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81.
A method is proposed to solve the contact problem for laminated anisotropic shells of revolution. The method is based on a two-dimensional model that accounts for transverse shears and reduction. Also the method is based on the method of successive approximations, the generalized pseudo-force method, and a numerical-analytical method of solving boundary-value problems. The results obtained for a cylindrical shell of complex thickness structure are compared with those obtained in three-dimensional formulation__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 5, pp. 68–75, May 2005. 相似文献
82.
The Poincaré sphere representation of polarization states is used to derive two auxiliary equations for phase retardance measurements. These equations, in addition to another two previously derived equations, allow for extending the range of validity of a model for calibrating phase plates in pairs. In another application, the sphere is used to explain a new method for identifying the principal axes of two birefringent phase plates during their calibration. 相似文献
83.
Hairui Xia Jiyang Wang Lixia Li Zhigiang Zou 《Progress in Crystal Growth and Characterization of Materials》2000,40(1-4):253-261
A new series of non-ferroelectric crystals, the piezoelectric solid solution aluminium gallium orthophosphate Al1-xGaxPO4 (AGP, 0 < x < 1) system has been successfully developed by a hydrothermal method. The AGP crystal with X = 0.10 shows a phase transition temperature T−β = 587 ± 3 °C with a cell parameters A = b = 0.49386(3) and C = 1.09563(2) nm. Raman spectra including directional dispersion in AGP are similar to those from -AIPO4 and -quartz crystals, indicating all of them belong to an isomorphic family, the short-range interaction being dominant in AGP. Comparison with -AIPO4 crystals, there exists an apparent red shift of the mode frequency and a smaller TO/LO mode splitting of the E species in the AGP crystals. 相似文献
84.
The prediction of the high-cycle fatigue strength of polymeric and composite materials in asymmetric loading is considered.
The problem is solved on the basis of a nonlinear model of ultimate state allowing us to describe all typical forms of the
diagrams of ultimate stresses. The material constants of the model are determined from the results of fatigue tests in symmetric
reversed cycling, in a single fatigue test with the minimum stress equal to zero, and in a short-term strength test. The fatigue
strength characteristics of some polymers, glass-fiber laminates, glass-fiber-reinforced plastics, organic-fiber-reinforced
plastics, and wood laminates in asymmetric tension-compression, bending, and torsion have been calculated and approved experimentally.
__________
Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 1, pp. 87–102, January–February, 2008. 相似文献
85.
An in-depth investigation is made on the problem of an arc-shaped interface insulating crack in a three-phase concentric circular
cylindrical piezoelectric composite constitutive model. An exact solution in series form is derived by employing the complex
variable method. In addition, the distribution of physical quantities such as stresses, strains, electric displacements and
electric fields in the whole field and along the interface is also presented. Explicit expressions for crack opening displacement,
jump in electric potential on the crack surface and the electro-elastic field intensity factors at the crack tips are obtained.
Specific calculations demonstrate that the convergence of the series form solution is satisfactory and that the outer phase
(composite phase) will exert a significant effect on the electro-mechanical coupling response of the composite system. Owing
to the fact that stresses and electric displacements still possess conventional inverse square root singularities, the oscillating
singularities near the crack tip under plane strain conditions will be absent and, as a result, no unphysical interpenetration
phenomenon of the two crack surfaces will occur. In conclusion, the elastic solution obtained is also based on a solid physical
foundation.
Project supported by the National Natural Science Foundation of China (No.59635140), and the Doctorate Foundation of Xi'an
Jiaotong University. 相似文献
86.
Aliki D. Muradova 《Advances in Computational Mathematics》2008,29(2):179-206
In this paper a spectral method and a numerical continuation algorithm for solving eigenvalue problems for the rectangular
von Kármán plate with different boundary conditions (simply supported, partially or totally clamped) and physical parameters
are introduced. The solution of these problems has a postbuckling behaviour. The spectral method is based on a variational
principle (Galerkin’s approach) with a choice of global basis functions which are combinations of trigonometric functions.
Convergence results of this method are proved and the rate of convergence is estimated. The discretized nonlinear model is
treated by Newton’s iterative scheme and numerical continuation. Branches of eigenfunctions found by the algorithm are traced.
Numerical results of solving the problems for polygonal and ferroconcrete plates are presented.
Communicated by A. Zhou. 相似文献
87.
Saqlain Abbas Fucai Li Zulkarnain Abbas Taufeeq Ur Rehman Abbasi Xiaotong Tu Riffat Asim Pasha 《声与振动》2021,55(1):1-18
Structural health monitoring (SHM) is recognized as an efficient tool to interpret the reliability of a wide variety of infrastructures. To identify the structural abnormality by utilizing the electromechanical coupling property of piezoelectric transducers, the electromechanical impedance (EMI) approach is preferred. However, in real-time SHM applications, the monitored structure is exposed to several varying environmental and operating conditions (EOCs). The previous study has recognized the temperature variations as one of the serious EOCs that affect the optimal performance of the damage inspection process. In this framework, an experimental setup is developed in current research to identify the presence of fatigue crack in stainless steel (304) beam using EMI approach and estimate the effect of temperature variations on the electrical impedance of the piezoelectric sensors. A regular series of experiments are executed in a controlled temperature environment (25°C–160°C) using 202 V1 Constant Temperature Drying Oven Chamber (Q/TBXR20-2005). It has been observed that the dielectric constant ε33T which is recognized as the temperature-dependent constant of PZT sensor has sufficiently influenced the electrical impedance signature. Moreover, the effective frequency shift (EFS) approach is optimized in term of significant temperature compensation for the current impedance signature of PZT sensor relative to the reference signature at the extended frequency bandwidth of the developed measurement system with better outcomes as compared to the previous literature work. Hence, the current study also deals efficiently with the critical issue of the width of the frequency band for temperature compensation based on the frequency shift in SHM. The results of the experimental study demonstrate that the proposed methodology is qualified for the damage inspection in real-time monitoring applications under the temperature variations. It is capable to exclude one of the major reasons of false fault diagnosis by compensating the consequence of elevated temperature at extended frequency bandwidth in SHM. 相似文献
88.
89.
从虚功原理出发,证明了薄板小挠度弯曲问题的功的互等定理,并由此推出了求解矩形薄板自然频率的公式.算例表明,该公式计算简便,精度较高. 相似文献
90.