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GLOBAL STABILITY IN HOPFIELD NEURAL NETWORKS WITH DISTRIBUTED TIME DELAYS

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Journal of Electronics(china) 2001年第2期18卷 147-154页

作者： Zhang Jiye Wu Pingbo Dai Huanyun (traction power national laboratory, southwest jiaotong university, chengdu 610031) traction power national laboratory Southwest Jiaotong UniversityChengdu 610031

In this paper, without assuming the boundedness, monotonicity and differentiability of the activation functions, the conditions ensuring existence, uniqueness, and global asymptotical stability of the equilibrium point of Hopfield neural network models with distributed time delays are studied. Using M-matrix theory and constructing proper Liapunov functionals, the sufficient conditions for global asymptotic stability are obtained.

关键词： Distributed time delays Neural network Global asymptotic stability M-matrix

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车辆横向半主动悬挂的神经网络自适应控制

铁道学报 2002年第4期24卷 34-37页

作者：王月明曾京西南交通大学机械工程学院四川成都610031 西南交通大学牵引动力国家重点实验室四川成都610031

分析了车辆半主动悬挂模型的非线性特性 ,提出了采用神经网络的半主动悬挂自适应控制模型 ,设计了神经网络辨识器和控制器 ,采用专门算法修正控制器网络权值。仿真计算表明。

关键词：横向半主动悬挂神经网络自适应控制列车

利用半实物半虚拟试验方法研究接触网参数对弓网接触力的影响

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铁道学报 2004年第1期26卷 33-39页

作者：梅桂明张卫华西南交通大学牵引动力国家重点实验室四川成都610031

在对弓网关系研究方法分析比较的基础上 ,采用了最新、最接近实际物理状态的半实物半虚拟混合模拟试验方法。介绍了混合模拟的基本原理及试验流程 ,进一步推导了接触网动力学微分方程 ,并以国内简单链形悬挂接触网和德国DSA3 80高速受... 详细信息

在对弓网关系研究方法分析比较的基础上 ,采用了最新、最接近实际物理状态的半实物半虚拟混合模拟试验方法。介绍了混合模拟的基本原理及试验流程 ,进一步推导了接触网动力学微分方程 ,并以国内简单链形悬挂接触网和德国DSA3 80高速受电弓为研究对象 ,分析研究了接触网参数 (跨距、结构高度、接触线张力、承力索张力、接触线线密度、承力索线密度、接触线弛度、接触线表面不平顺等 )对弓网接触力的影响 ,以“接触力最小值”最大、“接触力最大值”最小及“均方根值”最小作为受流质量的评定标准。

关键词：接触网参数弓网接触力半实物半虚拟方法动力学受流

Analysis of vibration reduction characteristics and applicability of steel-spring floating-slab track

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Journal of Modern Transportation 2011年第4期19卷 215-222页

作者： Wanming ZHAI Peng XU Kai WEI traction power State Key laboratory Southwest Jiaotong University Chengdu 610031 China

A coupled dynamics computation model for metro vehicles, along with a steel-spring floating-slab track, is developed based on the theory of vehicle-track coupled dynamics. Using the developed model, the influences of the thickness, length and mass of floating-slab, spring rate and its arrangement space, running speed, etc. on the time and frequency domain characteristics of steel-spring fulcrum force are analyzed. The applicability of steel-spring floatingslab track is discussed through two integrated example cases of metro and buildings possessing distinct natural vibra- tion characteristics. It is concluded that, it is quite significant, in the optimization modular design of the parameters of steel-spring floating-slab track, to take the matching relationship of both the amplitude-frequency characteristics of steel-spring fulcrum force and natural vibration characteristics of integrated structures into comprehensive consideration. In this way the expensive steel-spring floating-slab track can be economically and efficiently utilized according to the site condition, and at the same time, the economic losses and bad social impact resulted from the resonance during usage of steel-spring floating-slab track can be avoided.

关键词： integrated structures natural vibration characteristics subway vibration steel-spring floating-slab track steel-spring fulcrum force frequency spectrum analysis

An improved algorithm for fluid-structure interaction of high-speed trains under crosswind

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Journal of Modern Transportation 2011年第2期19卷 75-81页

作者： Tian LI Jiye ZHANG Weihua ZHANG traction power State Key laboratory Southwest Jiaotong University Chengdu 610031 China

Based on the train-track coupling dynamics and high-speed train aerodynamics, this paper deals with an improved algorithm for fluid-structure interaction of high-speed trains. In the algorithm, the data communication between fluid solver and structure solver is avoided by inserting the program of train-track coupling dynamics into fluid dynamics program, and the relaxation factor concerning the load boundary of the fluid-structure interface is introduced to improve the fluctuation and convergence of aerodynamic forces. With this method, the fluid-structure dynamics of a highspeed train are simulated under the condition that the velocity of crosswind is 13.8 m/s and the train speed is 350 km/h. When the relaxation factor equals 0.5, the fluctuation of aerodynamic forces is lower and its convergence is faster than in other cases. The side force and lateral displacement of the head train are compared between off-line simulation and co-simulation. Simulation results show that the fluid-structure interaction has a significant influence on the aerodynam- ics and attitude of the head train under crosswind conditions. In addition, the security indexes of the head train worsen after the fluid-structure interaction calculation. Therefore, the fluid-structure interaction calculation is necessary for high-speed trains.

关键词： high-speed train fluid-structure interaction crosswind aerodynamics relaxation factor

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车辆稳态曲线通过性能的延续算法

铁道学报 2002年第2期24卷 30-34页

作者：吕可维曾京张卫华西南交通大学牵引动力国家重点实验室四川成都610031

应用 DERPAR延续算法克服了 Newton- Raphson迭代法的局部收敛域过小的问题 ,使对初值选取的要求得以放宽。应用该算法可研究车辆稳态曲线通过性能随参数延续变化的问题。

关键词：车辆稳态曲线通过延续算法

An Efficient and Accurate Numerical Algorithm for Multi－Dimensional Modeling of Casting Solidification，Part Ⅱ：Combination of FEM and FDM

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Journal of Modern Transportation 1994年第2期11卷 152-166页

作者： Jin Xuesong(national traction power laboratory), southwest jiaotong university,chengdu 610031, china Tsai Hailung(university of Missouri-Rolla), Rolla, Mo. 65401, USA national traction power laboratory Southwest Jiaotong University Chengdu 610031 China university of Missouri-Rolla RollaMo. 65401 USA

This paper is a continuation of Ref. [1]. It employs frist-order accurateTaylor-Galerkin-based finite element approach for casting solidification. Theapproach is based on expressing the finite-difference approximation of thetransient time derivative of temperature, while the expressions of the governingequations are discretized in space via the classical Galerkin scheme using finite-element formulations. The detailed technique is reported in this study. Severalcasting solidification examples are solved to demonstrate the excellentagreements in comparison with the results obtained by using the control volumemethod, and to show the availability of combination of the finite elementmethod and the finite difference method in multi-dimensional modeling ofcasting solidification.

关键词： casting mold soidification Galerkin schemem finite element method finitedifference method

GLOBAL EXPONENTIAL STABILITY IN DELAYED HOPFIELD NEURAL NETWORK MODELS

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GLOBAL EXPONENTIAL STABILITY IN DELAYED HOPFIELD NEURAL NETW...

Size-dependent thermomechanical vibration characteristics of rotating pre-twisted functionally graded shear deformable microbeams

2001亚太振动会议

作者： LU Li ZHANG Jiye YANG YirenDepartment of Applied Mechanics and Engineering southwest jiaotong university chengdu 610031 china traction power national laboratory southwest jiaotong university chengdu 610031 china

＜正＞ The global exponential Stability of delayed Hopfieldneural network models are studied. Without assuming themonotonicity and differentiability of the activationfunctions, by utilizing matrix theory,Liapunovfunctionals are constructed and employed to establishsufficient conditions for global exponential stabilityindependent of the delays.

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1015-1032页

作者： Songye JIN Bo ZHANG Wuyuan ZHANG Yuxing WANG Huoming SHEN jing WANG Juan liu School of Mechanics and Aerospace Engineering Southwest Jiaotong UniversityChengdu 610031China School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China School of Mechanical and Electrical Engineering Southwest Petroleum UniversityChengdu 610500China

A three-dimensional(3D)thermomechanical vibration model is developed for rotating pre-twisted functionally graded(FG)microbeams according to the refined shear deformation theory(RSDT)and the modified couple stress theory(MCST).The material properties are assumed to follow a power-law distribution along the chordwise *** model introduces one axial stretching variable and four transverse deflection variables including two pure bending components and two pure shear *** complex modal analysis and assumed mode methods are used to solve the governing equations of motion under different boundary conditions(BCs).Several examples are presented to verify the effectiveness of the developed *** coupling the slenderness ratio,gradient index,rotation speed,and size effect with the pre-twisted angle,the effects of these factors on the thermomechanical vibration of the microbeam with different BCs are *** is found that with the increase in the pre-twisted angle,the critical slenderness ratio and gradient index corresponding to the thermal instability of the microbeam increase,while the critical material length scale parameter(MLSP)and rotation speed *** sensitivity of the fundamental frequency to temperature increases with the increasing slenderness ratio and gradient index,and decreases with the other increasing ***,the size effect can suppress the dynamic stiffening effect and enhance the Coriolis ***,the mode transition is quantitatively demonstrated by a modal assurance criterion(MAC).

关键词： thermomechanical vibration rotating pre-twisted functionally graded(FG)microbeam refined shear deformation theory(RSDT) modified couple stress theory(MCST) modal assurance criterion(MAC)