考虑材料拉压强度异性的简支圆板塑性极限统一解

采用统一强度理论首次对简支圆板在边缘均布荷载作用下的塑性极限进行了求解，得出了相应的统一解形式以及统一强度理论参数b和拉压强度比α对塑性极限的影响曲线。所给出的解可以适用于各种不同特性的材料。利用本文的解还可以得到一系列新的结果，可以更好的发挥材料的强度潜能，取得明显的经济效益。     

一个弹-粘塑性问题的统一解析解

采用统一强度理论对平面应变轴对称问题在弹－粘塑性状态下的解析解进行了分析,由此得到的统一解可以蜕化成一系列从Ｍｏｈｒ－Ｃｏｕｌｏｍｂ单剪强度理论到双剪强度理论的平面应变轴对称问题解析式。献中已有的关于弹－粘塑性问题的单剪解为本的特例,统一强度理论可以给出更符合各种不同材料特性的合理解。     

刚度微分法计算压电材料平面断裂问题

把计算应变能释放率的刚度微分法推广到压电材料平面断裂问题．在此基础上，利用压电材料平面断裂问题的有限元数值解作为真实场，用Ｓｏｓａ的平面问题裂端渐近解作为辅助场，由推广的交互Ｍ积分法求得了应力强度因子ＫＩ，ＫＩＩ和电位移强度因子ＫＩＶ．算例表明，计算结果与理论解符合得很好     

考虑材料拉压异性的固支圆板塑性极统一解

本文采用最新的统一强度理论求出了固支圆板的塑性极限荷载,内力场及速度的统一解;得出了强度理论参数b及材料的不同拉压比α对塑性极限的影响曲线,所给出的解可以灵活地适用于各种不同特性的材料及机械、土木、航空等工程的相关结构中,文献中已有的Tresca解,Mises解和双剪统一屈服准则解均为本文的特例,本文的统一解还给出了一系列新的结果,统一解大于Tresca,Mohr-Coulomb的单剪理论解,它可以更好地发挥材料的强度潜力,工程应用可以取得明显的经济效益。     

用统一平面应就滑移线场理论求解厚壁圆筒的极限荷载

用统一平面应变滑移线场理论，得到了拉压性能不同材料的厚壁圆筒的极限荷载统一解，它也可以适用于拉压强度相等的材料，能充分发挥材料性能，减轻结构重量，取得多方面的经济效益。     

线性荷载作用下外简支环板的极限荷载分析

对于线性荷载作用下外简支环板,引入统一强度理论,进行了极限荷载分析。并分别求出了两种特殊形式的线性荷载作用下的极限荷载统一解,得出参数b值及材料的拉压比α对极限荷载的影响曲线。统一强度理论中,选择不同的参数b,可以得到一系列不同的屈服准则,不同的b值可以对应不同的工程材料,其中b=0和b=1分别给出了下限解和上限解。工程实际中,α可根据实际材料的拉压强度直接确定。当α=1时,统一强度理论适用于拉压强度相同的材料,当a≠1时,适用于拉压强度不同的材料。因此文中所给出的解可以灵活应用于各种性能的材料,可以充分反映材料的SD效应及中间主应力效应。已有的Tresca准则,Mises准则,双剪应力屈服准则以及双剪统一屈服准则的解答均为本文解答的特例或线性逼近。     

简支圆板在复杂荷载作用下的塑性极限荷载统一解析解

本文采用双剪统一屈服准则对受线性荷载和边缘弯矩联合作用下的简支圆板进行了塑性极限分析，考虑了联合作用的两种形式，分别给出了统一的解析解。得到了极限荷载随不同屈服准则的变化曲线。对于不同的材料，本文均能给出相应的极限荷载。已有的Tresca准则、Von Mises准则、双剪应力准则的解答是文中解答的特例或逼近。本文得到的一系列有规则变化的解析解，可以适用于各种拉压强度相同材料的简支圆板的塑性极限荷载求解。文中统一解大于Tresca单剪理论解，它可以更好地发挥材料的强度潜力，工程应用可以取得明显的经济效益。     

用统一平面应变滑移线场理论求解厚壁圆筒的极限荷载

用统一平面应变滑移线场理论,得到了拉压性能不同材料的厚壁圆筒的极限荷载统一解,它也可以适用于拉压强度相等的材料,能充分发挥材料性能,减轻结构重量,取得多方面的经济效益。     

冲击荷载作用下简支圆板的塑性动力响应统一解

采用统一强度理论求解了简支圆板在中等脉冲荷载作用下的动力响应问题,得出了统一的动力塑性极限荷载、内力场和速度场,并给出了上限解和下限解。讨论了静力许可条件和运动许可条件。利用本文的解还得出了简支圆板在静力荷载作用下的极限荷载、内力场和速度场。根据选择不同的拉压比参数,本文所给出的解可以适用于各种拉压异性和拉压同性材料。Tresca解、Mohr Coulomb解和双剪统一屈服准则解是本文的特例,Mises解是本文当=1和b=0.5时的线性逼近。研究结果表明,拉压比和强度理论参数b对动力解的影响要大于对静力解的影响,所以,根据材料的不同选择合适的强度理论,对于更好的发挥材料的强度潜力,减轻结构的重量具有重要的意义。     

线性强化材料厚壁圆筒的统一极限分析

运用统一强度理论对承受内压的拉压屈服强度不同的线性强化材料的厚壁圆筒进行了极限载荷分析，得到了适用于多种材料的厚壁圆筒极限载荷的统一解析式．     

Force Action of a Body with a Permeable Boundary on a Wall in a Fluid

The ideal fluid flow due to fluid penetration through the boundary of an infinitely long solid cylinder in contact with a solid wall is determined. A formula is derived according to which the force exerted by a finite-length part of the cylinder on the wall is directed into the wall and can thus have an arbitrarily large absolute value. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 1, pp. 82–84, January–February, 2006.     

On a Paradox in the Motion of a Rigid Particle along a Wall in a Fluid

The results of an experimental investigation of spherical particles with different surface roughnesses rolling under their own weight down an inclined pipe wall in a Newtonian fluid at low Reynolds numbers, both with (friction should be taken into account) and without contact with the wall, are presented. It is shown that a fixed particle moves differently in different fluids with similar viscosities and densities. This fact, as well as the possibility of particle motion without contact with the wall, cannot be explained within the framework of the usual hydrodynamic theories. An example is the dependence of the particle motion on the static pressure.     

Torsion problems for a cylinder with a rectangular hole and a rectangular cylinder with a crack

Using the method of singular integral equation and the crack-cutting technique, the rigorous solutions are obtained for a cylinder with a rectangular hole and a rectangular cylinder with a crack, which exactly satisfy the boundary conditions and the conditions at the corner points. After that the torsional rigidities and the stress intensity factors at the crack tip are determined. Next, for the doubly connected circular cylinder with a rectangular hole the expressions for the singular stresses around the concave corner points are derived and the generalized stress intensity factors are then defined. Since the crack-cutting technique is used in this paper, the solution of the matching rectangular cylinder is also obtained and its numerical results coincide with those in references. Thus the method proposed here is verified. The project supported by National Natural Science Foundation of China     

Pumping of a fluid through a microchannel by means of a bubble driven by a light beam

A new method of pumping a fluid through a microchannel device using a gas bubble-piston, set in motion by the thermocapillary force induced by a light beam, is proposed. To demonstrate the method, a model micropump has been assembled. The model consists of two reservoirs connected by two channels with a bubble-piston driven by a light beam. The pumping rate and the volume per piston stroke are evaluated experimentally. The method proposed is compared with known microfluid pumping methods. Some advantages of the new method are indicated.     

Interaction of a screw dislocation with a notch in a piezoelectric bi-material

Summary The electro-elastic interaction of a screw dislocation and a notch in a piezoelectric bi-material is analyzed. The electro-elastic fields induced by the dislocation are derived using the conformal mapping and the image-dislocation approach, where the solution for a piezoelectric bi-material without a notch is used as a base. The stress and the electric displacement intensity factors of the notch and the image force on the dislocation are given explicitly. We find that intensity factors are expressed in terms of the effective material constants, while the radial component of the image force is independent of the notch angle and the angular position of the dislocation in the polar coordinate system. Numerical results for the image force are provided for the use when one of the two media is purely elastic. They illustrate the behavior of the dislocation in the neighborhood of the notch.     

Diffusive shrinkage of a void within a grian of a stressed polycrystal

A method to predict the shrinkage rate of a void centered at an equiaxial grain under hydrostatic pressure is developed. The rate process is controlled by lattice diffusion under the combined influence of void surface energy, grain boundary interface energy and elastic energy stored in the solid. A dimensionless loading parameter that controls the void evolving is introduced. Below a certain value of this parameter the void will be rounded and is stable. Then the shrinkage behavior of the voids is described by the parameters controlling the lattice diffusion. It is found that only gas-free voids could be totally eliminated through lattice diffusion; for a gas-filled void, the internal pressure produced by the gas firstly retards the rate of the shrinkage and eventually stops the shrinkage process as it becomes high enough.     

Transformation of a breaking wave at a drop of a channel bottom

This paper gives results of an experimental study of incident and reflected waves of the bore type in the neighborhood of a sharp change in the channel bed level. It is shown that under conditions typical of accidents at ship locks, the wave height can reach 8 m.Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 2, pp. 115–121, March–April, 2005.     

Growth of a new phase in a substance in a metastable state

A model of kinetics of phase transitions in a substance in a metastable state is proposed, where the probability of extensive nucleation owing to homogeneous mechanisms is rather large; the model is an alternative to Kolmogorov’s model. The use of this model is demonstrated to offer analytical solutions that describe both the crystallization processes with similar densities of the liquid and solid phases and, for instance, the kinetics of nucleation and growth of bubbles in surface boiling. Solutions obtained by Kolmogorov’s model and by the present model coincide at the initial stage of the process where the volume fraction of the new phase is small. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 2, pp. 75–80, March–April, 2007.     

Dynamics of a vapor shell around a heated particle in a liquid

The dynamics and heat and mass exchange of a vapor bubble containing a heated particle is studied in relation to the problem of vapor explosions. It is shown that the process involves two stages: dynamic stage and thermal stage. The dynamic stage is characterized by pressure fluctuations and a rapid increase in the thickness of the vapor layer. It is shown that the simplifying assumptions of the constancy of assumptions of constant heat conductivity of the vapor and linear temperature profile in the vapor layer lead to qualitatively incorrect results. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 4, pp. 69–78, July–August, 2007