齿轮－转子－滑动轴承系统时变非线性动力特性研究

本文应用求周期解的数值计算方法─—打靶法和判定周期解稳定性的Ｆｌｏｑｕｅｔ乘子研究了齿轮－转子－滑动轴承系统中齿轮啮合时变刚度，滑动轴承非线性特性对转子系统不平衡响应和失稳的影响，并比较了平衡位置失稳和不平衡响应周期解失稳，以及按双轴计算与单轴计算结果的差别，为工程设计理论计算提供基础。     

Nonlinear analysis of near-wall turbulence time series

We present the results of the nonlinear analysis of a near-wall turbulence signal, measured using a Laser Doppler Anemometer. Despite being preliminary in part, the results highlight some interesting aspects of the dynamics of coherent structures. Careful reconstruction of the dynamics from the scalar time series highlight particular phases of the bursting cycle, corresponding to the VITA detections, immersed in the overall high-dimension dynamics: the possibility to distinguish these trajectories in the embedding space provides indications for conditional sampling techniques on the reconstructed attractor. The application of nonlinear prediction to a system of high-dimension produces forecasts of rapidly decreasing quality over time, with no consequences for practical applications. Much more interesting instead is the analysis of the forecast errors for very short forecast intervals, where we observed a greater difficulty to predict the beginning of coherent structure instability probably due to the quasi-random forcing of the outer flow.     

DYNAMICAL FORMATION OF CAVITY FOR COMPOSED THERMAL HYPERELASTIC SPHERES IN NONUNIFORM TEMPERATURE FIELDS

Dynamical formation and growth of cavity in a sphere composed of two incompressible thermal-hyperelastic Gent-Thomas materials were discussed under the case of a non-uniform temperature field and the surface dead loading. The mathematical model was first presented based on the dynamical theory of finite deformations. An exact differential relation between the void radius and surface load was obtained by using the variable transformation method. By numerical computation, critical loads and cavitation growth curves were obtained for different temperatures. The influence of the temperature and material parameters of the composed sphere on the void formation and growth was considered and compared with those for static analysis. The results show that the cavity occurs suddenly with a finite radius and its evolvement with time displays a non-linear periodic vibration and that the critical load decreases with the increase of temperature and also the dynamical critical load is lower than the static critical load under the same conditions.     

LINEAR AND NONLINEAR DIELECTRIC PROPERTIES OF PARTICULATE COMPOSITES AT FINITE CONCENTRATION

An analytical method was proposed dielectric properties for particulate composites. to calculate effective linear and nonlinear The method is based on an approximate solution of two-particle interaction problem, and it can be applied to relatively high volume concentration of particles （up to 50%）. Nonlinear dielectric property was also examined by means of secant method. It is found that for low applied electric filed the proposed method is close to Stroud and Hui＇s method and for high applied electric filed it is close to Yu＇s method.     

NUMERICAL METHOD AND APPLICATION FOR THREEDIMENSIONAL NONLINEAR SYSTEM OF DYNAMICS OF FLUIDS IN POROUS MEDIA

For the system of multilayer dynamics of fluids in porous media, the second order upwind finite difference fractional steps schemes applicable to parallel arithmetic are put forward. Some techniques, such as calculus of variations, energy method, multiplicative commutation rule of difference operators, decomposition of high order difference operators and prior estimates are adopted. Optimal order estimates are derived to determine the error in the second order approximate solution. These methods have already been applied to the numerical simulation of migration-accumulation of oil resources.     

基于神经网络的误差补偿滤波器在陀螺漂移误差模型辨识中的应用

用神经网络补偿非线性卡尔曼滤波器的状态估计误差，并将其用于陀螺漂移误差模型的参数辨识中，仿真结果表明该方法的有效性。     

无侧移半刚性连接组合框架的稳定分析:(Ⅰ)柱的有效长度系数方程

本文基于钢结构设计规范GB50017-2003,利用三柱子框架模型,考虑了连接的非线性弯矩-转角关系和楼板组合效应的影响,推导了无侧移半刚性连接组合框架柱的有效长度系数方程式,同时考虑了梁端和柱远端不同约束情况对有效长度系数的影响。另外,分析了GB50017规范附录D表D-1求解的精确性。研究表明,当柱远端刚接时,推导的方程式类似于GB50017规范附录D表D-1给出的无侧移刚接框架柱的有效长度系数计算公式;对于三柱子框架模型,当柱远端铰接时,用GB50017规范附录D表D-1得到的有效长度系数设计柱是不安全的,但最大误差只有11%。     

非线性问题严格互补极点－鞍点定理

本文给出两个具有新的非线性型式问题的严格互补极点－鞍点定理，同时论述了建议的二次变分－凸分析方法的一般性和有效性。其一是旋转叶轮问题，通过引进周期性自由面变量，揭示了隐含的一类对偶变分原理，从而给出了可能存在的全部互补原理。其二是带转动变量的非Ｋ－Ｌ壳体，具有超出常规的几何非线性性质，目前只知道使用这里的方法可以建立互补原理。     

圆柱壳的非线性自由振动分析

本文分析了各向同性封闭圆柱壳的非线性自由振动。文中采用经典的非线性弹性力学方法推导了圆柱壳的大振幅运动方程,这些方程的静态形式与冯·卡门的板理论方程具有同样的精度。文中讨论了四种基本振动模态,并且还以数学公式的形式给出了一般的最终结果,一些例子以曲线给出结果,并进行了比较。结果还表明线性振动可以作为非线性振动的一种特例。