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Zhang Z.,Harbin Institute of Technology | Zhang Z.,Chongqing CHANGAN Industry Group Co. | Cui H.,Harbin Institute of Technology | Cui P.,Beijing Institute of Technology
Transactions of the Japan Society for Aeronautical and Space Sciences | Year: 2012

In this paper, we discover the existence of a sort of special periodic orbit around the equilibrium points of irregularly shaped asteroids and present an algorithm to accurately determine this novel orbit. Since the environment of orbital dynamics around the equilibrium points of an asteroid is similar to that in the circular restricted three-body problem (CRTBP), this article introduces the research approach used in the research of halo orbits in the CRTBP to determine the special orbits. Firstly, the dynamics of particles orbiting on irregularly shaped spinning asteroid are analyzed and then the formula to compute the positions of asteroid's equilibrium points can be deduced from the equations obtained from the analysis. Secondly, third-order approximate analytical solutions for the periodic orbit around the equilibrium points were obtained using the Lindstedt-Poincaré method. Finally, in the high-order gravitational field model, differential corrections were applied to amend the initial orbit value obtained from third-order analytical solutions in order to obtain accurate numerical solutions of this periodic orbit, which are called aureole orbits in this paper due to their similarity to the halo orbits around the Lagrangian point in the CRTBP. © 2012 The Japan Society for Aeronautical and Space Sciences.

Gong X.,Hunan University | Gong X.,Changan Automobile Co. | Gu Z.,Changan Automobile Co. | Gu Z.,Hunan University of Technology | Li Z.,Chongqing Changan Industry Group Co.
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering | Year: 2012

A surrogate model-based aerodynamic shape optimization method applied to the wind deflector of a tractor-trailer is presented in this paper. The aerodynamic drag coefficient of the tractor-trailer with and without the wind deflector subjected to crosswinds is analyzed. The numerical results show that the wind deflector can decrease drag coefficient. Four parameters are used to describe the wind deflector geometry: width, length, height, and angle. A 30-level design of experiments study using the optimal Latin hypercube method was conducted to analyze the sensitivity of the design variables and build a database to set up the surrogate model. The surrogate model was constructed based on the Kriging interpolation technique. The fitting precision of the surrogate model was examined using computational fluid dynamics and certified using a surrogate model simulation. Finally, a multi-island genetic algorithm was used to optimize the shape of the wind deflector based on the surrogate model. The tolerance between the results of the computational fluid dynamics simulation and the surrogate model was only 0.92% when using the optimal design variables, and the aerodynamic drag coefficient decreased by 4.65% compared to the drag coefficient of the tractor-trailer installed with the original wind deflector. The effect of the optimal shape of the wind deflector was validated by computational fluid dynamics and wind tunnel experiment. © IMechE 2012.

Gong X.,Hunan University | Gu Z.,Hunan University | Gu Z.,Hunan University of Technology | Li Z.,Chongqing Changan Industry Group Co. | And 2 more authors.
Qiche Gongcheng/Automotive Engineering | Year: 2012

For reducing the fuel consumption of container truck in crosswind condition, an optimization on its wind deflector is carried out. Specifically, the optimization is conducted with minimizing aerodynamic drag as objective and four dimensional parameters of deflector width, length, height and angle as design variables, 30 sample points are selected by optimal Latin hypercube design of experiments, and a surrogate model is set up based on Kriging model. Meanwhile test model is manufactured according to the results of optimization, and its tunnel test verifies the feasibility of optimization scheme. This indicates that surrogate model technique can well replace real simulation process in optimization. Compared with original deflector, the container truck equipped with optimized deflector can reduce its drag coefficient by 11.5% at most.

Tian H.,Xi'an University of Technology | Tian H.,Xi'an Technological University | Ni J.-P.,Xi'an Technological University | Jiao M.-X.,Xi'an University of Technology | And 2 more authors.
Binggong Xuebao/Acta Armamentarii | Year: 2016

In order to meet the testing requirement of indoor optical target with large detection area, two patterns of lens-light-screen's engineering realization method are studied, of which one is sector lens-light-screen, and the other is rectangle lens-light-screen. The working principle of each kind of lens-light-screen is analyzed. The luminous flux may be changed when a flying projectile goes through the lens-light-screen in different position, of which the corresponding formulas are deduced based on the photometry principle. The sensitivity distribution regularity of each kind of lens-light-screen is simulated using Matlab. It is verified by the firing tests of air gun bullets. The results show that the signal amplitude of the projectile collected by an oscilloscope is in conformity with the sensitivity simulation results, which provides a reference for the engineering design of the optical targets with lager detection area. © 2016, China Ordnance Society. All right reserved.

Chen R.,Xi'an Technological University | Ni J.,Xi'an Technological University | Hu X.,Chongqing Changan Industry Group Co.
Guangdian Gongcheng/Opto-Electronic Engineering | Year: 2016

Light screen array is applied to measure firing dispersion in range, and the structure parameters of the array influences the measuring result directly. Based on double-V shaped six-light-screen array, the influence of the structure parameter, the angles of incidence and the impact location to the measurement accuracy of velocity and coordinates are analyzed, and then the error transfer formulas are deduced. The relations between the measurement accuracy of velocity and coordinates to each influence factors are simulated and plotted in MATLAB. The conclusion provided a reference for improving the measuring accuracy and optimizing the engineering design. © 2016, Editorial Office of Opto-Electronic Engineering. All right reserved.

Hou Y.,Southwest Petroleum University | Wang L.,Southwest Petroleum University | Ma J.,Chongqing Changan Industry Group Company Ltd
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2015

Laminated flat-screen is widely used in shale shaker, study of the influence of the structural parameters and installation parameters of the shale shaker to the free vibration of the screen can provide the basis for the design and employment of the shale shaker and screen. Elastic support multi-span continuous unidirectional rectangular plate model which is simplified by using the bolt tightening method of the screen installation model is proposed, and regardless of the structure of the nonlinear characteristics of the screen. The whole screen is divided into k+1 pieces small rectangular plates by the rubber support. Based on the elastic rectangular plate vibration theory, the free vibration equation on each piece of small rectangular plates are established, the continuity conditions of small rectangular plates between each span are put forward, the transfer function of the entire screen by using the transfer matrix method is derived, and get the free vibration frequency equation of screen according to the boundary conditions. Numerical solution for free vibration characteristic equation is conducted on a version of flat-screen to obtain the natural frequency with different magnitude of bolt preload and different numbers and stiffness of rubber support bar. Date analysis shows that these three parameters are positively correlated with the natural frequency of the screen, and have effects on each other. © 2015 Journal of Mechanical Engineering.

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