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Inhomogeneity problem with a sliding interface under remote shearing stress

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中国科学：物理学、力学、天文学英文版 2012年第11期55卷 2122-2127页

作者： ZHAO YingTao GAO Yang WANG MinZhong department of mechanics School of Aerospace EngineeringBeijing Institute of TechnologyBeijing 100081China College of Science China Agricultural UniversityP.O.Box 74Beijing 100083China state key laboratory for turbulence and complex systems and department of mechanics and aerospace engineering College of EngineeringPeking UniversityBeijing 100871China

The problem of an ellipsoidal inhomogeneity embedded in an infinitely extended elastic medium with sliding interfaces is *** exact solution is presented for such an inhomogeneous system that is subject to remote uniform shearing *** the elastic inclusion and matrix are considered isotropic with a separate elastic *** on Luré's approach to solving ellipsoidal cavity problems through Lamé functions,several harmonic functions are introduced for Papkovich-Neuber displacement *** displacement fields inside and outside the ellipsoidal inclusion are obtained explicitly,and the stress field in the whole domain is consequently determined.

关键词：非均匀性滑动界面远程剪应力椭球夹杂弹性介质非均匀系统土地使用权

Exponential attitude and gyro-bias estimation on the Special orthogonal group SO（3）

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Exponential attitude and gyro-bias estimation on the Special...

THE TENSOR DENOTATION OF BELTRAMI SPHERICAL VORTICES AND THEIR SYMMETRY ANALYSIS

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作者： PENG Xiuhui SUN Junyong GENG Zhiyong The state key laboratory for turbulence and complex systems department of mechanics and engineering Science College of EngineeringPeking University

ISBN: (纸本)9781538629185

This paper considers a nonlinear attitude estimator to estimate the attitude and gyro-bias exponentially for rigid body whose kinematics is evolved on the Special orthogonal group SO（3）, which can describe the attitude globally and *** to the asymptotic stabilities which are presented in the previous literature, the estimator presented in this paper has exponential convergence. The exponential stability analysis is demonstrated by singular perturbation method which divide the closed loop system into fast system and slow system. The results can be apply to the vehicles which are equipped with the low-cost inertial measurement unit（IMU） such as gyroscope. Finally, the theoretical results are verified through a numerical simulation.

关键词： Attitude estimator Gyro-bias Special orthogonal group SO(3) Exponential stability Singular perturbation method

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Applied Mathematics and mechanics(English Edition) 2002年第1期23卷 13-17页

作者： HUANG Yong-nian(黄永年) HU Xin(胡欣) department of mechanics and engineering Science State Key Laboratory for Turbulence Research Peking University Beijing 100871 P R China Department of Mechanics and Engineering Science State Key Laboratory for Turbulence Research Peking University Beijing 100871 P R China

One kind of tensor denotation of nth Beltrami axisymmetric and nonaxisymmetric spherical vortices, their classification and symmetries were discussed. Chaotic Phenomena will occur in the dynamic system of the nonaxisymmetric Beltrami spherical vortices. From these aspects, it is shown that the tensor denotation has more meaningful characters and nonaxisymmetric Beltrami shperical vortices are various and very complex.

关键词： Beltrami flow tensor denotation symmetry chaotic phenomena

Distributed adaptive attitude synchronization of multiple spacecraft

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Science China(Technological Sciences) 2011年第8期54卷 1992-1998页

作者： LI ZhongKui DUAN ZhiSheng School of Automation Beijing Institute of Technology Beijing 100081 China state key Lab. for turbulence and complex systems Department of Mechanics and Aerospace Engineering College of Engineering Peking University Beijing 100871 China

This paper addresses the distributed attitude synchronization problem of multiple spacecraft with unknown inertia matrices. Two distributed adaptive controllers are proposed for the cases with and without a virtual leader to which a time-varying reference attitude is assigned. The first controller achieves attitude synchronization for a group of spacecraft with a leaderless communication topology having a directed spanning tree. The second controller guarantees that all spacecraft track the reference attitude if the virtual leader has a directed path to all other spacecraft. Simulation examples are presented to illustrate the effectiveness of the results.

关键词：自适应控制器同步问题航天器分布式惯性矩阵时间变化拓扑结构领导人

Average Range and Network Synchronizability

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Communications in Theoretical Physics 2010年第1期53卷 115-120页

作者：刘超李嵘段志生陈关荣 department of Applied Mathematics Shanghai University of Finance and Economics department of Applied Mathematics Shanghai Finance University state key laboratory for turbulence and complex systems Department of Mechanics and Aerospace Engineering College of Engineering Peking University department of Electronic engineering City University of Hong Kong

网络 synchronizability 上的一个网络的结构的性质的影响被介绍边的平均范围的一个新概念学习。为小世界、没有规模的网络，网络与的 synchronizability 上的平均范围的效果跳或无界的同步区域通过数字模拟被说明。在平均范围，范围分... 详细信息

网络 synchronizability 上的一个网络的结构的性质的影响被介绍边的平均范围的一个新概念学习。为小世界、没有规模的网络，网络与的 synchronizability 上的平均范围的效果跳或无界的同步区域通过数字模拟被说明。在平均范围，范围分发，平均距离，和最大的 betweenness 之间的关系也被探索，分别地揭示小世界、没有规模的网络的网络 synchronizability 上的这些因素的效果。

关键词：平均距离网络结构同步性能无标度网络网络同步数值模拟同步效应无界区域

Velocity overshoot of start-up flow for a Maxwell fluid in a porous half-space

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Chinese Physics B 2006年第11期15卷 2644-2650页

作者：谭文长 state key laboratory of turbulence and complex systems Department of Mechanics and Aerospace Engineering College of Engineering Peking University Beijing 100871 China

Stokes＇ first problem has been investigated for a Maxwell fluid in a porous half-space for gaining insight into the effect of viscoelasticity on the start-up flow in a porous medium. An exact solution was obtained by using the Fourier sine transform. It was found that at large values of the relaxation time the velocity overshoot occurs obviously and the system exhibits viscoelastic behaviours. On the other hand, for short relaxation time the velocity overshoot disappears and the system exhibits viscous behaviours. A critical value of the relaxation time was obtained for the emergence of the velocity overshoot. Furthermore, it was found that the velocity overshoot is caused by both the viscoelasticity of the Maxwell fluid and the Darcy resistance resulting from the structure of the micropore in the porous medium.

关键词： Maxwell fluid porous media velocity overshoot

Average Synchronization and Temporal Order in a Noisy Neuronal Network with Coupling Delay

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Chinese Physics Letters 2007年第10期24卷 2759-2761页

作者：王青云段志生陆启韶 state key laboratory for turbulence and complex systems Department of Mechanics and Aerospace Engineering College of Engineering Peking University Beijing 100871 department of Statistics and Mathematics Inner Mongolia Finance and Economics College Huhhot 010051 School of Science Beijing University of Aeronautics and Astronautics Beijing 100083

Average synchronization and temporal order characterized by the rate of firing are studied in a spatially extended network system with the coupling time delay, which is locally modelled by a two-dimensional Rulkov map neuron. It is shown that there exists an optimal noise level, where average synchronization and temporal order are maximum irrespective of the coupling time delay. Furthermore, it is found that temporal order is weakened when the coupling time delay appears. However, the coupling time delay has a twofold effect on average synchronization, one associated with its increase, the other with its decrease. This clearly manifests that random perturbations and time delay play a complementary role in synchronization and temporal order.

关键词： coated conductor buffer layer self-epitaxy CeO2

A novel static shape-adjustment technique for planar phased-array satellite antennas

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Acta Mechanica Sinica 2018年第6期34卷 1145-1155页

作者： Ji-Yang Zhou Guang-Yu Lu Guo-Ping Cai Guang-Qiang Fang Liang-Liang Lv Jun-Wei Shi department of engineering mechanics State Key Laboratory of Ocean EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Institute of aerospace system engineering Shanghai 201109China

Planar phased-array satellite antennas deform when subjected to external disturbances such as thermal gradients or slewing *** distortion can degrade the coherence of the antenna and must therefore be eliminated to maintain *** support planar phased-array satellite antennas,a truss with diagonal cables is often applied,generally pretensioned to improve the stiffness of the antenna and maintain the integrity of the structure.A new technique is proposed herein,using the diagonal cables as the actuators for static shape adjustment of the planar phased-array satellite *** this technique,the diagonal cables are not pretensioned;instead,they are slack when the deformation of the antenna is *** using this technique,there is no need to add redundant control devices,improving the reliability and reducing the mass of the *** finite element method is used to establish a structural model for the satellite antenna,then a method is introduced to select proper diagonal cables and determine the corresponding *** simulations of a simplified two-bay satellite antenna are first carried out to validate the proposed ***,a simplified 18-bay antenna is also studied,because spaceborne satellite antennas have inevitably tended to be large in recent *** numerical simulation results show that the proposed technique can be effectively used to adjust the static shape of planar phased-array satellite antennas,achieving high precision.

关键词： Planar phased-array satellite antenna Static shape adjustment Diagonal cables Active control

Piezoelectric Actuator Placement Optimization and Active Vibration Control of a Membrane Structure

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Acta Mechanica Solida Sinica 2018年第1期31卷 66-79页

作者： Xiang Liu Guoping Cai Fujun Peng Hua Zhang department of engineering mechanics State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200240 China Shanghai Institute of aerospace system engineering Shanghai 201109 China

The placement optimization of piezoelectric actuators and active vibration control of a membrane structure are studied in this paper. The classical linear quadratic regulator con- trollers are designed to suppress the unwanted vibration. Simulation results indicate that the optimal locations of piezoelectric actuators are affected deeply by the additional mass and stiff- ness of actuators, the computational efficiency of particle swarm optimizer is higher than that of genetic algorithm for this particular problem, and the control performance of optimally placed actuators is better than that of non-optimally placed actuators.

关键词： Membrane Smart structure Vibration control