应用优化技术计算船舶斜浪中的扭矩外力

 从实用角度出发，应用优化技术，确定船舶斜浪中的平衡浮 态，在传统方法基础上更接近实际状态. 提出了一种船舶斜置于波 浪上的外力计算方法，编制了计算机程序. 另外，特别针对大开口 船舶其剖面扭心在基线以下的特点，计及了左右舷不对称横向力对 扭矩的贡献.     

GENERAL SOLUTION OF THE OVERALL BENDING OF FLEXIBLE CIRCULAR RING SHELLS WITH MODERATELY SLENDER RATIO AND APPLICATIONS TO THE BELLOWS (Ⅳ)-CALCULATION FOR U-SHAPED BELLOWS

This is one of the applications of Part (I), in which the angular stiffness, and the corresponding stress distributions of U-shaped bellows were discussed. The bellows was divided into protruding sections, concave sections and ring plates for the calculation that the general solution (I) with its reduced form to ring plates were used respectively, but the continuity of the surface stresses and the meridian rotations at each joint of the sections were entirely satisfied. The resent results were compared with those of the slender ring shell solution proposed earlier by the authors, the standards of the Expansion Joint Manufacturers Association (EJMA), the experiment and the finite element method. It is shown that the governing equation and the general solution (I) are very effective. Contributed by HUANG Qian Biography: ZHU Wei-ping (1962-)     

基于复模态的控制力矩陀螺配置优化

由于陀螺耦合效应,系统动力学方程的特征值和特征向量皆为复数形式,不便于进行控制力矩陀螺的配置优化和控制律设计。本文基于复模态理论,构造出一种实数域上的伪模态矩阵,从而实现方程解耦。综合考虑结构模态、控制输入能量和传感器接收能量的复合优化准则,获得了控制力矩陀螺的最优配置。结果表明,采用线性二次型最优控制,能够快速将结构的响应振幅降至5%以内,验证了使用伪模态矩阵进行方程解耦的可行性及控制的有效性。     

二阶矩两相湍流模型中的改进算法

建立了融合SIMPLEC算法在内的考虑了浓度修正影响的颗粒压力修正方程。提出了二阶矩湍流模型下考虑浓度修正值影响的两相湍流流动的算法,并将它和没有考虑浓度修正值影响的二阶矩湍流模型进行了对照。结果表明在二阶矩模型中是否考虑浓度修正影响会不同程度地影响流场的速度以及浓度等参数分布,考虑浓度修正影响的二阶矩湍流模型更能有效地预测稠密两相湍流流动。     

SOLITARY WAVES IN FINITE DEFORMATION ELASTIC CIRCULAR ROD

A new nonlinear wave equation of a finite deformation elastic circular rod simultaneously introducing transverse inertia and shearing strain was derived by means of Hamilton principle. The nonlinear equation includes two nonlinear terms caused by finite deformation and double geometric dispersion effects caused by transverse inertia and transverse shearing strain. Nonlinear wave equation and corresponding truncated nonlinear wave equation were solved by the hyperbolic secant function finite expansion method. The solitary wave solutions of these nonlinear equations were obtained. The necessary condition of these solutions existence was given also.     

双机头电脑刺绣机横梁的模态分析

以GY902A型电脑刺绣机的主横梁作为研究对象，分别运用实验测试和有限元模拟方法分析了电脑刺绣机横梁弯曲振动的固有频率，并利用经过验证的有限元模型，在计算机上作了结构改进仿真设计，实现了在不改变电脑刺绣机重量的前提下，电脑刺绣机横梁的固有频率提高22％，使电脑刺绣机更不易发生共振．     

磁悬浮控制力矩陀螺的高速转子模态分析及实验研究

采用通用有限元软件包ANSYS7．0，建立了控制力矩陀螺结构的有限元模型，对磁悬浮飞轮转子组件以及陀螺整体组合结构进行了模态分析。通过与实验结果对比，验证了模型的合理性和精确性，指出了盘轴相对弯曲模态是系统工作带宽内的主要模态，也是影响飞轮转子系统稳定性的主要原因之一，必须进行有效陷波处理。分析结果为电磁轴承控制器参数的选取以及陀螺框架的设计提供了依据；采用ANSYS参数设计语言APDL建立的有限元模型也为下一步的优化设计奠定了基础。     

Effects of static electric field on the fracture behavior of piezoelectric ceramics

The paper gives an overview on experimental observations of the failure behavior of electrically insulating and conducting cracks in piezoelectric ceramics. The experiments include the indentation fracture test, the bending test on smooth samples, and the fracture test on pre-notched (or pre-cracked) compact tension samples. For electrically insulating cracks, the experimental results show a complicated fracture behavior under electrical and mechanical loading. Fracture data are much scattered when a static electric field is applied. A statistically based fracture criterion is required. For electrically conducting cracks, the experimental results demonstrate that static electric fields can fracture poled and depoled lead zirconate titanate ceramics and that the concepts of fracture mechanics can be used to measure the electrical fracture toughness. Furthermore, the electrical fracture toughness is much higher than the mechanical fracture toughness. The highly electrical fracture toughness arises from the greater energy dissipation around the conductive crack tip under purely electric loading, which is impossible under mechanical loading in the brittle ceramics. The project supported by an RGC grant from the Research Grant Council of the Hong Kong Special Administrative Region, China     

Plane waves in a semi-infinite fluid saturated porous medium

The field equations governing the propagation of waves in an incompressible liquid-saturated porous medium are investigated and a general solution is presented. It has been revealed that coupled longitudinal and transverse waves propagate in the porous medium. The propagation of transverse waves in the fluid phase is completely due to the interaction between the solid and fluid phases. The dispersion relationship and attenuation features are discussed. Unlike other investigations, all explicit forms of the arguments are derived. The reflection of the plane harmonic waves at the plane, traction-free boundary, which shows the influence of the dissipation on the velocity, and the attenuation coefficients of the reflected waves is studied. It is of interest that pore pressure is produced in the process of reflection, even in the case of the incidence of transverse waves.     

环形板与扇形板弯曲问题的级数解

由板的基本方程,将位移和荷载沿环向展开为傅里叶级数,可得用傅里叶级数及多项式表示的环形板和直边简支的扇形板的级数解.还用富里叶级数处理沿径向分段连续荷载的问题.