The China Academy of Launch Vehicle Technology is the premier space launch vehicle manufacturer in China and one of the major launch service providers in the world. CALT is a subordinate of the larger China Aerospace Science and Technology Corporation . It was established in 1957 and is headquartered in the southern suburbs of Beijing.CALT is state-owned but is not actively state managed; its organization and orientation are comparable to Western defence and space contractors. Its major contribution to Chinese launch capability has been the manufacture of the Long March family of rockets. CALT has 27 000 employees and at least 13 research facilities. Wikipedia.
Zhi W.,Dalian University of Technology |
Qiang Q.,China Academy of Launch Vehicle Technology |
Zhanjun W.,Dalian University of Technology |
Guodong S.,Dalian University of Technology
Materials and Design | Year: 2011
In the present work, the thermal shock resistance of the ZrB2-SiC-ZrC ceramic was estimated by the water quenching method and the flexural strength of the quenched specimen was measured. The measured critical temperature difference of the ZrB2-SiC-ZrC ceramic was significantly greater than that of the ZrB2-15vol.% SiC ceramic. The improvement in thermal shock resistance was attributed to its higher fracture toughness (6.7MPam1/2) and lower flexural strength (526MPa) relative to the ZrB2-15vol.% SiC ceramic (4.1MPam1/2 and 795MPa) based on Griffith fracture criterion. Furthermore, the temperature and thermal stress distributions in the specimen during instantaneous water quenching were simulated by Finite element analysis. © 2011 Elsevier Ltd.
Xu B.,Northwestern Polytechnical University |
Xu B.,Nanyang Technological University |
Huang X.,China Academy of Launch Vehicle Technology |
Wang D.,Nanyang Technological University |
Sun F.,Tsinghua University
Asian Journal of Control | Year: 2014
In this paper, the robust adaptive controller is investigated for the longitudinal dynamics of a generic hypersonic flight vehicle. The proposed methodology addresses the issue of controller design and stability analysis with respect to parametric model uncertainty and input saturations for the control-oriented model. The velocity and attitude subsystems are transformed into the linearly parameterized form. Based on the parameter projection estimation, the dynamic inverse control is proposed via the back-stepping scheme. In order to avoid the problem of "explosion of complexity," by introducing a first-order filtering of the synthetic input at each step, the dynamic surface control is designed. The closed-loop system achieves uniform ultimately bounded stability. The compensation design is employed when the input saturations occur. Simulation results show that the proposed approach achieves good tracking performance. © 2013 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.
Wang C.,Beihang University |
Qiu Z.,Beihang University |
Wu D.,China Academy of Launch Vehicle Technology
Science China: Physics, Mechanics and Astronomy | Year: 2014
Based on the combination of stochastic mathematics and conventional finite difference method, a new numerical computing technique named stochastic finite difference for solving heat conduction problems with random physical parameters, initial and boundary conditions is discussed. Begin with the analysis of steady-state heat conduction problems, difference discrete equations with random parameters are established, and then the computing formulas for the mean value and variance of temperature field are derived by the second-order stochastic parameter perturbation method. Subsequently, the proposed random model and method are extended to the field of transient heat conduction and the new analysis theory of stability applicable to stochastic difference schemes is developed. The layer-by-layer recursive equations for the first two probabilistic moments of the transient temperature field at different time points are quickly obtained and easily solved by programming. Finally, by comparing the results with traditional Monte Carlo simulation, two numerical examples are given to demonstrate the feasibility and effectiveness of the presented method for solving both steady-state and transient heat conduction problems. © 2014 Science China Press and Springer-Verlag Berlin Heidelberg.
Zhao J.,China Academy of Launch Vehicle Technology
Journal of Thermal Science | Year: 2015
In this paper the liquid argon nanojet break-up phenomenon was studied using the molecular dynamics method. The effects of temperature, nozzle diameter and body force on the nanojet break-up length and time were simulated. Meanwhile, the particle size, wave length and the frequency of the disturbance were compared with the results of linear stability analysis. The results showed that even though the fluid becomes discontinuous, the traditional linear stability analysis can be used to make a rough calculation of the nanojet break-up. © 2015, Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag Berlin Heidelberg.
Wu S.-B.,Nanjing University of Science and Technology |
Wu S.-B.,China Academy of Launch Vehicle Technology |
Zhang D.-G.,Nanjing University of Science and Technology
Zhendong Gongcheng Xuebao/Journal of Vibration Engineering | Year: 2011
The rigid-flexible coupling dynamic properties of a hub-flexible beam system undergoing free large overall plane motions are studied. The longitudinal deformation and the transverse deformation of flexible beam are considered and the coupling term of the deformation which is caused by transverse deformation is included in the expression of longitudinal deformation. The governing equations of motion for this system are established using assumed mode method and Lagrange's equations. The dynamics of the system undergoing rotation or translation or plane motion are simulated, and the emphasis is the rigid-flexible coupling dynamic properties of the system undergoing translation. The coupling dynamics of the system under external excitations is simulated firstly. And secondly the influence of translation on the small deformation motion of flexible beam is analyzed. It is shown that the traditional zero-order approximation model can not describe the coupling effect between the translation and the small deformation motion of flexible beam. Also, both phenomenon of dynamic stiffening and dynamic softening can occur in the beam when the system undergoes different acceleration of translation.