双材料应力分析中的镜像点方法

提出一种分析各类双材料中任一点受集中力作用问题的方法.通过将结合界面或其自由表面看作镜面,将应力函数或位移函数设定成固定于受载点及其镜像点上的局部坐标系下的形式,利用界面连续条件和Dirichlet的单值性原理,所有应力函数或位移函数就可由无限体中集中力的解或半无限体表面集中力的解的应力函数求得.这种方法不仅可适用于单一界面的情况,也可使用于多个界面并存的情况,并且也可适用于具有自由表面的结合材料.这一方法可应用于各类结合材料、涂层薄膜材料、板材等.     

圆形刚性夹杂双周期分布的反平面问题

研究含双周期分布的圆形刚性夹杂在无穷远受纵向剪切的弹性平面问题，遵循复合材料中各夹杂相互影响的重要条件。采用复变函数方法。构造相应模型的复应力函数。通过坐标变换，同时满足夹杂边界位移条件，再利用围线积分将求争方程组化为线性代数方程组。导出了圆形刚性夹杂双周期分布的界面应力解析表达式。算例给出了界面应力最大值与夹杂间距的变化规律。求出了刚性夹杂的合理间距问题，本文发展的分析方法为研究夹杂材料的细观机理探索了一条有效的分析途径。     

多层材料结构的界面裂纹尖端复应力强度因子

本文建立了一种多层材料复合结构的界面裂纹问题分析模型。当两种材料之间插入第三种薄层弹性材料,裂纹位于第三种材料与第一或第二种弹性材料的界面上,且插页材料3~#的厚度相对于裂纹尺寸或平面内其他尺寸很小时,可以得到该问题裂纹尖端的复应力强度因子通式。本文用有限元法对结果进行了数值验证,并进行了有关问题的讨论。     

Near-Boundary Stress Wave Field in Anisotropic Plates under Impulsive Load

The stress wave field and the behavior of waves near the free boundary in an orthotropic plate and at the interface between two anisotropic media are studied. The results presented were obtained using the dynamic photoelastic method and optically sensitive fibrous models. Experimental data for impulsively loaded plates with various boundary conditions are analyzed     

剪切水-气界面下湍流猝发特征的实验研究

利用氢气泡时间线-脉线组合示踪技术定量地考察剪切水-气界面下的湍流猝发现象，分析 猝发事件的信号特征，重点探讨猝发与湍能产生之间的联系. 在猝发过程中，水面近区的瞬 时流速和Reynolds切应力出现较大幅度的脉动，它们在时间和空间垂直方向上表现出高度 的相干性，这是猝发事件的一个显著特征. 在猝发期，猝发事件涉及的空间区域内Reynolds 切应力和湍流脉动强度明显比平均值和非猝发期的情况大. 其结果表明：在所考察的实验 条件下，猝发是剪切水-气界面附近湍流产生的主要过程.     

On the Elastic Field of a Shpherical Inhomogeneity with an Imperfectly Bonded Interface

This study is devoted to the development of a unified and explicit elastic solution to the problem of a spherical inhomogeneity with an imperfectly bonded interface. Both tangential and normal displacement discontinuities at the interface are considered and a linear interfacial condition, which assumes that the tangential and the normal displacement jumps are proportional to the associated tractions, is adopted. The elastic disturbance due to the presence of an imperfectly bonded inhomogeneity is decomposed into two parts: the first is formulated in terms of an equivalent nonuniform eigenstrain distributed over a perfectly bonded spherical inclusion, while the second is formulated in terms of an imaginary Somigliana dislocation field which models the interfacial sliding and normal separation. The exact form of the equivalent nonuniform eigenstrain and the imaginary Somigliana dislocation are fully determined in this paper.     

界面动力学研究近况

界面动力学主要包括界面波动力界面动态断裂两人部分，本文评述了其主要研究课题的最新进展，并在此基础上展望了其发展趋势，指出界面模型研究、界面无损检测、界面动态损伤与破坏机理、界面动态断裂韧性及弹塑性面裂纹动态扩展等是当前最关心且急待解决的问题。     

Fluid Flows Through Two-Dimensional Channels of Composite Materials

The present analysis relates to the study of the full two-dimensional Brinkman equation representing the fluid flow through porous medium. The steady, incompressible fluid flow, with a negligible gravitational force, is constrained to flow in an infinitely long channel in which the height assumes a series of piecewise constant values. The control volume method is used to solve the Brinkman equation which involves the parameter, =/Da, where Da is the Darcy number and is the ratio of the fluid viscosity _f to the effective viscosity . An analytical study in the fully developed section of the composite channel is presented when the channel is of constant height and composed of several layers of porous media, each of uniform porosity. In the fully developed flow regime the analytical and numerical solutions are graphically indistinguishable. A geometrical configuration involving several discontinuities of channel height, and where the entry and exit sections are layered, is considered and the effect of different permeabilities is demonstrated. Further, numerical investigations are performed to evaluate the behaviour of fluid flow through regions which mathematically model some geological structures of various sizes, positions and permeability, for example a fault or a fracture, where the outlet channel is offset at different levels. The effect on the overall pressure gradient is also considered.     

树枝状界面相开裂对纤维强度的影响

碳纤维增强铝的复合材料在制造过程中，由于发生化学反应而在界面上形成新相。该相并非均匀附着在纤维表面，而是以纤维为主杆形成树枝状。本文利用剪切滞后理论，同时考虑到界面相亦有承受轴向外载的能力，分析了界面相开裂对纤维强度的影响。结果表明界面相与纤维间界面强度以及该界面脱粘后的摩擦应力的增加都能使纤维在给定外载下破坏的概率减小；另外界面相的厚度、沿纤维方向的弹性模量、剪切模量的增加却使上述概率增加。     

Dynamic load and inflation pressure effects on contact pressures of a forestry forwarder tire

A Trelleborg Twin 421 Mark II 600/55-26.5 steel-reinforced bias-ply forwarder drive tire at inflation pressures of 100 and 240 kPa and dynamic loads of 23.9 and 40 kN was used at 5% travel reduction on a firm clay soil. Effects of dynamic load and inflation pressure on soil–tire contact pressures were determined using six pressure transducers mounted on the tire tread. Three were mounted on the face of a lug and three at corresponding locations on the undertread. Contact angles increased with decreases in inflation pressure and increases in dynamic load. Contact pressures on a lug at the edge of the tire increased as dynamic load increased. Mean and peak pressures on the undertread generally were less than those on a lug. The peak pressures on a lug occurred forward of the axle in nearly all combinations of dynamic load, inflation pressure, and pressure sensor location, and peak pressures on the undertread occurred to the rear of the axle in most of the combinations. Ratios of the peak contact pressure to the inflation pressure ranged from 0 at the edge of the undertread for three combinations of dynamic load and inflation pressure to 8.39 for the pressure sensor on a lug, near the tire centerline, when the tire was underinflated. At constant dynamic load, net traction and tractive efficiency decreased as inflation pressure increased.