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Lan J.,Academy of Military Transportation PLA | Wu Y.,China North System Engineering Institute | Hong Y.,CAS Institute of Mechanics
Advanced Materials Research

Molecular dynamics simulations have show that nanocrystalline (NC) materials can be treated as composite materials consisting of two phases of grain and grain boundary. In this paper, the incremental stress-strain relation is derived based on deformation mechanism of NC materials and internal variable theory from micromechanics point of view. The developed model is exemplified by the pure copper subjected to uniaxial tension. Implicated iteration algorithm is then employed to obtain the stress-strain relation. Moreover, the effects of grain shape and statistical distribution of grain sizes are also discussed, and predicted results are compared with experimental values to verify the model. © (2011) Trans Tech Publications, Switzerland. Source

Fu B.-B.,Science Research Institute of China North Industries Group Corporation | Lei J.-M.,Beijing Institute of Technology | Wang D.-M.,China North System Engineering Institute
Binggong Xuebao/Acta Armamentarii

On the base of theoretic analysis of gliding extended range, a mathematic model for exterior ballistics of gliding extended range guided munitions (ERGM) was established, and the maximum lift-to-drag ratio trajectory was simulated to obtain the ideal trajectory and actual trajectory. The simulation results were analyzed, and the improvement measures for the controlling system and the canard rudder surface shape were put forward to solve the oscillation problems of attack and attitude angles, thus assure the ERGM's stabilization of gliding flight. Source

Li F.-G.,Beijing Institute of Technology | Xia Q.-L.,Beijing Institute of Technology | Cui X.-X.,China North System Engineering Institute | Qi Z.-K.,Beijing Institute of Technology
Yuhang Xuebao/Journal of Astronautics

To choose a reasonable line of sight rate extraction scheme of seeker in missile general design, a useful method is present based on analysis of characteristics of seeker disturbance rejection rate parasitic loop. A model of parasitic loop were established for a typical gimbaled seeker. Then using frequency domain methods the characteristic difference of disturbance rejection rate transfer function and parasitic loop as well as guidance system are analyzed for two kinds of extraction scheme. The effect of guidance parameters on the parasitic loop stability region is studied with Routh criteria. Using an infrared image seeker's parameters, simulation is done under typical flight condition to confirm the theoretical analysis. The study shows that the parasitic loop can change characteristics of guidance system, and line of sight rate extraction schemes also have essential effect on stability and stable performance of guidance system due to parasitic loop. To identify characteristics of seeker disturbance rejection rate is useful for determining line of sight rate extraction scheme. Source

Tang R.,Science Research Institute of China North Industries Group Corporation | Liu C.-Y.,China North System Engineering Institute | Zhang J.,Science Research Institute of China North Industries Group Corporation
Binggong Xuebao/Acta Armamentarii

It expounds the relationship between precise attack firepower system and future battlefield reinforcement support system and analyzes some key factors which can affect the firepower system. By analyzing their close relationship, it can be concluded that the development of precise attack firepower system should be focused on, and the coordinate development of multiple systems should also be paid attention to, in order to maximize the combat and operation effectiveness. Source

Zhang W.,Academy of Armored force Engineering | Li W.-W.,China North System Engineering Institute | Ren Z.-H.,Chongqing Communication College | Li Z.-L.,China North System Engineering Institute
Xitong Fangzhen Xuebao / Journal of System Simulation

Path planning based on GIS is a fundamental problem in many applications. It is the main problem affecting the planning time because of the multi-obstacles in field environment. A novel rectangle windowing query method was proposed in order to improve the compute efficiency of collision free test. The method reduces the numbers of obstacles needed to test and speeds the planning process, and is more suitable with the dynamic environment of obstacles changing than the interval tree method. Source

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