检索结果-南通市图书馆

In-plane dynamic Green's functions for inclined and uniformly distributed loads in a multi-layered transversely isotropic half-space

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2018年第2期17卷 293-309页

作者： Ba Zhenning Kang Zeqing Liang Jianwen Department of Civil Engineering Tianjin UniversityTianjin 300072China Key Laboratory of Coast Civil Structure Safety(Tianjin University) Tianjin 300072China

The dynamic stiffness method combined with the Fourier transform is utilized to derive the in-plane Green’s functions for inclined and uniformly distributed loads in a multi-layered transversely isotropic（TI）*** loaded layer is fixed to obtain solutions restricted in it and the corresponding reactions forces,which are then applied to the total system with the opposite *** adding solutions restricted in the loaded layer to solutions from the reaction forces,the global solutions in the wavenumber domain are obtained,and the dynamic Green’s functions in the space domain are recovered by the inverse Fourier *** presented formulations can be reduced to the isotropic case developed by Wolf（1985）,and are further verified by comparisons with existing solutions in a uniform isotropic as well as a layered TI halfspace subjected to horizontally distributed loads which are special cases of the more general problem *** deduced Green’s functions,in conjunction with boundary element methods,will lead to significant advances in the investigation of a variety of wave scattering,wave radiation and soil-structure interaction problems in a layered TI *** numerical results are given to investigate the influence of material anisotropy,frequency of excitation,inclination angle and layered on the responses of displacement and stress,and some conclusions are drawn.

关键词： Green's functions transversely isotropic medium multi-layered half-space stiffness method dynamic response

Numerical modeling of seismic wavefields in transversely isotropic media with a compact staggered-grid finite difference scheme

在线全文

学校读者我要写书评

暂无评论

Applied Geophysics 2009年第1期6卷 42-49,103页

作者：杜启振李宾侯波中国石油大学(华东)地球资源与信息学院山东东营257061 中国石油大学(北京)中国石油天然气集团公司物探重点实验室北京昌平102200

To deal with the numerical dispersion problem, by combining the staggeredgrid technology with the compact finite difference scheme, we derive a compact staggered- grid finite difference scheme from the first-order velocity-stress wave equations for the transversely isotropic media. Comparing the principal truncation error terms of the compact staggered-grid finite difference scheme, the staggered-grid finite difference scheme, and the compact finite difference scheme, we analyze the approximation accuracy of these three schemes using Fourier analysis. Finally, seismic wave numerical simulation in transversely isotropic （VTI） media is performed using the three schemes. The results indicate that the compact staggered-grid finite difference scheme has the smallest truncation error, the highest accuracy, and the weakest numerical dispersion among the three schemes. In summary, the numerical modeling shows the validity of the compact staggered-grid finite difference scheme.

关键词： transversely isotropic medium compact staggered-grid the first-order velocitystress wave equations numerical dispersion wave field simulation

Numerical simulation of elastic wave propagation based on the transversely isotropic BISQ equation

在线全文

学校读者我要写书评

暂无评论

Acta Seismologica Sinica(English Edition) 2002年第6期15卷 628-635页

作者：杨宽德杨顶辉王书强 DepartmentofMathematicalSciences TsinghuaUniversity

The Biot and Squirt-flow are the two most important mechanisms of fluid flow in the porous medium with fluids. Based on the BISQ (Biot-Squirt) model where the two mechanisms are treated simultaneously, dispersion and attenuation of elastic waves in the porous medium are widely investigated in recent years. However, we have not read any reports on numerical simulation based on the BISQ equation. In this paper, following the BISQ equation, elastic wave propagation in the transversely isotropic porous medium filled with fluids is simulated by the stag-gered grid method for different frequency and phase boundary cases and the two-layer medium. And propagating characteristics of seismic and acoustic waves and various phenomena occured in the propagating process are in-vestigated when the two mechanisms are considered simultaneously.

关键词： BISQ equation wave-fields simulation transversely isotropic medium staggered grid method

Design of protective and high sensitivity encapsulation layers in wearable devices

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第1期66卷 223-232页

作者： WANG XiuFeng HUANG JieLong LIU YangChengYi TAN JinYuan CHEN ShangDa AVILA Raudel XIE ZhaoQian School of Materials Science and Engineering Xiangtan UniversityXiangian 41105China Department of Mechanical Engineering Northwestern UniversityEvanstonIL 60208USA State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsDalian University of TechnologyDalian116024China

Elastomeric encapsulation layers are widely used in soft, wearable devices to physically isolate rigid electronic components from external environmental stimuli(e.g., stress) and facilitate device sterilization for reusability. In devices experiencing large deformations, the stress-isolation effect of the top encapsulation layer can eliminate the damage to the electronic components caused by external forces. However, for health monitoring and sensing applications, the strain-isolation effect of the bottom encapsulation layer can partially block the physiological signals of interest and degrade the measurement accuracy. Here, an analytic model is developed for the strain-and stress-isolation effects present in wearable devices with elastomeric encapsulation layers. The soft, elastomeric encapsulation layers and main electronic components layer are modeled as transversely isotropicelastic mediums and the strain-and stress-isolation effects are described using isolation indexes. The analysis and results show that the isolation effects strongly depend on the thickness, density, and elastic modulus of both the elastomeric encapsulation layers and the main electronic component layer. These findings, combined with the flexible mechanics design strategies of wearable devices, provide new design guidelines for future wearable devices to protect them from external forces while capturing the relevant physiological signals underneath the skin.

关键词： strain-isolation effect stress-isolation effect elastomeric encapsulation transversely isotropic medium wearable devices

Effect of anisotropy on thermoelastic contact problem

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2008年第4期29卷 501-510页

作者： Sakti Pada Barik M.Kanoria P.K.Chaudhuri Departmemt of Mathematics Gobardanga Hindu CollegeKhantura24-Parganas(N)West BengalIndia Department of Applied Mathematics University of Calcutta92A.P.C.RoadKolkata-700009India

This paper is concerned with the stationary plane contact of an insulated rigid punch and a half-space which is elastically anisotropic but thermally conducting. The frictional heat generation inside the contact region due to the sliding of the punch over the half-space surface and the heat radiation outside the contact region are taken into account. With the help of Fourier integral transform, the problem is reduced to a system of two singular integral equations. The equations are solved numerically by using Gauss-Jacobi and trapezoidal-rule quadratures. The effects of anisotropy and thermal effects are shown graphically.

关键词： transversely isotropic medium Fourier transform frictional heating punch heat radiation singular integral equation Fredholm integral equation