Abstract:Numerical simulation methods, impact factor and fuel tank structure design are the main research content for analyzing the effect of Hydrodynamic Ram to aircraft fuel tank. The development of latest research methods and achievements show that the materials of projectile, velocity and air proportions were the influence factor of Hydrodynamic Ram. The results provide a reference for the deeply researching of hydrodynamic ram。

Abstract:Sharing airspace with manned aircrafts in different degree of cooperation is the future trend of unmanned aerial vehicle (UAV) operations, and collision avoidance issues become key challenges hindering UAV from flying beyond segregated airspace. Requirements of autonomous collision avoidance for UAV are analyzed from the perspective of the particularity of the UAV collision avoidance combined with current layered aircraft collision avoidance strategies, and framework of UAV autonomous collision avoidance system is proposed. Two key techniques and their application scope and main issues of UAV autonomous collision avoidance are analyzed and discussed inductively, i.e. sensor technologies and collision avoidance algorithms, and on this basis manage system of UAV autonomous avoidance is proposed. Finally, development trends of UAV autonomous collision avoidance techniques are explored.

Abstract:The aerodynamic interference among rotors has strong affect on the lift force of the quadrotor UAV, it is necessary to study on the interference to provide a reference for the aerodynamic layout design. An equivalent actuator disk model of airplane propeller is presented, which takes into consideration such factors as such as diameter, chord,pitch and rotating speed of rotor, etc. The effectiveness of the equivalent actuator disk is established thorough increasing momentum source,calculating the different lift force of a single rotor in hover on Fluent and comparing with the experimental data. Thorough the above method, the effects of interference among rotors on lift force of quadrotor in hover is calculated that have different rotor distances. The resulted of the calculation indicates that the smaller rotor distance causes the stronger interference as well as the more loss of lift force.

Abstract:In order to simulate the initial process of airborne more truly, this paper is first to present the simulation methods of stable parachutes in airborne wind tunnel tests in China, including figuring out the similar parameters and simulating the drag coefficient. It mainly discusses a method to measure drag coefficient by fastening counterweights onto the extremity of parachute and doing the free fall tests. It is demonstrated that the method can accurately measure the drag coefficient, and opening holes on the top of the stable parachute can effectively adjust the drag coefficient and make the falling of stable parachutes steadier. The wind tunnel tests results agree with the complex flow field characteristic near the fuselage, and are in line with the airborne trajectories law on video. It shows that the simulation technology of stable parachutes is feasible.

Abstract:A combined probabilistic analysis method on structural durability and damage tolerance is presented for multiple site damage-prone structure to analyze the flight structure service life and reliability in the same time. The probabilistic fracture mechanics method is used in the durability analysis. A series reliability model is presented to get a conservative estimation of economic service life under given reliability requirement. Monte-Carlo simulations are conducted in conjunction with a three-parameter lognormal probability distribution for the residual life of a structure. The reliability of the structure under different crack propagation life is obtained through life interference model. The feasibility of the method is validated with a numerical example of a collinear porous plate.

Abstract:Hardware-in-the-loop simulation is an important stage of the engine fault diagnosis algorithm shift from theory to practical engineering applications, but the study most remain in the software simulation stage. A hardware-in-the-loop simulation platform of civil turbofan engine health diagnostic was constructed. The multiple schedule piecewise linear model with health parameters and faults simulation method in hardware platform were developed. The health diagnostic algorithm was used to the simulation. The results show that the platform and the use of models and methods are effective, and have some engineering application value.

Abstract:The tip-jet driven system is a promising power driven device. This paper is aimed at designing and studying for tip-jet driven system .It establishes a driven system experimental platform based on centrifugal compressor, obtains the interior-flow parameters of the pipe and static thrust of the spout by changing the inlet conditions, and then calculates the output power of this driven system to analyze the characteristic of the system. Further the CFD numerical simulation method is used to simulating various experimental conditions. The results show that the simulation data are consistent with that of experiment , the force and power are bigger when the total pressure changes higher, and provide references for CFD numerical simulation technology used in calculating the efficiency of tip-jet driven system and selecting source of the power.

Abstract:In order to study on cycle design projects with different cycle parameters of turboshaft engine, the engine/components integration design model which includes performance calculation, gas-flow-path size estimation, preliminary aerodynamic design of components and weight estimation is set up. The engine/components coupling design method which combines the engine/components integration design model, coupling design maps of components efficiencies and aerodynamic loadings and turbine cooling flow estimation model is set up. The results show that firstly, low pressure ratio design project, high turbine inlet temperature design project and combined design project with low pressure ratio and high turbine inlet temperature have their own advantages in actual technology level. Secondly, high cycle design projects base on the advancement of technology level. Finally, the engine integration design directions of advanced turboshaft engine will develop towards high cycle design projects and low cycle design projects in the future.

Abstract:To study the high stress volume effect on the low cycle fatigue damage of disk, and improve the precision in the life of disk, considering the deficiency of precision in forecasting the medium and long life of disks by the volume method based on the strain life a volume method based on the SWT model for analysis of the probability life of disk was proposed. The method is based on the SWT model which regards the maximum principal strain plane as critical plane, combining with the volume method in which the size effect were considered, and it is unnecessary to consider the correction of mean stress. Then the fatigue probability life of a fan disk was analyzed using the method given. The computational median life fits well with the experimental one, precision of forecasting is higher than the result by the point method based on the strain life and the method of stress correction coefficient. It is shown that volume method based on the SWT model can be used to estimate the medium and long probability life of aero-engine fan disks.

Abstract:In flight test, the measuring environment is very complexity. If the flight test data is unprocessed and directly used for the identification of aerodynamic derivatives, it will reduce the accuracy of the identification and even can result in iteration divergence or convergence to the error value. The paper puts forward a set of method, which contains identification and correction of data outliers, smoothing, filtering, time delay correcting, and compatibility checking, and the proposed flight test data processing method on the aerodynamic derivative identification accuracy effectively is verified by the flight test data.

Abstract:The Lift Fan UAV in flying wing configuration not only has the advantages of the flying wing, but also can be capable of short distance/ vertical takeoff and landing(S/VTOL). To study its aerodynamic performance is the foundation for building the dynamic of flight. In this paper, the Lift Fan UAV’ aerodynamic was studied in transition stage, and analyzed lift, drag and moment with changes of the velocity and angle of attack. Aiming at the special velocity, the reason was explained by the streamline. In addition, some method to release the fluid separation was put forward. According to the result, it can be seen that the lift, drag, and up nose moment increase with the increasing of velocity. At the same velocity, by the angle of attack going up, the lift is going up and the outer wing is the main source to get the lift. The drag decrease first and increase finally. In comparison with the normal steady flight, the up nose moment is much higher. Besides, these two medications to improve the fluid separation are simple and effective.

Abstract:Aimed at force fighting phenomenon in action-action force combination configured of the certain aircraft control surface drive system，the resolution with cross-channel force equilibrium methodology was exploited, according to project，the mitigation effect of the methodology under different discrepant signals influence was simulated in AMESim software，the simulation result of reveals correctness dang effectiveness of the equilibrium methodology， the simulation result reveals that the resolution not only mitigates force fight in parallel drive system effectually，but also was the optimal force fight mitigation plan。

Abstract:Based on laser tracker development, the development of a scalable laser tracker devices -- intelligent scanner I-Scan，but for its calibration, there was no related national standards and enterprise standards can be based on. Compared the results of I-Scan scan plane gauge block of standards and standards ball rules with measurements of high precision coordinate measuring instrument, and meet intelligent scanner accuracy and positioning accuracy requirements. Finally, the intelligent scanner I-Scan the uncertainty of measurement was analyzed, and solved the intelligent scanner calibration and evaluation, the intelligent scanner calibration and evaluation has a certain reference value.

Abstract:The spring analogy method, based on the physical model, and the radial basis functions (RBFs) interpolation method, based on the algebraic method are two typical and common unstructured grid deformation methods to achieve the computing grid deformed with the moved boundary in unsteady flow simulation. In this paper, a detailed quantitative study is conducted on the deformation characteristics of the two methods. First of all, the pitching of NACA0012 airfoil is taken as an example to compare the CPU time and the maximum deformation capacity of the two methods. Furthermore, the mesh quality and cell quality contours under typical pitch angles change with pitching angles and time steps are also studied. A standard flow solver result is proposed as well. The above results show that the RBFs method is remarked with higher numerical efficiency, stronger adapting ability for large mesh deformation and higher stability for mesh quality comparing with the spring analogy method .

Abstract:Using the dynamic nested grid and the CFD method to simulate the separation trajectory. To predict the trajectory of the object from the airplane, a numerical simulation program based on the POD method was established. Using the CFD simulation trajectory as samples, changing the flight Mach number and the angle of attack as an example, introduced the implementation steps of the POD method to predict the trajectory from the airplane. Results from the numerical example, based on the existing sample data,the POD method relative to the CFD method can greatly reduce the computation time, and the results obtained by the POD predicted good with the results from CFD method, provides a quick easy prediction for the separation trajectory in engineering applications.

Abstract:Urged by the development of civil aviation industry and the huge market demand, the research and manufacture of regional aircraft has been put on the agenda . This paper illustrates the process to design the integral panel of horizontal stabilizer. The primary design is made to meet the requirements of general layout, airworthiness, weight ,strength, stiffness, etc .The panel structural array of horizontal stabilizer is choosed . The basic physical dimensions are confirmed by using formula and engineering experience. The satisfied dimensions are educed after many intensity checking and iteration .The detail design is calculated according to the fatigue, damage tolerance, craft, fasteners connecting and prevention of corrosion. The design of the panel can meet many requirements and the weight is as light as possible. This paper can be a reference to the similar structural design.

Abstract:The continuous effects of aircraft operational environment spectrum will cause corrosion damage to aircraft structures, which is difficult to detect or test in outside field. Based on the material’s S-N statistics and supposing the pitting-corrosion damage as the initial defect, this paper establishes a model to calculate the fatigue life of pitting-corrosion damage by combining the damage mechanics with the finite element method, and proposes an improved damage parameters determining method. By comparing the simulation results of pitting-corrosion damage with the test results, the model is proved to validated, accuracy and feasible in assessing metallic pitting-corrosion damage and can be represented as references for further study in corrosion fatigue.

Abstract:Simplified modeling of the landing gear system can reduce the difficulty of the landing dynamic response, which offers theoretical foundation and reference for the preliminary design of landing gear. Based on the viscoelastic rods technique, the simplified modeling method of diagonal stanchion landing gear system is studied and used to analyze the landing dynamic response with ANSYS/LS-DYNA software. First, based on the landing gear structure and landing status, the simplified dynamics analysis model of the diagonal stanchion landing gear system is established by using the viscoelastic rods technique. The numerical solver program of the differential equations is compiled by MATLAB. By comparing the load curves, the displacement curves and the energy absorb chart, it is shown that the modeling method based on the viscoelastic rods can better simulate the landing dynamic response. The suggested method is valuable for the landing gear preliminary design and the detailed design of connection structures.

Abstract:According to the multiple phases during the ground manoeuvres, different loading cases were analyzed and the relevant breakdown models as well as the derivation method for the landing gear loading spectrum were provided. In order to do research on the typical structure of nose undercarriage and the general loading actions, the load model and the mathematic model were built based on the general nose landing gear structure. Critical load case picked from the loading spectrum was studied and real reasonable aircraft structure parameters were introduced in the calculation. The results indicate the method of combining the loading spectrum and the mathematic model to obtain the main joint loads was feasible which could be the support for the later fatigue life estimation. This paper provides the methods and theoretical support for loading spectrum development and the loading analysis of undercarriages.

Abstract:When the civil aircraft fall into the area of stall angle of attacks,air force will show hysteresis,steep drop and other strong nonlinear characteristics,and the track becomes unstable. To solve the problem,bifurcation analysis method is applied to analyze the control characteristics of aircraft near stall region, and its oscillation region, multi-equilibrium points are obtained.Based on the nonlinear optimal control theory,aircraft stall recovery at high angle of attack is designed. With the Galerkin algorithm, the suboptimal controller parameters are claculated,and the simulation of the aircraft falling into stall and recovery when descending is verified.The results show that the controller can be well controlled to recovery from the stall and resume normal track.

Abstract:The state-of-art of Five Qualities (Reliability, Maintainability, Testability, Safety and Supportability) home and abroad is compared, and the Five Qualities Integration design characteristics and engineering application problems such as data, activities and tools integration etc are summarized. On the basis of that, Five Qualities Integration design program and design requirements during aircraft development is studied. Five Qualities integration environment is Preliminary built, including environment building rules, environment schedule and the required key techniques, all of which are described in detail.

Abstract:The method to satisfied the high requirement of aviation to aero assembly time and quality is setting up movable type production line. Combine Q400 joining mobile production line,we make an in-depth study to work principle and distinguishing feature of air cushion floating device. In this article description and design of mobile jig structure is stressed, and finite element analysis and detailed calculation or analysis to the main technical parameters of cushion device as:layout,quantity,driving force and so on is also included in. The application of cushion suspension device to mobile type production line satisfy the aeroplane assembly requirement of high quality and high efficiency. Research results could be used as reference for other aerocraft mobile production line.