Abstract:Limited by the applied conditions and environments, aeronautical radar absorbing materials (RAMs) need a higher temperature request. Because of narrow absorbing frequency, poor properties of radar absorption at lower frequency and anti-oxidation, the applications of traditional high temperature RAMs are limited. In this paper, some new high-temperature RAMs, such as ZnO and its composites, Ti₃SiC₂ and its composites, were reviewed in detail. Problems faced with high-temperature RAMs were summarized and the future developments of high-temperature RAMs were prospected．

Abstract:The supersonic flow (Ma=2.0) past vane types of micro-ramps have been simulated to improve the characteristics of isolator. The findings of the study are as follows, MVG with high frontage generated stronger streamwise vortex, the total pressure distortion and Ma number distortion decreased but brought higher total pressure loss. The wide frontage of MVG not only has no use to improve flow control characteristics, instead of causing more total pressure loss. Flow filed controlled by MVG which has no wide frontage and high frontage could suffer higher back pressure and increase skin fraction coefficient may correspond to delayed separation and a smaller interaction region.

Abstract:Considering LU-SGS and GMRES have been successfully applied into unstructured grid finite volume method as two main implicit iterative methods, they are combined with p-multigrid method in this paper and the overall acceleration performance is studied. The convergence acceleration of p-multigrid method is achieved through the recursive iterative solving of different order polynomial approximations. In order to achieve better convergence effect, implicit scheme is implemented on the lowest-order approximation while explicit schemes are implemented on the higher-order approximations. The transonic inviscid flow around NACA0012 airfoil and ONERA M6 wing were simulated. The numerical results show that, compared with the explicit TVD-RKDG method, convergence rates for the p-type multigrid methods, which adopt LU-SGS or GMRES scheme on DG (P₀) layer, have been significantly improved, while the performance of GMRES iterative method is best and LU-SGS iteration is secondary.

Abstract:To analyze flow characteristics of the cantilevered ramp injector in supersonic combustion, the numerical simulation was carried out to investigate the effects of cantilevered ramp injector on ethylene injection. Several conditions were carried to analysis about the influence, such as: with and without cantilevered, swept structure and unswept structure, different kinds of cantilevered structure. It is found that the cantilevered ramp structure can enhance the mixing effects and increase penetration depth, comparing with ramp injectors. Swept structure can effectively enhance the streamwise vorticity in the flow field, so as to enhance the mixing effects, but also bring higher total pressure loss. Triangular cantilevered structure can’t enhance the streamwise vorticity, and so as not to enhance the mixing effects, but bring lower total pressure loss. There is no obvious difference between two kinds of swept cantilevered ramp structure’s flow fields.

Abstract:since many compenments of aircraft landing gear could be regarded as cylinders, so it could be feasible that through studying tandem cylinder’s noise control method to investigate the possibility of controlling landing gear’s aerodynamic noise using plasma.The incoming flow speed was 34m/s, 51m/s, 68m/s and 85m/s respectively, four pairs of plasma actuators was amounted on the rear surface of upstream cylinder. It was shown that using active flow control method based on plasma actuation，the maximum sound pressure level in one frequency reduced up to3dB; the maximum of overall sound pressure level reduced up to3dB;at the same time, the plasma affected the cylinder noise’s peak frequency, the second tone frequency was about 390Hz when plasma actuation working ,while when plasma actuation was off, the second tone frequency changed to 510Hz.

Abstract:In the traditional aerodynamic design of aircraft/engine integration, engine system was usually modeled by the flow-through nacelle, but it is very different that the simulation of intake and exhaust effects by flow-through nacelle compared with actual engine work conditions. To improving ability on this problem, the research had be done about the interference of the powered effects to high speed buffet characteristics on the cruise configuration of a civil aircraft with method of solving RANS equations on multi-block structured grid system. Firstly, it was verified that the powered effects can be modeled by intake and exhaust boundary conditions. Secondly, the method that it can be used to judge buffeting onset is given by comprehensive consideration of calculation accuracy and efficiency in the preliminary design stage. Analysis shows: the powered effects had a bad interference to buffeting onset that was designed based on flow-through nacelle at the cruise Mach number, lift coefficient of buffeting onset was reduced about 1.3% of total. We suggest that the effects of power of engine should be considered when checking buffet constrain for the configuration designed based on the flow-through nacelle.

Abstract:With the system’s complexity increasing, the accident caused by human errors is also increasing, traditional safety analysis methods, such as FTA and FMEA that based on the linear chain of events, can’t identify the system risks caused by human errors. So in this paper we used the system-theoretic process analysis (STPA) method to identify the potential safety risks of the combat aircraft’s IFTF(Integrated Fire, Thrust and Flying) caused by human errors. The paper first built a STAMP model of the combat aircraft’s IFTF, then built the STPA safety analysis model of the combat aircraft’s IFTF. In the end, according to the 5 kinds of accident factors proposed by the paper, identifying the risk factors of the combat aircraft’s IFTF’s UCA(Unsafe Control Action) without involving the safety requirements and constraint. The paper’s results laid a solid foundation for the further safety analysis.

Abstract:In order to obtain load path of landing gear and evaluate load path impact of geometry nonlinear and static indeterminacy, meanwhile to explore method of building FEA beam model of landing gear. The FEA beam models of specific type nose and main landing gear with feature of local static indeterminacy were built by way of HyperMesh and Ansys co-simulation. Static calculation of three load cases was conducted using the FEA model. The boundary load and section load of landing gear with feature of static indeterminacy and geometry nonlinear was obtained, and fore/aft stiffness, lateral stiffness and torsion stiffness of the gear was obtained under one unit load. Comparison with traditional method was conducted. Some conclusion was made: (1) There was difference between boundary load of the two methods. Some difference exceeded ±10% and the biggest difference achieved 30%. (2) The traditional method and simplification of calculating section load of level beam and inclined beam of nose strut was reasonable and had guidance meaning of design nose strut.

Abstract:Based on the secondary development of ABAQUS, we construct a method of material degradation principle and established a 3-D progressive damage model. Through numerical analysis of damage propagation and damage properties among composite material constructer in different lay proportion, we get a good result. Summarized from simulation and numerical analysis above, lay proportion had an important impact in bolt joint constructer made of CCF300/BA9916-II composite material. To improve the anti-pressure ability and anti-cut ability of strengthening area around hole, we properly added the proportion of ±45° layer. At the same time, when this proportion added to 50%, there were no more effects in improving the strength of bolt joint of composite material.

Abstract:With the rapid development of aviation transportation,the traffic density increases gradually,the airport runway and taxiway system becomes complex.Aviation safety problems stand out.Among them the runway incursion is an important aspect.There are many causes of runway intrusion,this paper focuses on human factors affecting the runway incursion severity classification.Based on the runway incursion severity classification,the writer adopts multi-attribute risk assessment model to quantify the runway incursion severity classification.And try to illustrate the feasibility of this method in quantification of runway incursion severity classification through examples.Finally,the writer points out the problems in practical work through analyzing obtained data.

Abstract:Pilot Induced Oscillation (PIO) is a safety issue which is concerned by airworthiness authorities. Firstly, I and II PIO susceptibility of a civil aircraft are calculated and analyzed by engineering prediction criteria. Secondly, according to AC25-7A, flight test methods and evaluation criteria of PIO are proposed. Finally, confirm whether it has PIO susceptibility by analysis of flight data and pilot comments. The flight results show that there is no any PIO susceptibility in flight test period and the civil aircraft meets the minimum allowable HQRM requirements. Furthermore, the flight results are consistent with prediction.

Abstract:Preventing from considerable modification for design，influences of aeroelasticity should be considered in most stages of aircraft design, and conceptual design is no exception. The new region jet is a 120-seat-class airliner. A general process, theoretical bases and methods of aeroelastic design in aircraft conceptual design was summarized in this paper. Taking the known technical requirements and parameters related as input, a beam-frame model of wing was developed. Based on the model, the stiffness and mass distribution was designed. Then an analysis of static aeroelastic responses, flight loads, vibration characteristics, and flutter characteristics was carried out. The results indicate that the aeroelastic design of the new region jet is well satisfied with the requirements.

Abstract:It is of significant importance to calculate the stability derivative accurately for stability and control of an aircraft. Dynamic mesh technology in computational fluid dynamics(CFD) are used to simulate periodic pitching oscillation motion of finned missile circling around a fixed axis. The hysteresis curve of pitching moment coefficient for the basic model Finner missile was obtained at different Mach number. The static derivatives of the missile in different Mach numbers were computed with difference method, line method and Least-square technique. The minimum error can be 0.5% compared with experimental data.; Dynamic stability derivatives were coumputed at different Mach numbers with integral method, Least-square technique and hysteresis-circle method. The error is between 5.8% and 23.8%. The results show that the method in the paper can correctly compute the static and dynamic stability derivative of finned missile and it can make a reference for engineers.

Abstract:Execution procedure and feature of CO/RSA is analyzed and building method of RSA is introduced. In this paper, multidisciplinary models of stratospheric airship are built and the coupled information in subsystem analysis is supplied by the RSA. In addition, the system optimization model and three subsystems, including aerodynamic/propulsion, structure, and energy subsystem, are discussed in detail. The design object is to find a feasible airship based on CO/RSA, which is with minimum total mass and satisfies the constrains including three balances: the balance between the energy supply and the energy requirement, the balance between mass and buoyancy, and the balance between drag ant thrust. The optimization result verified the rationality of MDO and CO/RSA in stratospheric airship’s conceptual design. Moreover, a reference of stratospheric airship program demonstration and design is provided.

Abstract:：After more than 10 years of theoretical research on MBSA, Now it has been applied on several aircraft safety design and analysis. MBSA can offset the lack of safety analysis, It represent the development trend of military and civil aircraft safety analysis. First the paper set forth the shortcoming of safety analysis, Then introduce the application and advantage of MBSA, Finally in combination with the process of safety analysis, Preliminary build the process of safety modeling and analysis.

Abstract:EBOM(Engineering Bill of Material) applied in Aircraft field is the deliverable which Design Department of Aircraft Engineering should provide to Procurement, Methods and Project Department as the basis of purchasing and manufacturing controlling. Whether the information is ample or deficient, whether the format is standard or nonstandard, whether it is easy to read or not, they all represent the work quality of Design Department to some extent. Taking the relatively standard EBOM practically applied in one Civil Airplane Project as the original version, and the Excel tables as applying platform, the necessary property information has been customized, and one set of method and workflow has been customized by use of the functions of Excel. The workflow of formatting EBOM has been programmed, which tremendously improved the efficiency and quality of making and updating EBOM.

Abstract:Fuselage sealing technology is a key factor affecting the fatigue life of aircraft, the use of economic life, repair and safety, reducing the sealing failure caused by corrosion of the body and improving the sealing ability of civil aircraft fuselage is the inevitable trend of the development of civil aircraft manufacturing. Commercial aircraft fuselage sealing types, property of sealant are analyzed. According to the sealing process requirements and structural features, the proposals of sealant application method are presented. The casual of sealing failure are introduced and conclude with failure rework method for typical structure sealing to ensure the safety and service life of aircraft.

Abstract:Bayesian network (BN) modeling problem has always been the bottleneck of its application in the field of fault diagnosis. Aiming at the problem of fault diagnosis of complex equipment, a BN modeling technology based on failure mode, effect analysis (FMEA) knowledge is presented. First, a method of building a BN segment based on a single unit of information of FMEA is proposed after studying the failure information that FMEA includes. Then a system’s BN model can be built by connecting all the segments is put forward. At last, a BN model that describes an aircraft’s front wheels turning system is built and analyzed. The model exemplifies that the BN model based on FMEA presented in the paper not only avoids the need for a large amount of engineering experience in the traditional modeling process, but also breaks the FMEA qualitative analysis ability , which can make quantitative analysis on a system and can perform fault diagnosis on a system effectively by fusing multi-source information.