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41.
An annular interfacial crack between dissimilar piezoelectric layers subjected to electroelastic loadings was investigated under an electrically impermeable boundary condition on the crack surface by using the Hankel transform technique and the Cauchy singular integral equation method. The stress intensity factors and energy release rates were determined. Numerical results reveal the effects of crack configuration, electric loads and material parameters on crack propagation and growth. The results should be useful for the design of piezoelectric composite structures and devices of high performance. 相似文献
42.
An analytical solution based on a new exact closed form procedure is presented for free vibration analysis of stepped circular and annular FG plates via first order shear deformation plate theory of Mindlin. The material properties change continuously through the thickness of the plate, which can vary according to a power-law distribution of the volume fraction of the constituents, whereas Poisson’s ratio is set to be constant. Based on the domain decomposition technique, five highly coupled governing partial differential equations of motion for freely vibrating FG plates were exactly solved by introducing the new potential functions as well as using the method of separation of variables. Several comparison studies were presented by those reported in the literature and the FEM analysis, for various thickness values and combinations of stepped thickness variations of circular/annular FG plates to demonstrate highly stability and accuracy of present exact procedure. The effect of the geometrical and material plate parameters such as step thickness ratios, step locations and the power law index on the natural frequencies of FG plates is investigated. 相似文献
43.
44.
Bouchra Belhaj Abdallah Ahmed Landoulsi Abdelwaheb Chatti 《Journal of Saudi Chemical Society》2018,22(1):110-118
The instant biosynthesis of silver nanoparticles under static electromagnetic induction, its antibacterial activity and its post exposure monitoring were reported here. A mix of silver nitrate solution and Ruta chalepensis leaf extract was irradiated by a static electromagnetic field (SMF) of 200 mT. The characteristics and stability of the biosynthesized silver nanoparticles (Ag NPs) were determined. Compared to the non-irradiated exposure, the morphology and state of the obtained material change once the exposition to SMF is turned off. Shifting from 453 to 473 nm, the percentage of the needles shaped silver nanoparticles increased and continue to win and dominate the biomixture toward the spherical silver nanoparticles. TEM microscopy showed a wide range of silver materials designed in different nanoscale morphology and beyond where they undergo major changes affecting mainly the size, shape and form (dispersity) of nanosilver. 相似文献
45.
On the basis of Von Kármán equations,the thermal-buckling of thin annular platessubjected to a field of non-uniform axisymmetric temperature and a variety of boundaryconditions is discussed.The linearized problem is analyzed and stability boundaries whichcharacterize instability of a plate are obtained by means of numerical and analysis methods. 相似文献
46.
石油钻井和完井过程中,经常出现泥浆、水泥浆和完井液在偏心环空中的流动。Robertson-Stif流体在描述这些流体的流变性时有很高的精度。文中根据Robertson-Stif流体的流变方程和偏心环空环隙间距的几何关系,利用相似原理,求解了该流体在偏心环形空间中作层流轴向流动时适于工程应用的二元速度分布,以及平均流速、流量和压降的表达式。研究表明:液体在偏心环形空间流动时与在同心环空中流动的最大差异,在于流经偏心环空不同间隙处流速的较大差异。文中还把Robertson-Stif流体的计算结果与采用宾汉模式和幂律模式的计算结果进行了对比。 相似文献
47.
本文研究幂律非牛顿流体在环管内的不定常旋转流。该方程是一非线性方程,在部分因子的稳态近似假设之下,方程被线性化,用Laplace积分变换法我们获得了问题的解。文中给出了几组解曲线,它反映了角向速度的时间演化规律与空间分布特征。另外我们专门研究了幂律指数对流场的影响,该参数的敏感性具有一定的数值界限。这一结果,在有关的工程设计中具有重要的意义。 相似文献
48.
付宝连 《应用数学和力学(英文版)》1985,6(9):879-885
In this paper in the terms of theory we have proved that the reciprocal theorem isequivalent to the superposition principle of displacements and is equivalent to thesuperposition principle of reactive forces. These equivalents have important theoreticalvalues and practical values.At the same time we also point out that Castigliano’s displacement equation can beapplied to solve the interior displacement of the region of the deformable body too. 相似文献
49.
WANG Youqing HUANG Xintang CHEN Q. M. QIU J. L. XU Q. Y. 《Chinese Journal of Lasers》1999,8(2):109-115
1IntroductionSincethefirstrealizationoftheoperationofawaveguidegaslaserbySmith[1]in1971,considerablestudieshavebeenmadeonthew... 相似文献
50.
An approach of calculating the coupling losses in a coaxial (or annular) waveguide laser resonator is developed by which the computational time is considerably reduced. Computations of the coupling losses for some TE modes of an annular waveguide, as a function of mirror curvature and position, are presented in the limit of large mirror aperture. It is shown that there exist three special configurations to provide low coupling losses. The resonator properties are discussed. The calculating results are useful for design of annular waveguide laser resonators. 相似文献