeronautic science and engineering Beihang University

The reflection characteristics of gird structures are calculated by the spatial network method in the case of normal incidence plane electromagnetic wave. The numerical result shows that the grid panels without electromagnetic wave absorbing foams are not ideal. However, the absorbing ability can be achieved as low as -25 dBsm from 8 GHz to 12 GHz when the grid cells are filled with foam absorbers. Also it is noted from computation that the foam filled grid structures with larger cell size, higher and thinner ribs will improve the absorbing abilities, which illustrates that they can be used as the effective light-weight stealth structures for aeronautical application.

关键词： grid structure spatial network method (SNM) foam reflection characteristics

Detail fatigue rating method based on bimodal Weibull distribution for DED Ti-6.5Al-2Zr-1Mo-1V titanium alloy

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Chinese Journal of aeronautics 2022年第4期35卷 281-291页

作者： Tianshuai WANG Xiaofan HE Jinyu WANG Yuhai LI school of aeronautic science and engineering Beihang UniversityBeijing 100083China

Previous studies have shown that the fatigue life distribution of metal materials fabricated with Additive Manufacturing(AM) methods, such as Direct Energy Deposited(DED) Ti-6.5Al-2Zr-1Mo-1V alloys, exhibits two peaks. To promote the application of AM in aerospace and other engineering fields, developing a fatigue strength evaluation method suitable for AM materials based on their unique fatigue behaviours and fatigue life distributions is necessary. In this paper, a novel Detail Fatigue Rating(DFR) method was developed to evaluate the fatigue strength of DED Ti-6.5Al-2Zr-1Mo-1V based on a bimodal Weibull distribution and the excessive restriction on the allowable stress of potential was improved. Meanwhile, a Bimodal Weibull distribution model for fatigue life and its parameter estimation method were established based on a twoparameter Weibull distribution. The fatigue life at a specific reliability level and confidence level was calculated by using the bootstrap method. The calculation results showed that fatigue life estimated by using the bimodal Weibull distribution at the high reliability level and high confidence level is higher than that estimated by using the two-parameter Weibull distribution. Furthermore,The S-N curve at the specified confidence level and reliability level was fitted.

关键词： Bimodal weibull distribution Detail fatigue rating method Directed energy deposition Distribution parameter estimation Fatigue reliability