Parameter Estimation of the Disk in a Floating Caliper Disk Brake Model with respect to Squeal

Noise from a vehicle is always a concern for any automotive industry looking for passenger comfort. This also holds for the different types of brake noise, in particular for squeal, which is a source of discomfort both to passengers and passers‐by. Intensive research on low frequency squeal (noise between 1‐5 kHz) has been carried out. A model of the floating caliper disk brake has been recently proposed by the authors with the aim to predict the onset of squeal. A flutter type instability resulting from nonconservative restoring forces is assumed to be the reason behind squeal in this model. The problem of validating the model against experimental observation lies in the fact that all the system parameters included in the model, especially the disk, are to be carefully chosen. In this work some parameters of the disk are estimated and a method is suggested to estimate these parameters in a systematic way. For that purpose, the values are to be accurately selected by experiments and modal updating technique. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

矩形片筏基础的挠度分析

工程上对片筏的力学分析，通常采用温克勒地基模型，且假定床基系数是常量。本则认为床基系数是坐标的函数，考虑了具有线性变化床基系数的地基上的片筏，利用伽辽金法求得周边固支片筏在均布荷载作用下的挠度。所得结果颇具一般性且实用价值更高。     

A Stability Analysis of Growth Matrix in Co-operating Enterprises

On the basis of the growth-rate matrix in co-operating enterprises, this study deals with growth stability as well as the possibility of interpolation and extrapolation of a dynamic growth system. This study also suggests an index of growth stability when a new enterprise is introduced: disequilibrium occurs initially, and stability is gradually reached with the passage of time.     

Uncertainty and Sensitivity Analysis of Different Models of Brake Squeal

In this contribution, the brake-squeal phenomenon is investigated using the pin-on-disc setup. The setup is analyzed numerically using the finite element method. The finite element model is evaluated in the time domain, and the vibration mechanism leading to squeal as well as the limit cycles of the vibration are analyzed. Against the background of the high computational costs, it is evaluated to what extent the Hoffmann-Gaul minimal model can reproduce the results of the finite element model. Moreover, as brake squeal is very sensitive with respect to parametric uncertainties, the influence of several parametric uncertainties on the limit cycles is analyzed. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

一类非线性的经济系统控制模型的稳定性分析

用边界比较法讨论了以CE S生产函数作为反馈的定常经济系统控制模型的稳定性,该模型为含有非局部条件的分布参数系统.并且证明了非定常模型的平衡解是全局渐进稳定的.     

A Stability Analysis of Convolution Quadraturea for Abel-Volterra Integral Equations

We investigate the stability properties of numerical methodsfor weakly singular Volterra integral equations of the secondkind. Our theory extends the stability theory of linear multistepmethods for ordinary differential equations. We introduce theconcepts of A-stability, A()-stability etc. for Abel-Volterraequations. The stability region is characterized in terms ofthe weights of the method. It is shown that the order of anA-stable convolution quadrature cannot exceed 2. Further westudy the stability properties of implicit Adam methods, withparticular emphasis on the question of A()-stability.     

钢筋混凝土筏基的挠度分析

本假设筏基为一搁量在三参数地基上的钢筋混凝土薄板，利用伽辽金法求解了受均布荷裁的四边固定的钢筋混凝土板，所得结果颇具广泛性，且清度较高。     

A Non-linear Stability Analysis of the Solidification of a Pure Substance

An investigation is made of the stability of the shape of amoving planar interface between the solid and liquid phasesduring the solidification of a pure substance. The prototypeproblem of controlled two-dimensional growth of a pure solidinto a thermally undercooled liquid bath is considered. Themodel employed postulates diffusion of heat with equal thermaldiffusivities in both phases under the simplifying assumptionsthat these phases are infinite in extent and there is no convectionin the liquid phase. In addition, modified versions of the conservationof heat boundary condition and the Gibbs—Thomson equation,developed by Wollkind and Maurer in earlier work, are imposedat the solid—liquid interface. The main results of ournon-linear analysis, which can be represented in a plot of undercoolingversus solidification speed are that the interface can be unstableto finite amplitude disturbances in some regions where lineartheory predicts stability to infinitesimal disturbances andthat it can exhibit finite amplitude equilibrium for other rangesof parameter values. These results are interpreted in relationto the growth and structure of dendrites.     

转点识别的稳定性

将假设检验的稳定性[1]引入到转点识别中来,考虑了转点识别在正态假设下的稳定性问题.结果显示,转点的N-P检验稳定性不很理想.     

单位圆盘的全纯自同构的推广

单位圆盘的全纯自同构是《复变函数》课程中重要的内容之一,本文给出了单位圆盘的全纯自逆紧映照,其为单位圆盘的全纯自同构的一种推广,可供讲授《复变函数》课程的教师参考.     

两不同部件并联可修复系统指数稳定性分析

研究两不同部件并联可修复系统,运用泛函分析的方法,特别是Banach空间上的线性算子半群理论,证明了严格占优本征值的存在性,并通过分析系统本质谱界经过扰动后的变化,进一步表明在一定的条件下,系统的动态解以指数形式收敛于系统的稳态解.     

Simulation and Analysis of Thermal Fatigue Based on Imperfection Model of Brake Discs

A non-linear FEM model of brake discs of high-speed trains with thermal-mechanical coupling has been established in ANSYS. The simulation and analysis of 3-D transient temperature field and stress field of brake discs have been carried out for the braking process. According to typical imperfections of brake discs, some imperfection models of brake discs have been developed and the thermal stresses of different models are obtained through simulation and analysis. By comparing results of different models, the influence of imperfection parameters, including the position, depth and size, is resulted for the thermal resistance of brake discs. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

复合材料三角形网格加筋圆锥壳体位移型稳定性方程及其总体稳定性分析

本文采用Donnell型扁壳理论,首先利用最小势能原理和广义平均筋条刚度法推导出用位移分量表示的复合材料三角形网格加筋叠层圆锥壳体的稳定性方程,考虑了蒙皮最一般的拉弯与拉扭耦合关系和加筋筋条的偏心效应,并讨论了该方程的基本性质.根据外压实验观察结果,通过选取适当的位移分量表达式,并运用Galerkin法分析了在均布外压作用下复合材料三角形网格加筋叠层圆锥壳体总体稳定性,得到了临界载荷的解析表达式,并对某一类C/E复合材料三角形内网格加筋圆锥壳体的临界外压进行了计算,所得理论值与实验结果很好地吻合.最后,讨论了有关参数对临界载荷的影响.本文所建立的新方程和所得结果对于航空航天结构非常有用.     

Stability Analysis of the Cambridge Ring

A ring of I cells rotates past I queues, carrying customers from their origins to their destinations. The system is modelled as a Markov chain, and the exact ergodicity conditions are given. They are shown to depend on the precise travel lengths distributions, that is, not only on their means. Ergodicity is proven through the stability analysis of the associated fluid limits. The arrivals distributions, which in the ergodicity conditions appear only through their means, are more subtly involved in the fluid limits behaviour, in that they determine the probabilities of random bifurcations that occur infinitely often in a simple system of I=2 queues.     

一类分数阶神经网络模型的稳定性与Hopf分支分析

分析了一类分数阶神经网络的稳定性与Hopf分支问题.基于分数阶稳定性判据,得到了分数阶神经网络模型局部渐近稳定的条件.并以q为分支参数,得到了分数阶系统产生Hopf的条件.最后数值仿真证明了我们的结论.     

货币供给动态调控模型及其稳定性

根据我国货币政策传导机制并结合目前经济金融形势,建立了货币供给系统的一般动态模型,为了便于分析系统的稳定性,在此基础上建立前向离散货币供给系统简化模型并用经济控制论的方法分析了系统的稳定性。     

一类具有Taylor阻尼的Klein-Gordon方程解的稳定性分析

研究了一类具有Taylor阻尼的Klein-Gordon方程解的稳定性.通过对松弛函数及初始值进行适当的限制,首先基于位势井理论,得到了整体解的存在性,然后构造新的能量函数,利用凸函数的性质及扰动能量方法,得到了显式的能量衰减估计.研究过程中弱化了对松弛函数的限制,同时得到了更广泛的能量衰减速率估计.     

Floating Bodies of Equilibrium

A long cylindrical body of circular cross-section and homogeneous density may float in all orientations around the cylinder axis. It is shown that there are also bodies of non-circular cross-sections which may float in any direction. Apart from those found by Auerbach for  ρ= 1/2  , there are one-parameter families of cross-sections for  ρ≠ 1/2  which have a p -fold rotation symmetry. For given p they have this property for   p − 2  different densities ρ. The differential equation governing the non-circular boundary curve is derived. Its solution is expressed in terms of an elliptic integral.