Abstract:The integration, collaboration and intelligent development of global air transport system puts high demands on the refined management of resource scheduling in airfield area, and the efficient management and control of air traffic operations. This work focuses on the basic concepts and framework of airfield resource scheduling problem, which is part I of the whole research. The basic concepts of the airfield area are discussed from the perspectives of international conventions, theoretical research and industry regulations, and the general processes and connotation of airfield resource scheduling are analyzed. Then, the framework elements of theoretical methods, system tools, management mechanisms, and the logical relationships among the elements are systematically summarized. This paper is aimed to provide scientific guidances and references for the sustainable development of theory and practice in airport operation management.

Abstract:Resonance sound absorption structure is a sandwich structure composed of perforated panel, honeycomb and rigid backplane. This structure is widely used in aircraft engine nacelle and has achieved good noise reduction effect. With the development of acoustic theory and manufacturing technology, the resonant sound absorption structure has gradually developed from the initial single-degree-of-freedom to multi-degree-of-freedom or even embedded multi-degree-of-freedom stage, and the sound absorption effect has also made great progress. In this paper, the sound absorption principle of resonance sound absorption structure is elaborated in detail first, and on this basis, the development about liners of aircraft engine nacelle at home and abroad is introduced. Two development trends of liners are pointed out: seamless liner and multi-degree-of-freedom liner. The latest research progress on multi-degree-of-freedom liner in China is briefly introduced also.

Abstract:The Additive Manufacturing(3D Print) was widely studied and used in recent years, but there wasn"t a systematic, distinct and accurate classification about the Additive Manufacturing. The Additive Manufacturing was divided into 3 sorts and 13 sub sorts according to the category and state of the added materials and heat source of the manufacturing in this paper, as well as the principle, characteristics and trend of the each sorts of the Additive Manufacturing method were analyzed.

Abstract:Airfoil stall and its boundary layer development are fundamental scientific issues in aircraft design. For the trailing edge stall airfoil, The transition model coupled the Mentor k-ω SST model with the disturbance amplification factor transport equation is used to analyze the influence of Reynolds number variation on the laminar-turbulent transition boundary layer characteristics and stall characteristics. The results show that when the Reynolds number increases, the local vorticity Reynolds number increases, the transition position moves forward and the separation bubble decreases, the flow energy dissipation decreases, and the overall surface shear effect of the airfoil increases. The kinetic energy is more abundant, the flow self-sustaining ability is enhanced, and the pressure distribution can maintain the gradient resistance of the longer distance to enhance the separation ability; Therefore, the increase of the Reynolds number increases the airfoil stall angle and the lift coefficient.

Abstract:Slat noise is largely dependent on its structure parameters which are geometry and morphing parameters. The investigation of the effects of these two parameters on the features of flow and noise for an airfoil is an effective method of developing techniques for the slat noise suppression. Firstly, Three-element airfoil model 30P-30N is employed to establish the model of investigation for analyzing the flow and noise features. Based on RANS and LES methods, steady and unsteady characteristics of the airfoil flow are studied for typical geometric (overlap, gap and rotation angle)and morphed profiles (morphed tailing edge of slat seals the gap). Then the corresponding distributions of pressure and turbulent kinetic energy are obtained. Secondly, FW-H acoustic analogy formulation is employed to solve the far-field noise radiation for the slat. The inter-relationship of various slat structure parameters with the far-field acoustic pressure level and its directivity features are investigated. Finally, based on various slat structure parameters and their flow and noise characteristics obtained, the interaction of slat noise attenuation and its corresponding lift changes are analyzed and discussed. The results show that the slat geometry and structural deformation parameters can effectively reduce far-field noise radiation, but the lift coefficient will be reduced to some extent when the angle of attack increases.

Abstract:The aerodynamic design of tiltrotor must be synthetically considered to meet the different requirements between helicopter mode and fixed-wing aircraft mode, a set of optimization design methods for aerodynamic shape of tiltrotor is established by multi-objective genetic algorithm based on Kriging surrogate model. In order to improve the efficiency, the Latin hypercube method is employed to generate the initial sample points, and the Kriging surrogate model is built to replace the numerical simulation of flow. The objective function of optimization is maximum hovering thrust and cruising efficiency, with constraints of non-increasing hovering power and non-decreasing cruising thrust. The results show that, the hovering efficiency of optimized rotor is 71.0%, and the cruising efficiency of optimized rotor is 63.1%. The optimized rotor is predicted by unsteady CFD (Computational Fluid Dynamics) simulations and validated by wind tunnel test which show the good agreement between two methods. Also, the result of optimized rotor meet the design requirements and it indicates the reasonability of optimization method and numerical simulation.

Abstract:In order to study the aerodynamic characteristics of cyclorotor in hovering, the accuracy of the calculation method applied to the aerodynamics calculation was verified with an example. Then, the aerodynamic parameters of cyclorotor with different radia, chord and number of blades were studied, and the aerodynamic interfere of cyclorotor with different distances was calculated and analyzed. The results have shown that with the increase of radius, the aerodynamics and the load per unit area of the blade increase; the larger the chord, the larger the aerodynamics, the smaller the load per unit area of the blade; the aerodynamics generated by the 4-blade cyclorotor is larger than that of 3-blade cyclorotor and 6-blade cyclorotor, while the blade load of 3-blade cyclorotor is the largest; the resultant deflection angle decreases with the increase of the rotational speed and the solidity respectively; with the increase of the distance among the cyclorotors, the aerodynamic loss coefficient and the resultant force deflection angle are decreased.

Abstract:In order to study aerodynamic performance of the dragonfly wing at gliding flight at different Reynolds numbers, a three-dimensional model of the dragonfly hindwing with corrugation and a three-dimensional flat plate with the same shape of the dragonfly hindwing are established. We studied aerodynamic effects of corrugation at gliding motion using the method of computational fluid dynamics, in the Reynolds number range of 1000 to 10000 and angles of attack changing from 0° to 25°(with an interval of 5°).The finding are as follows:(1)The effect of corrugation is to increase both lift and drag to varying degrees;(2)The aerodynamic effect of wing corrugation might be Reynolds numbers dependent. While Re=1000,aerodynamic performance of the dragonfly hindwing is slightly better than the flat plate over the entire range of parameters tested; (3) The effect of corrugation depends on the angle of attack, while at a higher angle of attack, aerodynamic performance of the dragonfly hindwing is slightly better than the flat plate.

Abstract:Nowadays, the mean load spectra ,which has a defect of long fatigue period,is always used in fatigue test for aircrafts.Use the severe load spectra instead,the test time can be greatly reduced.To meet the demand of full-scale fatigue test for life evaluation and respond to the requirements of aircraft strength criterion at home and abroad, this paper combines task analysis method with flight subject statistic analysis method, and develops severe load spectra for airplane structure of every subject and all subjects based on take-off and landing data of a instructional airplane . The process of spectra generation has been arranged and completed.The load spectra are determined for weighted mean, the meen plus 1 standard deviations,the mean plus 2 standard deviations,and for the 90%probability/95% confidence level.The approach to choose representative take-off and landing of severe load spectra is presented by equivalent damage calculation and statistic analysis .after the equivalent damage distribution has been examined by contrasting through K-S method.

Abstract:It is of significant importance to predict the dynamic derivative accurately for the successful design of projectile munitions. In order to get a missile’s dynamic derivatives characteristics, free oscillation dynamic test of the missile was conducted in FD-06 wind tunnel, showing test results of typical decay curves of amplitude and dynamic derivatives in pitching and rolling direction. In addition, base on the dual time-stepping approach to coupling solve of the unsteady RANS governing equations with the rigid body motion equations, the pitch and roll damping derivatives were presented. The results show that the CFD numerical simulation results are compared with the wind-tunnel test data. The results of CFD numerical simulation can provide reference for the follow engineering.

Abstract:The analysis of dynamic characteristics of damage structures is an important basis for non-destructive testing. However, there are few literatures concerning the study of dynamic characteristics of rotating beams with crack. In this paper, the transverse vibration characteristics of rotating beams with crack are investigated. Firstly, the crack effect was simulated using a torsion spring, and the lumped crack model of the beam was established. Then the Frobenius method was used to solve the vibration equation, and the series solution of the equation was obtained. The natural frequency of the damage structure was calculated, and the first two natural frequency variations of beams under different damage degree and rotating speeds was analyzed. Numerical simulation results verified the effectiveness of the proposed method. At the same time, it is found that the change of rotating speed and damage degree do not affect the natural frequency of the beam independently, there is a coupling mechanism between the two sides.

Abstract:Fracture analysis of joint structure was a difficult problems.Because of the joint structure design was complex ,It was difficult to accuracy the calculation result by conventional engineering calculation methods and finite element static strength calculation methods.In this paper, Tensile fracture failure tests were carried out on single-joint joints for 4 type of structural forms,According to the toughness metal damage criterion,Numerical calculations were used to simulate fracture failure of joint structures in tensile tests,The influence of structure form on fracture performance and the precision of algorithm were compared.Studies had showed that:At the linear elastic stage of the material,The displacement and deformation of the 4 joints were basically the same;The cross section of the joint was mainly concentrated in the center of the opening of the lug;The fracture strength of the joint can be improved by adding a lug at the opening of the lug; The effect of stud r angle and different loading rate on the fracture property of the joint was little.

Abstract:Full aircraft structure fatigue test, as a part of civil aircraft structure airworthiness verification test, is the most complicated, the most expensive and the most time-consuming. Improving the efficiency of full aircraft structure fatigue test and shortening the fatigue test cycle have always been pursued， especially for fatigue test management technique. This paper introduces concurrent engineering which is applied to full aircraft fatigue tests such as MA600, ARJ21-700, Y12F tests. The traditional serial working mode is transformed into the parallel working mode. Concurrent test management technique is summarized and proposed creatively. This paper describes the basic content and method of concurrent test management technique. It analyzes different requirements of the technique in different stages in a single test. At the same time it raises the management methods in multiple tests in the same factory. The practice shows that concurrent test management technique plays an important role in accelerating the cycle of full aircraft fatigue test. What’s more the technique is potential for further research and it has application prospects.

Abstract:In the flight test of target indication system, we are faced with the problem of how to evaluate the effect of the error of target indication system on its operational capability while evaluating its index conformance. In order to study the method of evaluating the precision and capability of target indication system, the relationship between target indication error and weapon strike effect is analyzed, and the error model of target indication system based on current point attack and predictive point attack mode of surface warship is established. The relationship between the target indication error and the weapon acquisition probability is transformed into the relationship between the target indication error and the probability of the missile terminal falling into the designated area. The results show that the target indication errors under the two attack modes obey the two-dimensional normal distribution. When the target indication errors increase, the probability of Weapon Acquisition decreases significantly. If the effect of weapon attack is to be guaranteed, the lower limit of target indication error is corresponded. The lower limit provides a reference for the flight test method of ship-based helicopter long-range target indication system

Abstract:Balance field length is one of the important technical indexes in civil aircraft design and operation, and it has a significant impaction on civil aircraft economy, safety and universality, and also is the basis of determining the aircraft decision speed. This paper does introduce the concept and calculation method of balance field length and the relation between balance field length and decision speed, and list three sensitivity analysis theories. Taking a civil aircraft as an example, research the effects of takeoff weight, airport height, wind speed, temperature, runway slope and other factors on the balance field length, evaluate the sensitivity of different factors to balance field length with the three analysis theories. The results show that the length of balance field and the decision speed increase with the increase of takeoff weight, airport height, tailwind speed and temperature, decrease with the increase of headwind speed. The effect of runway slope on the balance field length is negligible. The positive and negative correlations of those parameters obtained by the three sensitivity analysis methods are consistent, and the sensitivity of the five variables to the balance field length are ranked as follow: takeoff weight>wind speed>airport height>temperature>runway slope.

Abstract:The prediction method of unscheduled direct maintenance cost (DMC) for civil aircraft structure was studied, and the present statuses of research at home and abroad were introduced. The damage sources of structure, the constituent elements and the influence factors of DMC were clarified. The prediction procedure and basic input were provided, and a prediction model of unscheduled DMC for civil aircraft structure was established based on the engineering design data. An example about a skin panel of forward-mid fuselage was given. A series of DMC values of the maintenance tasks from MSG-3, DTA and DSEA analysis were computed and the various DMC prediction results for metal and composite skin panel were compared and analyzed. It was shown that the application of composite materials can significantly reduce the unscheduled DMC value for this structure. The adjustment coefficient was introduced to optimize the prediction model according to aircraft design characteristics, operation environment and utilization rate, and the applicability and accuracy of the prediction model were improved.

Abstract:Airports with Type II ILS is the precondition of CAT II ILS flight test. Since domestic airports with Category II operation condition are all large hub airports, many restrictions will greatly affect the efficiency of flight test. In order to increase the airports selection margin, and accelerate the test process, this paper firstly proposed a new method of carrying out CAT II ILS flight test by Type I ILS in domestic. And the feasibility of this method is analyzed in detail from the aspects of airworthiness regulations and technical requirements. The research results showed that this new method can meet the requirements of airworthiness certification and it is feasible. It’s an effective flight test method that can be applied to most airports with Category I operation condition in domestic.

Abstract:The state of routine electromagnetic actuator is invisible for the safety and guarantees organization of fuze control system, thus it is difficult to control, manage, or improve of security unit. Accounting for this problem, a new electromagnetic solenoid with character of state recognition is designed, with both triggering unit and signal feedback component added. The working principle is that, when triggering unit invokes the signal feedback component, the signal line is close-up, and state signal is outputted to indicate that the locked state is rescind; otherwise, the securing pin is locked. The test results show that, the output function of this new electromagnetic solenoid is reliable and robust, with a best-case response time of 3ms.