Herz接触问题的解的唯一性条件

讨论了接触面为圆面的Ｈｅｒｔｚ接触问题。若压会布是轴对称的，则该接触问题的解必是唯一的。且在上述条件下，该接触问题的积分方程化为两个推广的Ａｂｅｌ积分方程组，此方程组的解便给出此接触问题的解。     

夹层板的边界单元法

本文提出了Ｒｅｉｓｓｎｅｒ型和Ｈｏｆｆ型夹层板的直接边界单元法。从夹层弯曲问题的基本方程出发，利用偏微分算子导出夹层板偏微分方程的基本解，收此建立起问题的边界积分方程组，采用边界元法求解，所得结果具有较高精度。     

论Hertz接触问题解的不唯一性

本文根据积分方程的理论,对Hertz接触问题的积分方程的特点进行了分析,指出该问题的解不是唯一的。     

三维断裂力学的超奇异积分方程方法

本文利用有限部积分的概念和方法,严格地证明了三维弹性体中受任意载荷作用的平片裂纹问题的超奇异积分方程组,并对未知解的性态作了理论分析,得到了性态指数,在此基础上通过主部分析,精确地求得了裂纹前沿光滑点附近的奇性应力场,从而找到了以裂纹面位移间断(位错)表示的应力强度因子表达式,最后对所得的超奇异积分方程组建立了数值法,并用此计算了若干典型的平片裂纹问题,数值结果令人满意。     

复合型运动荷载作用下横观各向同性体三维裂纹的应力强度因子

讨论横观各向同性体中含一半平面裂纹,在裂纹面上作用有运动点荷载的三维复合型应力强度因子历史,通过积分变换技术,最终将问题归结为求解Wiener-Hopf型积分方程组,该文给出了求解这一类积分方程组的一般性方法,在此基础上,基于Abel定理和Cagniard-deHoop方法,求得Ⅱ、Ⅲ型复合应力强度因子的解析解,最后通过数值结果揭示了横观各向同性材料三维方尖端场的动态特性。     

层状弹性半空间非轴对称动力问题的奇异解

在柱坐标系下，利用关于方位角的Ｆｏｕｒｉｅｒ变换及关于径向的Ｈａｎｋｅｌ变换，将弹性力学基本方程组转化为非齐次的一阶常微分方程组的标准形式．采用求解微分方程组的矩阵法，建立了介质层的传递矩阵．由层间完全接触条件，导出了在任意埋藏源作用下层状弹性半空间频域奇异解，时域奇异解可通过关于频率的Ｆｏｕｒｉｅｒ积分得到．该方法可应用到固体、流体层的情况     

尖端具有吸附性接触的界面裂纹对瞬态弹性波作用下的动态响应

建立并研究一类接触型界面裂纹模型对瞬态弹性波作用下的动态响应问题。文中利用积分变换和积分方程法推导了确定这类问题的奇异积分方程组。采用围道积分技术和切比雪夫多项式展开技术，得到了待定系数的非线性代数方程组。最后给出了裂纹尖端接触区大小和接触应力随时间变化的数值结果，揭示了这种接触裂纹的动力学特性及物理上的合理性。     

表面堆载作用下群桩负摩擦研究

利用Biot固结理论和积分方程方法研究了表面有堆载的群桩负摩擦问题。根据基本解得出了群桩在圆形均布载荷作用下在时间域内的第二类Fredholm积分方程组。运用Laplace变换对上述积分方程组进行简化，求解上述积分方程组并进行相应的数值逆变换就可得出群桩在表面圆形均布载荷作用下的变形、轴力、孔压和桩侧摩阻力随时间的变化情况。     

带裂纹组合柱的扭转

本文联合使用组合柱体扭转的单层势函数解及均质柱体扭转的单裂纹解,对带有裂纹的组合柱体的扭转作了讨论,最后将问题归结为解一组混合型积分方程,并为其建立了数值方法,对于裂纹与材料分界面接触的情形,本文通过积分方程组的主部分析,精确地求得了奇性指数的特征方程。文中对组合柱的抗扭刚度和裂纱端点的应力强度因子作了数值计算,与文献上已有的结果符合很好。     

弹性体表面分层压缩失稳问题的数学弹性力学解

采用数学弹性力学的稳定平衡方程并结合富氏积分变换的方法研究了含表面平行裂纹的弹性体在压缩载荷下的表面分层失稳问题。导出了一级显式的精确齐次奇异积分方程组,然后.通过Gauss-Chebyshev积分公式,得到一组齐次代数方程组,从而求出临界压缩载荷。并将结果与经典的材料力学梁板稳定的研究方法所得结果进行了比较,指出经典方法误差太大而不适于求解此问题。最后,利用数学弹性力学解求出的等效弹性支承常数给出一个简单精确的临界压缩载荷计算公式。     

THE EXACT INTEGRAL EQUATION OF HERTZ’S CONTACT PROBLEM

This paper presents the exact integral equation of Hertz‘s contact problem,which isobtained by taking into account the horizontal displacement of points in the contactedsurfaces due to pressure.     

The axisymmetric partial slip contact problem of a graded coating

In this paper, the axisymmetric contact problem with the partial slip condition for a functionally graded coated half-space which is indented by a rigid spherical indenter is considered. The material properties are assumed to vary along the thickness of the coating. A series of linear functions of the thickness are used to model the functionally graded coating with the arbitrarily varying shear modulus. The contact problem is formulated in terms of a set of Cauchy singular integral equations by employment of Hankel integral transforms technique and transfer matrix method. By using the uncoupled solution and the coupled solution,the coupled equations are solved. The effect of the coating’s gradient on the normal and radial tractions in the whole contact region is presented. The results show that the contact tractions and the size of the stick zone can be altered by adjusting the gradient of the coating. This may have potential applications in the resistance of contact deformation and damage.     

Analytical solution of the contact problem for a system of bodies under collective wear

The contact problem is considered for a system of bodies subject to wear on a common base. The deformation properties of the bodies and the base are described by the Winkler model. The problem is reduced to a system of ordinary differential equations and an integral equation of hereditary type with difference kernel. The solution of the problem is constructed with the use of the Laplace transform. The asymptotics of the solution at large times is studied. The continuity conditions for the contact of each of the bodies with the base are derived.     

Mechanics of indentation for piezoelectric thin films on elastic substrate

Frictionless normal indentation problem of rigid flat-ended cylindrical, conical and spherical indenters on piezoelectric film, which is either in frictionless contact with or perfectly bonded to an elastic half-space (substrate), is investigated. Both conducting and insulating indenters are considered. With Hankel transform, the general solutions of the homogeneous governing equations for the piezoelectric layer and the elastic half-space are presented. Using the boundary conditions for a vertical point force or a point electric charge, and the boundary conditions on the film/substrate interface, the Green’s functions can be obtained by solving sets of simultaneous linear algebraic equations. The solution of the indentation problem is obtained by integrating these Green’s functions over the contact area with unknown surface tractions or electric charge distribution, which will be determined from the boundary conditions on the contact surface between the indenter and the film. The solution is expressed in terms of dual integral equations that are converted to a Fredholm integral equation of the second kind and solved numerically. Numerical examples are also presented. The comparison between two film/substrate bonding conditions is made. It shows that the indentation rigidity of the film/substrate system is lower when the film is in frictionless contact with the substrate. The effects of the Young’s modulus and Poisson’s ratio of the elastic substrate, indenter electrical condition and indenter prescribed electric potential on the indentation responses are presented.     

On Indentation of a System of Irregularly Shaped Rigid Punches into a Coated Foundation

We consider the contact problem of interaction between a coated viscoelastic foundation and a system of rigid punches in the case where the punch shape is described by rapidly varying functions. A system of integral equations is derived, and possible versions of the statement of the problem are given. The analytic solution of the problem is constructed for one of the versions.     

Contact interaction of a rigid heat-conducting punch with an elastic layer involving nonstationary frictional heating

A mathematical formulation is given and a solution is found to the quasistatic contact problem of thermoelasticity for a rigid heat-conducting punch moving over an elastic layer with fixed base. The interaction is accompanied by heating due to frictional forces obeying Amonton’s law. The problem is reduced to a system of integral equations with time-varying limits of integration. The structure of these equations depends on the type of thermal and physical conditions on the contact surface. An algorithm is proposed for the numerical solution of this kind of equations. The variation in the contact pressure and contact area with time is studied __________ Translated from Prikladnaya Mekhanika, Vol. 41, No. 12, pp. 35–46, December 2005.     

Frictional contact problem for a rigid cylindrical stamp and an elastic layer resting on a half plane

The frictional contact problem for a layer resting on a homogeneous half plane is handled using linear elasticity theory in this study. The layer is in contact with a rigid cylindrical stamp that is on the layer and applies a concentrated force in the normal and tangential directions. Friction between the component couples of layer–stamp and layer–half plane is taken into account. The problem is reduced to a system of singular integral equations, in which the contact pressures and the contact areas are the unknowns, and it is treated using Fourier transforms and the boundary conditions for the problem. The system of singular integral equations is solved numerically using the Gauss–Jacobi integration formula with equilibrium and consistency conditions. Numerical results for the contact pressures and the contact areas are given as a solution for both the frictional and the frictionless cases. This work is the first study that investigates the effect of friction on the receding contact problem of a layer and a half plane with two contact areas.     

NUMERICAL SIMULATION OF TWO-POINT CONTACT BETWEEN WHEEL AND RAIL

The elastic-plastic contact problem with rolling friction of wheel-rail is solved using the FE parametric quadratic programming method. Thus, the complex elastic-plastic contact problem can be calculated with high accuracy and efficiency, while the Hertz＇s hypothesis and the elastic semi-space assumption are avoided. Based on the ‘one-point＇ contact calculation of wheel-rail, the computational model of ‘two-point＇ contact are established and calculated when the wheel flange is close to the rail. In the case of ‘two-point＇ contact, the changing laws of wheelrail contact are introduced and contact forces in various load cases are carefully analyzed. The main reason of wheel flange wear and rail side wear is found. Lubrication computational model of the wheel flange is constructed. Comparing with the result without lubrication, the contact force between wheel flange and rail decreases, which is beneficial for reducing the wear of wheel-rail.     

十二次对称二维准晶中的无摩擦接触问题

利用积分变换的方法讨论了在一个刚性压头作用下十二次对称二维准晶的无摩擦接触问题. 通过引入位移势函数,将数量巨大而复杂的偏微分方程转化为两个独立的双调和方程,应用Fourier分析与对偶积分方程理论解决了十二次对称二维准晶材料的无摩擦接触问题,得到了相应的接触应力解析表达式,结果表明：如果接触位移是一常数,则接触应力在接触区域边缘具有-1/2阶奇异性;反之,如果接触应力在接触区域边缘具有-1/2阶的奇异性,则接触位移一定为一常数,这为准晶材料的接触变形提供了重要的力学参数.