检索结果-南通市图书馆

Analytical Solutions of Cracks Emanating from an Elliptic Hole in an Infinite Plate under Tension

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第5期27卷 1057-1063页

作者： liu shuhong DUAN Shijie Department of Engineering Mechanics Shijiazhuang Tiedao University The Key Laboratory for Health Monitoring and Control of Large Structures of Hebei Province Department of Adult Education Shijiazhuang Tiedao University

It is a common phenomenon that the cracks originating from a hole can cause structural damage in ***,the fracture mechanics studies of hole edge crack problems are not *** problem of an elliptical hole with two collinear edge cracks of unequal length in an infinite plate under uniform tension at infinity is *** on the complex variable method,the analytical solutions of stress functions and stress intensity factors are *** stress distribution along the axes and the edge of the elliptical hole is given *** numerical results show that there is obvious stress concentration near the hole and cracks,and the stresses tend to applied loads at distances far from the defect,which conform to Saint-Venant’s ***,the stress functions are proved to be *** special conditions,the present configuration becomes the Griffith crack,two symmetrical cracks emanating from an elliptical hole,two cracks of unequal length emanating from a circular hole,a crack at the edge of a circular hole,or a crack emanating from an elliptical *** with available results,stress intensity factors for these special shapes of ellipses and cracks show good *** stress intensity factor for two cracks of unequal length at the edge of an elliptical hole increases with the crack length and the major-to-minor axis ratio of the elliptical *** stress distribution in an infinite plate containing an elliptic hole with unsymmetrical cracks is given for the first time.

关键词： hole crack stress distribution stress intensity factor

Exact Solutions for Piezoelectric Materials with an Elliptic Hole or a Crack under Uniform Internal Pressure

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2012年第4期25卷 845-852页

作者： liu shuhong SHEN Yingming liu Jinxi Department of Engineering Mechanics Shijiazhuang Tiedao University Shijiazhuang 050043 China Department of Science and Technology Shijiazhuang Tiedao University Shijiazhuang 050043 China

The existing investigations on piezoelectric materials containing an elliptic hole or a crack mainly focus on remote uniform tensile *** order to have a better understanding for the fracture behavior of piezoelectric materials under different loading conditions,theoretical and numerical solutions are presented for an elliptic hole or a crack in transversely isotropic piezoelectric materials subjected to uniform internal pressure and remote electro-mechanical *** the basis of the complex variable approach,analytical solutions of the elastic and electric fields inside and outside the defect are derived by satisfying permeable electric boundary condition at the surface of the elliptical *** an example of PZT-4 ceramics,numerical results of electro-elastic fields inside and outside the crack under various electric boundary conditions and electro-mechanical loads are given,and graphs of the electro-elastic fields in the vicinity of the crack tip are *** non-singular term is compared to the asymptotic one in the *** is shown that the dielectric constant of the air in the crack has no effect on the electric displacement component perpendicular to the crack,and the stresses in the piezoelectric material depend on the material properties and the mechanical loads on the crack surface and at infinity,but not on the electric loads at *** figures obtained are strikingly similar to the available *** the existing work,the existence of electric fields inside an elliptic hole or a crack is considered,and the piezoelectric solid is subjected to complicated electro-mechanical loads.

关键词： piezoelectric material elliptic hole crack boundary condition electro-elastic fields

Investigation of Anti-Plane Shear Behavior of a Piezoelectric Material Containing an Impermeable Edge Crack

在线全文

学校读者我要写书评

暂无评论

上海交通大学学报 2004年第z2期38卷 124-129页

作者： Shijie Duan shuhong liu Jin liu School of Adult Education Shijiazhuang Railway InstituteShijiazhuang 050043 China Department of Mechanics and Engineering Science Shijiazhuang Railway InstituteShijiazhuang 050043 China Department of Mechanics and Engineering Science Shijiazhuang Railway InstituteShijiazhuang 050043 China

The problem involving an edge-crack in a rectangular material under the anti-plane mechanical loading and in-plane electric loading is analyzed under the impermeable conditions. By using the series expansion, the general solutions of electromechanical fields are obtained, which satisfied both governing equations and crack sufrace boundary conditions, and the unknown constants in which can be obtained by the boundary collocation method. Numerical results are given to show the effect of electromechanical interaction on energy release rate.

关键词： piezoelectric material mode-Ⅲ edge-crack intensity factor energy release rate boundary collocation method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于数值模拟的青杆林滑坡稳定性分析及评价

山西建筑 2025年第1期51卷 89-93,116页

作者：刘书宏刘洪杨何成都大学建筑与土木工程学院四川成都610106 四川省第十二地质大队四川宜宾644002

滑坡是一种易发的地质灾害,会对自然环境、工程建筑等造成重大的破坏;开展对滑坡稳定性分析的研究是十分必要的。文章以自贡荣县青杆林滑坡为对象,在通过对滑坡现场调研的基础上,分析滑坡的变形破坏机制,并使用Geo-Studio进行数值模拟,... 详细信息

滑坡是一种易发的地质灾害,会对自然环境、工程建筑等造成重大的破坏;开展对滑坡稳定性分析的研究是十分必要的。文章以自贡荣县青杆林滑坡为对象,在通过对滑坡现场调研的基础上,分析滑坡的变形破坏机制,并使用Geo-Studio进行数值模拟,对其滑坡稳定性进行分析与评价。研究结果表明:青杆林滑坡在自然条件下属于基本稳定的状态,不易产生大规模的整体滑动变形,而在受到强降雨等不利因素的作用下,坡体的稳定性将进一步降低,易使滑坡处于欠稳定状态,从而失稳破坏。

关键词：滑坡变形机制稳定性分析 Geo-Studio

Flow-Induced Instabilities in Pump-Turbines in China

在线全文

学校读者我要写书评

暂无评论

Engineering 2017年第4期3卷 504-511页

作者： Zhigang Zuo shuhong liu State Key Laboratory of Hydro Science and Engineering Department of Thermal Engineering Tsinghua University Beijing 100084 China

The stability of pump-turbines is of great importance to the operation of pumped storage power （PSP） stations. Both hydraulic instabilities and operational instabilities have been reported in PSP stations in China. In order to provide a reference to the engineers and scientists working on pump-turbines, this paper summarizes the hydraulic instabilities and performance characteristics that promote the operational instabilities encountered in pump-turbine operations in China. Definitions, analytical methods, numerical and experimental studies, and main results are clarified. Precautions and countermeasures are also provided based on a literature review. The gaps between present studies and the need for engineering practice are pointed out.

关键词： Pump-turbines Flow-induced instability Pressure fluctuations S-shaped characteristics Positive slopes

Phase equilibria and crystal structure of ternary compounds in Al-rich corner of Al-Er-Y system at 673 and 873 K

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第1期60卷 128-138页

作者： Xiaoxu liu Yong Du shuhong liu Kaiming Cheng Zhihong Zhang State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials Advanced Materials InstituteQilu University of Technology(Shandong Academy of Sciences)Jinan250014China Inner Mongolia Niobium Metallurgical Engineering Laboratory Baotou Research Institute of Rare EarthsBaotou014030China

Phase equilibria in the Al-rich corner of the Al-Er-Y ternary system from 65 at.% to 100 at.% Al at 673 and873 K were investigated,and the two isothermal sections were established by X-ray diffraction(XRD),scanning electron microscope(SEM) and electron probe micro analysis(EPMA).Three ternary-phase regions are observed and the phase relations are similar at both isothermal *** are two ternary compounds,and a complete crystal structures and composition ranges of the two ternary compounds are determined as τ_(1)(Al_(75-76)Er_(15-22)Y_(2-10),R-3 m) and τ_(2)(Al_(75-76)Er_(11-17)Y_(7-14),P6_(3)/mmc) via XRD,focused ion beam coupled with transmission electron microscope(FIB-TEM) and ***,the solubilities of the third element in the binary compounds at both temperatures are *** solubility of Er inβ-Al_(3) Y phase reaches to 6.6 at.% and that of Y in Al_(3) Er phase reaches to 1.5 at.% after annealing at 873 *** temperature effect is not obvious for the phase equilibria at 673 and 873 K,but it increases the solubility of Er in β-Al_(3) Y,while it is not obvious for both the solubility of Y in Al_(3) Er and that of Er and Y in(Al).The phase equilibria of the Al-Er-Y ternary system determined by the present work have provided new phase diagram data for a future thermodynamic assessment of this system.

关键词： Aluminium alloy Phase equilibria Al-Er-Y XRD EPMA TEM

An optimization method on runner blades in bulb turbine based on CFD analysis

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2011年第2期54卷 338-344页

作者： YANG Wei WU YuLin liu shuhong Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China State Key Laboratory of Hydroscience and Engineering Department of Thermal Engineering Tsinghua University Beijing 100084 China

In this paper an optimization method of the runner blades in a bulb turbine based on CFD analysis is *** the method the main scales of the turbine including guide vane,runner and draft are *** the runner blades are modified based on the present *** the optimization method the runner blade is expressed by spline surface with a gather of coordinate *** B-spline curve is used to keep the modified blades *** order to make the blade optimization simple and ef- ficient,one of the coordinates is fixed and only the angles of the points are changed according to different modification *** main optimization principles based on flow diagnosis are presented *** three principles are all based on the CFD analysis of the internal flow in bulb *** the purpose of method verification,the optimization method is used in a model bulb turbine.A three dimensional steady turbulent computation is carried out through the whole passage including the bulb body,guide vanes,runner and draft tube of the bulb turbine under seven different work *** SST k-ωturbulence model is used during the CFD analysis and the performance of the turbine can be *** runner blade is optimized according to the three optimization principles based on flow *** CFD analysis is conducted again on the optimized turbine and another modification is needed if the new turbine can’t satisfy the required *** of the computational results between the original turbine and an optimized one indicates that the optimization method is practical and does improve the performance of the bulb turbine.

关键词： bulb turbine CFD flow diagnose performance prediction SST k-ω turbulence model B-spline curve

Viscous liquid sloshing damping in cylindrical container using a volume of fluid method

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2009年第6期52卷 1484-1492页

作者： Wei Yang shuhong liu Hong Lin Department of Thermal Engineering State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China Design and Research Institute of Launch Vehicle Beijing 100076 China

Liquid sloshing is a kind of very complicated free surface flow and exists widely in many *** order to calculate liquid sloshing damping precisely a volume of fluid method based on finite volume scheme is used to simulate free surface flows in partly filled cylindrical containers.A numerical method is pre-sented to simulate the movement of the free surface flow,in which a piecewise linear interface con-struction scheme and an unsplit Lagrangian advection scheme instead of Eulerian advection scheme are *** damping performance of liquid sloshing in cylindrical containers under fundamental sloshing mode is *** are four factors determining the surface-wave damping:free surface,boundary-layer,interior fluid and contact *** order to study different contributions from these four factors to whole damping,several examples are ***-slip and slip wall boundary conditions on both side wall and bottom wall of the cylindrical containers are studied to compare with the published results obtained by solving Stokes *** the present method the first three main factors can be *** simulation results show that the boundary-layer damping contribution increases while the interior fluid damping contribution decreases with increase of Reynolds number.

关键词： volume of fluid method unsplit Lagrangian advection scheme cylindrical container liquid sloshing damping

Electro-elastic Fields of Piezoelectric Materials with An Elliptic Hole under Uniform Internal Shearing Forces

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2013年第3期26卷 454-461页

作者： DU Yanliang liu shuhong DUAN Shijie LI Yanqiang Structural Health Monitoring and Control Institute Shijiazhuang Tiedao University Department of Engineering Mechanics Shijiazhuang Tiedao University Department of Adult Education Shijiazhuang Tiedao University

The existing investigations on piezoelectric materials containing an elliptic hole mainly focus on remote uniform tensile loads. In order to have a better understanding of the fracture behavior of piezoelectric materials under different loading conditions, theoretical and numerical solutions are presented for an elliptic hole in transversely isotropic piezoelectric materials subjected to uniform internal shearing forces based on the complex potential approach. By solving ten variable linear equations, the analytical solutions inside and outside the hole satisfying the permeable electric boundary conditions are obtained. Taking PZT-4 ceramic into consideration, numerical results of electro-elastic fields along the edge of the hole and axes, and the electric displacements in the hole are presented. Comparison with stresses in transverse isotropic elastic materials shows that the hoop stress at the ends of major axis in two kinds of material equals zero for the various ratios of major to minor axis lengths; If the ratio is greater than 1, the hoop stress in piezoelectric materials is smaller than that in elastic materials, and if the ratio is smaller than 1, the hoop stress in piezoelectric materials is greater than that in elastic materials; When it is a circle hole, the shearing stress in two materials along axes is the same. The distribution of electric displacement components shows that the vertical electric displacement in the hole and along axes in the material is always zero though under the permeable electric boundary condition; The horizontal and vertical electric displacement components along the edge of the hole are symmetrical and antisymmetrical about horizontal axis, respectively. The stress and electric displacement distribution tends to zero at distances far from the elliptical hole, which conforms to the conclusion usually made on the basis of Saint-Venant’s principle. Unlike the existing work, uniform shearing forces acting on the edge of the hole, an

关键词： piezoelectric material elliptic hole permeable boundary condition electro-elastic fields internal shearing forces