Papers by Keyword: Anisotropic

Abstract: A failure criterion is proposed for complex rocks and soils. Their anisotropic and nonlinear behavior is analyzed theoretically and experimentally. The influence of the intermediate principal stress is taken into account. The nonhomogeneous strength and the effect of geological temperature are also discussed. Many classical failure criteria are special cases of the proposed condition. The criterion is applied in the analysis of the bedrock of Ankang Dam in China. The case study illustrates the potential of the proposed general model in engineering application.

Abstract: 33 records of Japanese earthquake are extracted in this paper (referred to as 3.11 seismic waves in the article).Then, through studying the basic characteristics, spectrum characteristics and anisotropic of 3.11 seismic waves, as well as the similarities and differences of the response spectrum of 3.11 seismic waves contrasting with the response spectrum of the code. The results show that: a) 3.11 seismic waves have rich spectral components almost near the predominant frequency and its energy mainly concentrate in 0.1~10Hz.b) By analyzing the spectrum distribution of the seismic waves, its destruction strength on different structures can be evaluated. c) Damaging strength of horizontal seismic waves is much larger than the vertical seismic waves. Serious damage to the structure can be caused by the horizontal seismic waves’ excellence spectrum components focusing on the frequency of the structure in the engineering. Vertical seismic waves have greater damage to the structures’ periods between 0.02s to 1s, but much smaller to other structures. d) it can effectively assess the damaging strength on the structure,in time history analysis ,when make 3.11 seismic waves as the input earthquake waves.

Abstract: Photothermal displacement technology is mainly applied in the measurement of the materials optical thermal parameters and the non-destructive testing. In order to study the optical thermal parameters of the anisotropic crystal, heat conduction equation of anisotropic crystal under a given temperature distribution is solved by using an integral transform method. The steady-state temperature field distribution of the crystal is obtained, which is simulated by Matlab and can be applied to the photothermal displacement technology to obtain the surface deformation to provides a strong theoretical basis for studying the optical thermal parameters of the sample.

Abstract: Negative refraction is a fantastic optical property and attracts more and more attentions. As first proposed, materials with negative permittivity and negative permeability simultaneously exhibit negative refraction. Recently, negative refraction was found in the indefinite medium based on the strong anisotropy of permittivity. In this paper, the theory of the negative refraction in the anisotropic materials and the research progress in recent years were reviewed.

Abstract: Related with the detection of weak magnetic fields, the anisotropic magnetoresistive (AMR) effect is widely utilized in sensor applications. Exchange coupling between an antiferromagnet (AF) and the ferromagnet (FM) has been known as a significant parameter in the field sensitivity of magnetoresistance because of pinning effects on magnetic domain in FM layer by the bias field in AF. In this work we have studied the thermal evolution of the magnetization reversal processes in nanocrystalline exchange biased Ni₈₀Fe₂₀/Ni-O bilayers with large training effects and we report the anisotropic magnetoresistance ratio arising from field orientation in the bilayer.

Abstract: The two-dimensional problem of an elliptic inclusion embedded into an anisotropic magneto-electro-elastic solid is studied. Based on the Stroh formalism combined with the technique of conformal mapping and the method of analytical continuation, general solutions for the stress and deformations in the entire domain are obtained when a generalized line force and a generalized line dislocation is located at a point outside, inside, or on the interface of an elliptical inclusion. Comparisons with some related solutions show that the present solutions are valid and general.

Abstract: Flow behavior of gas and particles is predicted by the large eddy simulation of gas-second order moment of solid model (LES-SOM model) in the simulation of flow behavior in CFB. This study shows that the simulated solid volume fractions and velocity along height using a two-dimensional model are in agreement with experiments. The second-order moments of particles are computed.

Abstract: The crack behavior of Si-doped GaAs crystals produced by a novel pulling-down method was investigated. Some cracks were observed in the crystal tail part and no twins or polycrystals were observed. The cracking mechanism was discussed considering the growth parameters, such as the pulling-down rate, annealing time and cooling speed of the furnace. The crystal was easily broken if the cooling rate was too fast. To avoid cracking, the temperature profile and the growth parameters had been optimized. The cleavage property of the GaAs crystal was strongly related to its atomic arrangement and corresponding electron density map. Ultrasonic vibration or mechanical machine would make the crystal cleaved along (110) plane. GaAs crystal displayed a strong anisotropic crack property under the force of microindentation test.

Abstract: Simulation and analysis of the converter transformer valve side’s transient electric field by finite element method is proposed. The electric field of converter transformer valve side’s is calculated under polarity reversal condition, the maximum value of the electric field intensity of insulating materials and the potential distribution of the before and after first polarity reversal are given, obtaining the electric field distribution characteristics of the oil-paper insulation material in the case of isotropic and anisotropic before and after the first polarity reversal, and made a comparison. The numerical calculation result of the converter transformer valve side’s electric field is also given, and the comparison of the calculation results in the case of isotropic and anisotropic, for before and after the first polarity reversal is analyzed, obtaining the variation rule of the converter transformer valve side’s electric field and the variable factors which affected the distribution of the electric field.

Abstract: In order to control the seepage and eliminate the adverse effects, influencing factors of drainage in engineering are discussed in this paper. The drainage holes are simulated by rod element to study the influence of drainage performance on angle and length. Compared the drainage performance of drainage galleries in different location, the optimal assembly is obtained. Meanwhile, drainage performance is analyzed by different permeability coefficient and anisotropy of rock and soil mass. The results show that: (1) Drainage flow of small angle and short drainage hole is close to big angle and long one, the small angle flows more than the big angle when increasing the same length. (2) Shallow drainage galleries can significantly drop the free surface and the deep one can greatly decrease the pore water pressure. Drainage galleries built at the upstream side and bottom, as the optimum assembly, can enormously change the seepage field. (3) For anisotropy materials, the horizontal drainage performance is better than vertical when Ky/Kx decreases. On the contrary, vertical is superior to the horizontal. Increasing vertical permeability coefficient is benefit to drainage.