Advanced Materials Research Vol. 1016

Abstract: Spacecraft thermal design is a process of energy management in which environmental heating plays a major role. This paper is aimed at modeling and analysis of the orbital thermal environment by considering the external heat radiation, for the inclined-LEO cubed satellite with 3-axis stabilized (to Earth state).The result indicates that the analytical model simplifies the analysis of orbital thermal environment and the absolute value of angle on inclined orbit can vary from 0 to a maximum which equals to the sum of orbit inclination and the maximum declination of the sun. Finally, for the inclined-LEO small satellite, the extreme thermal case should fully take account of the point of.

Abstract: This paper introduces a new approach for the identification of linear state-space models of dynamical systems of arbitrary complexity. The identification procedure is described and applied for modeling aeroelastic response of helicopter main rotors. With the aim of developing a tool that might be conveniently applied for real-time simulations of helicopter flight dynamics, the state-space model considered is a reduced-order description of loads transmitted to the airframe due to hub motion and blade pitch controls. In order to validate the proposed approach, loads from the state-space, reduced-order model are compared with those predicted by the complete full-state, nonlinear rotor model for prescribed helicopter maneuvers.

Abstract: The paper provides a method applicable for the determination of flight loads for maneuvering aircraft, in which aerodynamic loads are calculated based on doublet lattice method, which contains three primary steps. Firstly, non-dimensional stability and control derivative coefficients are obtained through solving unsteady aerodynamics in subsonic flow based on a doublet lattice technical. These stability and control derivative coefficients are used in second step. Secondly, the simulation of aircraft dynamic maneuvers is completed utilizing fourth order Runge-Kutta method to solve motion equations in different maneuvers to gain response parameters of aircraft due to the motion of control surfaces. Finally, the response results calculated in the second step are introduced to the calculation of aerodynamic loads. Thus, total loads and loads distribution on different components of aircraft are obtained. According to the above method, abrupt pitching maneuvers, rolling maneuvers and yawing maneuvers are investigated respectively.

Abstract: Longitudinal dynamic derivatives of an airfoil oscillating in pitching and plunging motions were calculated using variation of pitching moment coefficients with angle of attack in various conditions, based on wind tunnel data. The effect of reduced frequency on variation of longitudinal oscillatory derivatives was investigated, in three different regions of oscillation: before, over and post stall conditions. The results showed that reduced frequency has significant effects on longitudinal oscillatory coefficients in different conditions for both types of oscillations.

Abstract: This paper presents a SOA and cloud computing based architecture for the distributed simulation of advanced flight management system (FMS). The architecture is designed to facilitate the fast simulation, validation and evaluation of different FMS system designs and functionalities with customized system configurations and widely varying aircraft equipage levels under various operation conditions. It is also intended to accommodate the potential evolutionary extensions of new avionics concepts and functionalities such as the future CNS/ATM and 4-D trajectory based technologies. To address the requirements of flexibility, scalability and reusability, the design of the simulation architecture takes advantage of the cloud computing and service oriented architecture (SOA) and the key enabling technologies are developed: simulation unit service encapsulation, simulation agent technology and simulation orchestration. Based on the proposed architecture associated technologies, the simulation components are encapsulated as services or accessed through agents, and the configuration of different FMS system frameworks and simulation tasks can be achieved through simulation orchestration. A prototype avionic simulation system that implements the SOA/cloud computing architecture is developed and illustrated with application cases. The applications demonstrate that the proposed architecture enables fast and scalable simulation of both existing and new FMS design and technologies.

Abstract: The physical model, procedure of fitting parameter extraction and experimental study of the contribution of radiation induced charge neutralization (RICN) effect on enhanced low dose rate sensitivity (ELDRS) of bipolar devices are presented.

Abstract: The technique for low dose rate response prediction, based on the combination of low, room and elevated temperature irradiation was described. The possibility of using Test Method 1019.8 for space applications was considered.

Abstract: In this study, a numerical experiment was performed as what obtains relative velocity fluctuation by oscillating an object with comparatively large amplitude in the direction of flow. Follow pattern and instantaneous fluid force around an In-line forced oscillating symmetrical airfoil (NACA0012) with attack angle of 5 degrees caused not separation in stationary situation were investigated using a vortex method at the Reynolds number Re=4.05×10⁵, in ranges of the oscillation amplitude ratio 2a/c=0.5,1.0,1.5 and 2.0 and the oscillation frequency ratio f/f_K=0.25,0.5,1.0 and 2.0 (here, a :half-amplitude of oscillation, c :chord-length, f :oscillation frequency, f_K :natural Karman vortex shedding frequency from a stationary airfoil with the attack angle of 90 degrees). As a result of calculations, Separation was observed by oscillating condition even if it was the airfoil of attack angle not separating. It is found that the separation was dependent on the velocity ratio. The characteristics of fluid force are changed by oscillation.

Abstract: The research on dynamic derivative under the dynamic unsteady condition is one of the most difficult aspects of the aircraft development process. For the special experiment of dynamic derivatives, no numerical simulation of support interference has yet been systematically studied. The numerical simulation of support interference for identification of dynamic derivatives with 7o blunted cone under the hypersonic condition was done in this paper. The 2-order Roe scheme and the dual-time-step method based on LU-SGS were respectively applied to discrete of the spatial and time derivative of the unsteady flow. A least square method based on the Etkin unsteady aerodynamic model was used for identification of dynamic derivatives. Hypersonic missile module was adopted as a verification example, and the numerical calculation results are consistent with the experimental results. For two different sting support forms with 7o blunted cone, the impact of sting support interference on dynamic derivatives was studied. Results show the moment coefficients of two support forms under static conditions are essentially the same, while there is a big difference in the pitch damping derivatives under dynamic conditions. The support interference of nonlinear aerodynamic loads resulted from the shock wave induced separation and other unsteady flow structures under dynamic conditions is far more complicated than that under static conditions, and the correction law of support interference under static conditions cannot be applied directly to the unsteady dynamic situations.

Abstract: To achieve short-take-off-and-landing (STOL) performance, numerous airframe/propulsion integration (API) technologies have been developed for military and commercial transports. Powered lift technology refers to a concept of utilizing the propulsion exhaust flows to increase lift through an increase in wing circulation []. Over the past seventy years, various concepts have been explored to accomplish this goal. From the point of view of technical characteristics, powered lift concepts can be sorted into three groups: a circulation control wing, blown flaps, and jet wing. Most of other concepts are slight deviations of these three.