Abstract:According to the folding wing morphing aircraft, designed a planetary gear train of folding mechanism, which suit assembly in the small space of morphing aircraft. On the basis of the systematic study of the planetary gear design goals, variables and constraints, describes the floating-point coded genetic algorithm, using the MATLAB optimization toolbox to optimize its main parameters. Research shows that the structure weight loss 16.7% compared with the safety coefficient method, achieve the minimum weight of the folding mechanism in the case of meeting the design specifications. Therefore the floating-point coded genetic algorithm optimization solution for planetary gear mechanism design is an effective optimal design method.

Abstract:For studying combustor-isolator matching of dual-mode Scramjet and analyzing the performance requirement of isolator in different mode, based on lumped parameter equations for performance computation of scramjet put forward by our team, critical energy method was put forward for computation of mass flow balance between isolator and combustor, the computation model of Scramjet was built, and the corresponding computer program was developed, the dual-mode Scramjet performance and mass flow balance in different mode were computed and analyzed, one dimension flow parameters of isolator and combustor were gained and study in different mode, and the isolator performance requirement of Scramjet were found. The maximum fuel mass flow and isolator separate length near choking margin was computed when flight Mach number Ma₀=4.0~7.0. It was shown from the computation results that: critical energy method was correct and effective and it could be used for computation of mass flow balance between isolator and combustor, the isolator separating length is much longer when the Scramjet operates in choking mode at high flight Mach number, and it should be took into basic consideration for engineering design.

Abstract:Based on the geometric boundary conditions of central line of the S-shaped intake, a polynomial construction method was put forward in order to extend the selection of central line. Depending on the different position of inflection point, 9 typical central lines were given, and the respective S-shaped intake geometric models were built up. The total pressure recovery, outlet dynamic pressure and index were calculated by solving the 3-D Navier-Stokes equations，and concluded the relationships between the position of S-shaped intake central line inflection point and the performance parameters.

Abstract:In order to test the high applicability of HS990 Piston Aero-Engine, use different carburetors experiments on HS990 engine in an altitude simulation test cell. Test results demonstrated that the maximum operating height of HS990 piston engine exceeds 7km. An auxiliary electric fuel feeding assembly should be employed while the engine operating with a non-pressurized fuel tank above 5km. When the altitude is above 5km and the inlet temperature is below -18℃, the existing diaphragm carburetor will reduce or even stop fuel supplying, which finally caused the engine flameout. Comparing with the imported carburetor, HS990 piston engine adopting homemade carburetor has a better power- altitude performance, but less operating stability in high altitude. Appropriate cooling air flow will advantage the cylinder to decrease its operating temperature at high altitude. But excessive cooling air flow will cause the engine operating instability due to the lower temperature of cylinder.

Abstract:Based on the continuum damage mechanics theory and Gibbs free energy principle, a two dimensional progressive damage model is built to describe the damage and failure process of composite laminates under the plane stress state. This damage mode is combined with the Hashin damage criterion and coded by the ABAQUS user subroutine as a new damage constitutive model for composite laminates. To verify its capacity, a FE model with above damage constitutive is applied to analyze the damage onset and propagation of the composite laminates with centric cutout and compared with the experimental, and the comparable results shows the above damage constitutive has relative high capability in describing the laminates structural damage propagation processes. This material model is further used to study damage evolution in different layers for laminates with three different cutout-shapes under the shear load, and the results shows the cutout-shape has very sensitive influence in damage and failure processes of composite laminates.

Abstract:Cylindrical shell plays an important role in aerospace engineering, and it is of great significance to research on damping characteristics during its motion in the air. In this paper , the dynamic responses of cylindrical shells were analyzed using the ALE (Arbitrary Lagrangian-Eulerian ) finite element method in LS-DYNA software, and the validity of the model got verified. Then equivalent damping coefficients of the system were obtained using inversion method by the Isight software, which were verified by comparing with corresponding models . The results indicate that the inversion damping coefficients can be used to replace the ALE method in simulating cylindrical shell’s motion in the air, while the stiffness and mass have little effect on damping coefficients.

Abstract:In comparison with the conventional lift-fan UAV aircraft, the lift-fan with spoilers has great differences in kinematic consideration and controlling mode. What the main key of kinematic consideration is manipulative performance. However, there are few researches, reports or references on it. Therefor in order to obtain the dynamic characteristics of this kinds of power system(lift-fan with spoiler), a set of Dynamic Data Acquisition (DAQ) system based on LabVIEW was designed and produced in this paper, including experimental data input and collation of dynamic characteristics. According to the output and the succedent process of model, it indicated that the system was efficient as well as proper.

Abstract:With the optimization design, the non-axisymmetric end wall in a high pressure(HP) turbine stator row was optimized based on the methods which combined end wall parameterization, three-dimensional Navier-Stokes(N-S) flow computation, and genetic algorithm(GA) ground on artificial neural network(ANN). The objective of optimization design is to minimize the total pressure loss coefficient and secondary kinetic energy(SKE) at the stator exit while the inlet mass flow, the exit Mach number and the exit flow angle are controlled. This paper compared and analyzed the influences on the parameters at the stator exit and the stage performance of the HP turbine between the axisymmetric end wall before optimization and the non-axisymmetric end wall after optimization. The analysis results indicate that the optimized non-axisymmetric end wall can effectively improve the flow field through suppressing the development of secondary flow vortex system in the HP turbine stator so as to reduce the flow loss at the stator exit. And the total pressure loss coefficient at the stator exit reduces by 14.85%, while the stage isentropic efficiency increases by 0.456%.

Abstract:The handing characteristics degradation of Carrier-based Aircraft in the Low-speed high angle of attack situation and the interference of the airflow disturbance can cause that Carrier-based Aircraft carrier landing failed if the Carrier-based Aircraft cannot be controlled well. This article focuses on building a carrier-based aircraft landing dynamics model that consider height affect, and analysis of the physical mechanism of carrier-based aircraft landing process. Designed Fuzzy PID control system for different Control channel, through comparative and analysis, draw their strength and weaknesses. Filter out the throttle lever height feedback PID controller as a control system under the airflow disturbance. Simulation results verify the effectiveness of the controller.

Abstract:Ducted propeller design requires a long time for the complexity of the mutual interaction between duct and propeller. A simple method was proposed for the purpose of designing the blade geometry during ducted propeller preliminary design stage in this paper. The mass flow through the propeller disk was calculated using the momentum theory and the incremental differential pressure before and after the propeller disk was estimated by applying the engineering experience. After the two steps, the blade primary geometry was designed in the basis of blade element theory. To verify feasibility of this method, the paper manufactured the blade and duct, and tested them in wind tunnel .The result shows that the design value approximates to the wind tunnel experimental results, which illustrates that the method is useful and effective. This method can accelerate ducted propeller design procedure.

Abstract:To improve the sensitivity and dynamic performance, this paper presented a new type of flexible hot film sensor with a cavity underneath for thermal insulation. With FVM simulation and dynamic performance analysis, the structural parameters of the cavity were determined. The double side micro-fabrication processes of flexible hot film sensor with the cavity underneath were proposed. The static and dynamic performance of two kinds of sensor were studied in wind tunnel. Compared with the sensor without cavity, the new sensor shows 20% output increase with the same input and time constant drop from 400μs to 220μs. This means higher sensitivity and dynamic response speed were obtained.

Abstract:The Quiet Spike is a telescoping forward fuselage extension that alters the bow shock of the classic N-wave pressure signature generated by aircraft travelling at supersonic speed. The bow shock is broken up into sequence of weak shocks that parallel to each other with coalescing. Supersonic airliner of the "shuttle" layout is analyzed in the paper. Based on CFD and waveform parameter method, different geometrical parameters of multi-segment quiet spikes are studied. The results demonstrate that the impact of quiet spike to supersonic airliner’s sonic boom is remarkable. The sonic boom is reduced distinctly by well-designed quiet spike. The sonic boom is remarkable affected by the segments. The well-designed multi-segment quiet spike has better capability for reducing the sonic boom than single-segment quiet spike.

Abstract:Fault injection, an estimation method based on experiments and an important component of integrated vehicle health management, plays an important role in vehicle safety. This paper describes the principle of fault injection. Several methods of fault injection and their applications in aircraft are reviewed in detail. Emphasis is put on the analysis of the pivotal technique used and the technical difficulties faced when fault injection technique is applied to structural, thermal-protection, hydraulic and mechanical systems of vehicle. A prospect in this field is described at the end.

Abstract:A concurrent subspace optimum design method for composite stiffened panel is proposed. It divides the entire optimization into three sub-optimixations, that is layout optimization, size optimization and ply optimization, and the variables of them are the form of the stiffeners, the size of stiffeners and the ply thickness. All the sub-optimizations are solved independently. Once the three sub-optimizations finished, the values of the variables are reset according to the optimization results, and then to repeat all of the above until the convergence requirement is meet. The optimization design of three composite stiffened panels is conducted to demonstrate the effectiveness.

Abstract:Research on folding-wing aircraft is expanding in global research field. General aircraft shows characteristic of single optimum aerodynamic performance in executing missions. Folding-wing aircraft adapts to multiple-mission flight because aerodynamic performances can be changed if wings are folded or extended. This paper designed a folding-wing aircraft and used Computational Fluid Dynamics (CFD) simulating results to analyze the aerodynamic performance. The CFD simulating results indicate that the stalling angle, diving performance, aileron efficiency, longitudinal stability and controllability, lateral stability and controllability are affected strongly by the folding angle. The stalling angle of attack becomes large and the plane dives quickly if the wings are folded.

Abstract:The aircraft brake system design environment is built to improve the scheme design efficiency and quality of aircraft brake. The rapid determination methods of brakes and anti-slip control system parameters are studied, the iterative method is adopted to meet the design issues. The dynamic characteristics of brake system and performance of brake device are estimated. The model of brake system built in MATLAB/Simulink is called by MATLAB engine to do dynamic analysis. The brake system of a UAV designed as a example works well, and coincides basically with the actual working condition, the results show that this paper provides a rapid effective method of aircraft brake design.

Abstract:By combine servo, worm gear mechanism, parallelogram mechanism our design meets the wing’s transformation structure requirement of morphing aircraft. We designed the fold-angle measurement algorithm and control system based on three 3-axis accelerometers and DSP processor. With the accelerometer, we can get the angles of both fuselage and wing in relation to the reference coordinate system, and then we can get the result angle by taking subtraction. In addition, a small-size plane model with foldable wing was made to test these design. The test shows that the wing has the ability of steadily fold to any given angle in the range from 0 to 90, the measurement algorithm is precise and the error of fold angle is acceptable.

Abstract:Expression of MBD data sets and method of skeleton model designing are researched in this paper. Working principl of associated design is explained. MBD data sets is the sole data resource during the aircraft research. With the definition of general skeleton and interface skeleton and assembly skeleton based MBD data sets, we can realize the associated design in design department and set up a collaborative method between design and manufacture The full 3D digital associated design technology will improve efficiency of communication between the teams and reduce mistakes of design. Change of design will be transferred quickly from top to down. The application of the technology mentioned above has enormously improved the designing and manufacturing efficiency, and shortened the product development period.

Abstract:In order to do the analysis of landing gear shimmy dynamic characteristics, it is necessary to do some research on shimmy dynamics modeling, and to develop the shimmy dynamics simulation method. Mtalab/Simulink is applied to establish a simple nonlinear shimmy dynamic model of the nose landing gear, and some examples are provided. The simulated model is proved correctly by result comparision.

Abstract:Phenolic foams were prepared by compression molding mixng phenolic resin with hollow phenolic microspheres by different volume ratio, followed by carbonizing at 900 °C under Ar to produce carbon foams composites with hollow carbon microsphere structure. Microstructure of carbon foams were studied. Effect of content of microspheres on compressive properties and fracture toughness of carbon foams were investigated. The results show that compressive fracture characteristics of carbon foams change from gradient-brittle fracture to pseudoplastic with increasing content of microspheres, fracture toughness of which obviously improved for same change. Fracture toughness of CF-80 performs better than others. The specific compressive strength of carbon foams could be improved by increasing content of microspheres properly, and that of CF-70 is up to 43.32 MJ.kg_-1.

Abstract:Engine installation is one of the most important factor in the aircraft design. Engine installation must be comprehensive considering the impact on the performance of aircraft. As an structure to be passed engine power, pylon is very important structure. According to the characteristics of wing-Mounted, analyzes the influence of engine installation on the performance of aircraft. And several pylon structure, and some form of connection between pylon and wing, pylon and engine are introduced. The results show that the front engine position is more conducive to the design of aircraft. And taking into account our country’s level of technology, consider the safety of the aircraft, the maintainability of pylon and systems, the form of box beam pylon, and the statically determinate connection between pylon and wing, the engine body connection between pylon and engine is the preferred solution for pylon design.