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61.
62.
K0.9Li0.1(Ta0.5Nb0.5)O3晶体压电应变系数的测量 总被引:4,自引:2,他引:2
用准静态d_(33)测量仪和干涉法相结合。测量了K_(0.9)Li_(0.1)(Ta_(0.5)Nb_(0.5)Nb_(0.5))O_3晶体的压电应变系数。结果为:d_(33)=86.0,d_(33)=一29.5,d_(15)=112.9×10 ̄(-12)C/N. 相似文献
63.
本文对离散Kirchhoff薄板单元进行了深入的分析。文中将用于建立离散Kirchhoff单元的泛函分为三部分,分别用应变第一不变量、绕Z轴的转动偶和有关的单元边界上的积分来表达,并阐明了各部分的作用。其中单元的收敛性质完全由第一、三部分所决定,而第二部分则控制了单元的计算精度。在此基础上,文中建议了一种提高离散Kirchhoff单元精度的新方法,并由此推导了一个任意四边形离散Kirchhoff单元。计算表明,本文的改进单元与原来的离散Kirchhoff单元及其改进型相比,计算精度有了显著提高。 相似文献
64.
Analytical solution for the axisymmetric plane strain electroelastic dynamics of a special non-homogeneous piezoelectric hollow cylinder 总被引:1,自引:0,他引:1
By virtue of the introduction of a dependent variable and the separation of variables technique, the axisymmetric plane strain electroelastic dynamic problem of a special non-homogeneous piezoelectric hollow cylinder is transformed to a Volterra integral equation of the second kind about a function with respect to time, which can be solved successfully by means of the interpolation method. Then the solutions of displacements, stresses, electric displacements and electric potential are obtained. The present method is suitable for a piezoelectric hollow cylinder with an arbitrary thickness subjected to arbitrary mechanical and electrical loads. Numerical results are finally presented. 相似文献
65.
M. Nishida T. Hanabusa Y. Ikeuchi N. Minakawa 《Materialwissenschaft und Werkstofftechnik》2003,34(1):49-55
Stress measurement methods using neutron and X‐ray diffraction were examined by comparing the surface stresses with internal stresses in the continuous tungsten‐fiber reinforced copper‐matrix composite. Surface stresses were measured by X‐ray stress measurement with the sin2ψ method. Furthermore, the sin2ψ method and the most common triaxal measurement method using Hooke's equation were employed for internal stress measurement by neutron diffraction. On the other hand, microstress distributions developed by the difference in the thermal expansion coefficients between these two phases were calculated by FEM. The weighted average strains and stresses were compared with the experimental results. The FEM results agreed with the experimental results qualitatively and confirmed the importance of the triaxial stress analysis in the neutron stress measurement. 相似文献
66.
The failure of acetabular cups via loosening, migration or fracture is partially related to the stress distribution existing in the acetabular region. The complexity of the investigation of these stresses demands the application of a variety of model testing techniques involving combined embedded strain gauging, finite element analysis, transmission and reflective photoelasticity and crack propagation studies. The application of these procedures are described and the difficulties of obtaining representative loadings and restraints are commented upon. 相似文献
67.
The isothermal strain‐life approach is the most commonly used approach for determining fatigue damage, particularly when yielding occurs. Computationally it is extremely fast and generally requires elastic finite element analyses only. Therefore, it has been adapted for variable temperatures. Local temperature—stress–strain behaviour is modelled with an operator of the Prandtl type. The hysteresis loops are supposed to be stabilized and no creep is considered. The consequences of reversal point filtering are analysed. The approach is finally compared to several thermo‐mechanical fatigue tests and the Skelton model. 相似文献
68.
The paper reports the experimental investigation data for the effect that nonparallel faces of bars under impact exert on
the parameters of longitudinal and bending strain waves generated in the bars. The changes in stress magnitudes in the bar
under impact with growing angle of the impact faces offset are described.
__________
Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 73–78, November–December, 2006. 相似文献
69.
The spatiotemporal aspects of the Portevin–Le Chatelier effect in Al–Mg alloys are investigated using direct observations of the sample surface with a digital camera. Optical measurements of the surface profile using a white light interferometer allow the estimation of the local strain and strain rate associated with the bands. The effect of Mg content on instability characteristics is analyzed. The reloading time is shown to depend on the Mg content only at the strain and strain rates where type C bands are observed. 相似文献
70.