Abstract:Landing Gear is one of the most important components of the aircraft. The design of the landing gear shock absorber has to be validated by drop tests. In May 2001, FAA issued the Amendment NO.25-103 to revise landing gear drop test requirements. The reason of issuing this amendment has been described. Based on the content of the amendment, a careful comparison between the amendment and CCAR25 Revision R3 and an impact analysis has been made. According to the comprehension of the landing gear dynamic characteristic, compliance approach for drop test has been elaborated. The investigation results show that the there is no any essential difference for the drop test method, but more critical requirement has been made for the test purpose. This investigation can be a useful reference for the landing gear drop test certification.

Abstract:The hole stress concentration of composite plate is studied by FE method for designing the composite mechanical connections. The relations between the stress concentration and the d/B、H/d is concluded in the paper: (1) The relative width d/B and relative edge distance H/d have a great effect of stress concentration. (2) The maximum circumferential concentration factor decreases with the increase of H/d, but ratio of maximum radial stresses to bearing stress almost has no change. (3) The ratio of maximum circumferential stress to bearing stress increase with the decrease of B. As d/B changes, the Krd almost has no change, but the radial stress changed visibly. These results can be referred to design composite mechanical joint.

Abstract:Simulation analysis using Detached Eddy Simulation is performed to simulate the flow field around the simplified structure including the strut and torque link of an aircraft’s nose landing gear. The acoustic field radiated from different model parts and total model are calculated via FW-H equation. The noise mechanism and acoustic characteristics of the noise from the structure are analyzed. Wind tunnel test is performed to measure the noise spectra of the structure by microphones. The simulation and experiment results show that the noise of the assembly of strut and torque link include bluff body and interaction noise. Noise from the strut has greater contribution to total noise than that from the torque link. The whole model noise radiation directivity is similar to the dipole characteristics.

Abstract:As the key part of more-electric aircraft(MEA), the more-electric engine(MEE) is brought high attention of foreign country. The research status and developing trends of MEE are reviewed in this paper. Then, the advanced technical characters of the key components such as integral starter-generator，magnetic bearing，electric pump and electric actuator are analyzed. Finally, the key technology of high temperature interior integral starter-generator，active magnetic bearing and distributed control are discussed.

Abstract:Aiming at improving independent innovation to develop commercial aircraft of China, this paper reviews the development as well as circumstances of aeronautical education in China and points out existing problems. The paper also analyzes the modes and the practices of the education of all-purpose aeronautical engineers world-wide, and summarizes the educational reforming of the modes for nurturing aeronautical engineers in BUAA, NPU and etc. from the perspective of international and innovational standards, and proposes the objectives, the patterns and the scheme of the education of all-purpose aeronautical engineers for the current needs.

Abstract:In this paper, the way of helicopter low speed flight test has been introduced ;the trim flight characteristics has been analyzed according to the result of the forward and backward and sideward flight test of the sample helicopter. The influence of aerodynamic configuration on the low speed flight test characteristics has been analyzed, the optimization of the aerodynamic configuration has been proposed.

Abstract:Pin load computation is crucial for strength analysis since joints with multi-rivets or multi-bolts are fatigue details of aircraft structures. In the paper, four finite element models based on MSC.Nastran are carried out to determine the load distribution of a lap joint with multi-bolts in rows. By comparison, the method modeling fastener with combination of CBAR, RBAR and CBUSH is presented to be convenient, effective and precise and is a better application in multi-fastened aircraft structure analysis. Additionally, an example of eccentrically loaded fastener group is presented and results show the above modeling method is more accurately for determining pin load distribution than the estimating one. In conclusion, the finite element modeling method is recommended to be applied to obtain more reliable pin loads.

Abstract:Actuator rate limiting has been a causal or contributing factor for Pilot Induced Oscillations (PIO) experienced on highly augmented aircraft. The closed-loop pilot-aircraft system was the research object. The mechanism of PIO was examined. The pilot model and aircraft model about closed-loop system were set up. The effect of actuator rate limiting was discussed, The prediction methods of category Ⅱ PIO due to actuator rate limiting, OLOP criterion, were studied. A critical examination of the Open-Loop Onset Point (OLOP) criterion was conducted to see if it could accurately predict PIO due to actuator rate limiting and to evaluate its potential as a design tool.

Abstract:In view of the low reliability of the accessories of aero-engine in service, the problems that exist in the developing procedure and their causes are analyzed in this paper. According to the relational requirement of the National Military Standard, and considering the conventional structure, function character of the aero-engine accessories, the missionized/simulated operational test and the individual tests, which are not explicitly stipulated in the specification, and recently added test requirements of reliability maintenance are discussed on emphasis. The general requirements of the tests for newly developed engine accessories are proposed, and the typical example is given. This paper has instructive and paradigmatic meanings for the work of the accessory reliability of the new developed aero-engine, programming the approval test, and determining the project.

Abstract:In order to improve aircraft-arrangement quality, a multi-objective model of Aircraft-arrangement Problem with Time Windows(APTW) which covers two targets(the degree of customs’ satisfaction and plane’s minimum number) are built based on the traditional target of minimum cost. After dealing with three target functions by process, the Quantum discrete PSO is employed to solve the model which cites data from the internationally recognized question database of aircraft-arrangement problem. Finally, both result of the model and the time that solve the mo-del belong to the ideal range, which indicates that the new model is feasible. The building of the model which is helpful to optimize aircraft-arrangement problem with time windows can improve logistic efficiency effectively.

Abstract:In order to confirm the performance of detonation initiation and propulsion, the corresponding detonation initiation and propulsion experiments at different operation frequencies was carried out in this paper, based on the direct-connected test of a gasoline/air pulse detonation engine mockup. The results indicated that detonations were fully developed quickly in the PDE mockup at the operation frequency range of 0~35Hz, in which the deflagration to detonation transition (DDT) distance was about 0.9m (from the ignitor). As the operation frequency increased, the PDE average thrust increased nearly linearly while the increasing slope decreased slightly. The volume specific impulse and mixture specific impulse have the similar change trend with the operation frequency, which both increased at the increased operation frequency. The maximums of volume specific impulse and mixture specific impulse were both obtained at the operation frequency of 25Hz. Meanwhile, the fuel specific impulse increased dramatically and the specific fuel consumption decreased dramatically at the increased operation frequency of 0~25Hz. When the operation frequency exceeded 25Hz, the fuel specific impulse and specific fuel consumption changed slightly.

Abstract:Air system is mainly used for cooling the engine hot components and cabin air conditioning, and supports the safe and reliable operation of aircraft engines. Air system is closely related to the aerodynamic performance of the compressor for it changes the air flow within the compressor by extracting bleed air from the compressor. The flow rate of the air system keeps growing to meet the demand of multiple aircraft functions, various external environment and higher turbine inlet temperature. The growing flow rate of air system highlights the impact of air system on the compressor aerodynamic performance. This paper analyzes the characteristics of the air system bleeding, sums up the progress on the research of the interstage bleeding of the compressor both home and abroad, and explores the future development and application of the air system bleeding research.

Abstract:This paper presents the challenges and the general requirements that companies face in deploying Simulation Data Management in aerospace industry, defines the key necessary elements of such environments, indicates the benefits that SDM can deliver, and describes the solution how responds to those needs. This paper provides multi-discipline CAEBOMs concept which how to manage structural simulation data . It emphasis on simulation process how to synchronous with product design process and integration with external simulation tools. Some best practices are introduced for SDM application in this field.

Abstract:On the basis of analyzing the green aviation requirements, FAR noise standards, air frame noise sources, this paper discusses the state of the art of aero-acoustics techniques including CFD, wind tunnel test, flight test and noise reduction in details. The importance of aero-acoustics research on high-lift devices is indicated, and the future trend of high-lift devices aero-acoustics——the aerodynamic integrated aero-acoustics high-lift devices design,is clearly pointed out.

Abstract:In order to obtain the optimum performance data of the extraction aircrew escape system, a relevant mathematical model is establised in this paper on the basis of operational principle of the system and different phases of the extraction ejection event. Through the simlation algorithm, this paper gives the power complement between the ejection gun and the extraction rocket and time intervals between the front and rear cockpit occupants escaping from the aircraft according preset ejection sequences. These data provide preliminary permance basis for general design of the aircrew escape system, and the techncial program is finalized.

Abstract:Based on structural model from the ground vibration test (GVT) and the structural response at sub-critical speed, the generalized aerodynamic force coefficient vector can be solved. Generalized structural coordinate vector is designed as the input and generalized aerodynamic force coefficient vector is designed as the output. Identification technique is utilized to construct the reduced order aerodynamic model. The aeroelastic model based on experimental results can be constructed by coupling structural equation and aerodynamic equation in state space. Analyzing the characteristics of aero-structure coupling system changing with the dynamic pressure, the flutter onset behaviors can be solved by eigenvalue method. Different from the traditional flutter prediction method which needs a series of sub-critical responses, this new method only need one response at sub-critical speeds to predict the flutter onset. The new method can greatly reduce the cost and risk of flutter flight test or wind tunnel experiment.