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Zhan J.-C.,Beijing Special Engineering Design Institute | Zhan J.-C.,China Institute of Technology | Guo X.-S.,China Institute of Technology | Fei Y.-F.,Beijing Special Engineering Design Institute | Chang Z.-Y.,Beijing Special Engineering Design Institute
Geotechnical and Geological Engineering | Year: 2013

Classical bearing capacity expressions can not afford variant engineering requests, since they were deducted under hypotheses of strip footing on homogeneous soil. An often met case was taken into account that circular footing on two-layered ground, which has firm crust and weak subgrade. Weighted method and layered method were used in capacity deduction, respectively. The former counts layered soils as single layer of weighted structure and material parameters. But it is restricted to conditions with close strength to each layer. The latter is preferred in engineering calculation, which regards the whole bearing capacity as subgrade's capacity under the influence of the upper layer. Thus the issue is transformed to K. Terzaghi model plus stress reduction and dispersion effects. At last, the expressions gained from both methods and finite element analysis (FEA) were used in an example calculation, respectively. It approves layered calculating method and suggests the corresponding security coefficient based on elastoplastic FEA results. © 2013 Springer Science+Business Media Dordrecht.


Hong X.,Beijing University of Posts and Telecommunications | Wu J.,Beijing University of Posts and Telecommunications | Zuo C.,Beijing Special Engineering Design Institute | Liu F.,Beijing University of Posts and Telecommunications | And 2 more authors.
Applied Optics | Year: 2011

A distributed fiber optic vibration sensor is described, in which two Michelson interferometers are used as phase detectors and two 3 × 3 couplers are deployed to demodulate the time-varying phase change caused by vibration. The two interferometers are separated by four wavelength division multiplexers. The position of the vibration is obtained by signal correlation, which can be used as a perimeter security sensor to locate the intruder. The experimental results with a 4012mfiber sensor are discussed. © 2011 Optical Society of America.


Zhang G.Y.,Beijing Special Engineering Design Institute | Xu M.L.,National University of Defense Technology | Zhang R.Q.,National University of Defense Technology | Tang W.H.,National University of Defense Technology
World Academy of Science, Engineering and Technology | Year: 2011

MOC (method of cell) is a new method of investigating wave propagating in material with periodic microstructure, and can reflect the effect of microstructure. Wave propagation in periodically laminated medium consisting of linearly elastic layers can be treated as a special application of this method. In this paper, it was used to simulate the dynamic response of carbon-phenolic to impulsive loading under certain boundary conditions. From the comparison between the results obtained from this method and the exact results based on propagator matrix theory, excellent agreement is achieved. Conclusion can be made that the oscillation periodicity is decided by the thickness of sub-cells. In the end, the NHDMOC method, which permits studying stress wave propagation with one dimensional strain, was applied to study the one-dimensional stress wave propagation. In this paper, the ZWT nonlinear visco-elastic constitutive relationship with 7 parameters, NHDMOC, and corresponding equations were deduced. The equations were verified, comparing the elastic stress wave propagation in SHPB with, respectively, the elastic and the visco-elastic bar. Finally the dispersion and attenuation of stress wave in SHPB with visco-elastic bar was studied.


Liu Q.-W.,CAS Institute of Software | Liu Q.-W.,University of Chinese Academy of Sciences | Cao Z.-S.,Beijing Special Engineering Design Institute | Zheng C.-W.,CAS Institute of Software | Hu X.-H.,CAS Institute of Software
Yuhang Xuebao/Journal of Astronautics | Year: 2011

A new method using image series of monocular optical imaging system on motion platform for spacecraft orbit determination is developed in the absence of position or velocity information of target spacecraft. Through analysis of characteristics about the imaging system and space relation of the imaging system and the spacecraft, the concept on the real average angular velocity and the apparent average angular velocity is presented to design an equation in order to estimate slope distance of the imaging system according to longitude and latitude data derived from image series and to calculate spacecraft initial state parameters. This method offers an approach for orbit determination with series image from the monocular optical imaging system by coping with the problem to calculate the longitude and latitude according to image series and then to estimate the slope distance. Finally a simulation instance of a GEO satellite is adopted to validate this method.


Qi J.,National University of Defense Technology | Jiang P.,National University of Defense Technology | Guo B.,National University of Defense Technology | Wang D.,Beijing Special Engineering Design Institute
QR2MSE 2013 - Proceedings of 2013 International Conference on Quality, Reliability, Risk, Maintenance, and Safety Engineering | Year: 2013

For long-wait-short-run equipment, it is in the standby state with very short operating time during its lifetime. The performance degradation of this equipment depends on not only the accumulative operating time, but also the accumulative non-operating time. In this paper, the reliability model of the long-wait-short-run equipment is established based on Gamma process in which both the accumulative operating time and the accumulative non-operating time are treated as independent variables. The method to evaluate the reliability is also proposed. Finally, a numerical experiment is given and the result shows that the proposed method is proper to evaluate the reliability of the long-wait-short-run equipment. © 2013 IEEE.


Xu M.L.,National University of Defense Technology | Zhang G.Y.,National University of Defense Technology | Zhang G.Y.,Beijing Special Engineering Design Institute | Zhang R.Q.,National University of Defense Technology
Applied Mechanics and Materials | Year: 2014

In this paper the NHDMOC method which succeeded in studying stress wave propagation with one dimensional strain was applied to study the one-dimensional stress wave propagation. In this paper, the ZWT nonlinear visco-elastic constitutive relationship with 7 parameters to NHDMOC, and corresponding equations were deduced The equations was verified from the comparison of elastic stress wave propagation in SHPB with elastic bar and visco-elastic bar respectively. Finally the dispersion and attenuation of stress wave in SHPB with visco-elastic bar was studied. © (2014) Trans Tech Publications, Switzerland.


Li Z.,Chinese Institute of Crustal Dynamics | Wang J.,Chinese Institute of Crustal Dynamics | Liu L.,Beijing Special Engineering Design Institute
2010 International Conference on E-Product E-Service and E-Entertainment, ICEEE2010 | Year: 2010

Voice over Internet Protocol (VoIP) over a wireless local area network (WLAN) is poised to become an important Internet application. However, unacceptable VoIP performance in the presence of coexisting traffic from other applications is still one of the major problems standing in its development way. For this point, in this paper, a novel adapted adjustment packet segmentation method is proposed to promote the performance of VoIP which do not influence non-real-time application much. In this method we use the channel utilization to decide the segmentation's factor. This method is verified through simulations. ©2010 IEEE.

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