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A THERMO-PLASTIC/VISCOPLASTIC DAMAGE MODEL FOR GEOMATERIALS

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Acta Mechanica Solida Sinica 2011年第3期24卷 195-208页

作者： Hui Zhou Dawei Hu Fan Zhang Jianfu Shao State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China lml UMR 8107 CNRS-University of Lille I Villeneuve d＇Aseq France School of Civil Engineering and Architecture Hubei University of Technology Wuhan 430068 China

A thermo-plastic/viscoplastic damage coupled model was formulated to describe the time independent and time dependent behaviors of geomaterials under temperature effect. The plastic strain was divided into instantaneous plastic strain and creep plastic strain. To take temperature effect into acconnt, a temperature variable was introduced into the instantaneous and creep plastic behavior descriptions and damage characterization, and a linear thermal expansion law was used in constitutive equation formulation. According to the mechanical behavior of rock salt, a specific model was proposed based on the previous model and applied to Avery rock salt, in which the numerical results obtained from our model had a good agreement with the data from experiments.

关键词： thermo-plastic/viscoplastic damage coupled mechanical model geomaterial rocksalt

A HYDRO-MECHANICAL-CHEMICAL COUPLING MODEL FOR GEOMATERIAL WITH BOTH MECHANICAL AND CHEMICAL DAMAGES CONSIDERED

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Acta Mechanica Solida Sinica 2012年第4期25卷 361-376页

作者： Dawei Hu Hui Zhou Qizhi Hu Jianfu Shao Xiating Feng Haibin Xiao State Key Laboratory of Geomechanies and Geoteehnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China lml UMR8107CNRSUniversity of Lille IVilleneuve d'AscqFrance School of Civil Engineering and Architecture Hubei University of TechnologyWuhan 430068China Laneang River Hydropower Co. LtdKunming 650214China

A general framework of hydro-mechanical-chemical coupling model is proposed for geomaterial subjected to the dual effects of mechanical loading and chemical degradation. Mechanical damage due to microcracks in solid matrix and chemical damage induced by the increase of porosity due to dissolution of matrix minerals as well as their interactions are considered. A special model is proposed for sandstone. The reaction rate is formulated within the framework of mineral reaction kinetics and can thus take into account different dissolution mechanisms of three main mineral compositions under different pH values. The increase of porosity is physically defined by the dissolution of mineral composition and the chemical damage is related to the increase of porosity. The mechanical behavior is characterized by unified plastic damage and viscoplastic damage modeling. The effective stress is used for describing the effect of pore pressure. The elastic parameters and plastic evolution as well as viscoplastic evolution are dependent on chemical damage. The advection, which is coupled with mechanical damage and chemical damage, is considered as the dominant mechanism of mass transfer. The application of model proposed is from decoupled experiments to fully coupled experiment. The model offers a convenient approach to describing the hydro-mechanical-chemical coupled behavior of geomaterial.

关键词： hydro-mechanical-chemical coupling mechanical damage chemical damage sandstone chemical kinetics

Investigation of the fluid flow in an isolated rotor-stator system with a peripheral opening

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Science China(Physics,Mechanics & Astronomy) 2013年第4期56卷 745-754页

作者： DEBUCHY Roger ABDEL NOUR Fadi NAJI Hassane BOIS Gérard Laboratoire Génie Civil & géo-Environnement (LGCgE- EA 4515) UArtois/FSA Béthune F-62400 Béthune France Université Lille Nord de France F-59000 Lille France Damascus University Department of Water Engineering Damascus Syria lml-PRES Lille Nord de France Arts et Métiers ParisTech Lille France

This paper deals with an experimental, theoretical and numerical study of a turbulent flow with separated boundary layers between a rotor and a stator. The system is not subjected to any superimposed radial flow. The periphery of the cavity is opened to the atmosphere so that the solid body rotation for infinite discs is not always observed. Emphasis was placed on develop- ment of an asymptotic approach and a step-by-step method to compute the radial distribution of the core swirl ratio and the static pressure on the stator side. The theory also includes the radial and axial velocities in the core region. The numerical simulation has been conducted with the commercial CFD code Fluent 6.1. The k- SST turbulence model is used, with the assumption of 2D-axisymmetric and steady flow. CFD validations have been performed by comparison of the numerical results with the corresponding theoretical results. Numerical and experimental results are in good agreement with analytical solutions.

关键词： rotor-stator cavity analytical solution numerical simulations k- SST turbulence model

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径向导叶内流动分离特性的试验研究和控制

实验流体力学 2015年第6期29卷 48-53,78页

作者：司乔瑞袁寿其 Patrick Cherdieu Gérard Bois 江苏大学国家水泵及系统工程技术研究中心江苏镇江212013 法国国立高等工程技术大学lml实验室里尔59000

采用接触式探针和粒子图象测速技术(PIV)对导叶式离心泵径向导叶内流场的流动特性进行了研究。基于圆柱形微型三孔探针测试结果对5种流量下导叶的压力恢复能力进行了评估,测孔位置覆盖了导叶进出口截面和主线截面。压力恢复系数的理论... 详细信息

采用接触式探针和粒子图象测速技术(PIV)对导叶式离心泵径向导叶内流场的流动特性进行了研究。基于圆柱形微型三孔探针测试结果对5种流量下导叶的压力恢复能力进行了评估,测孔位置覆盖了导叶进出口截面和主线截面。压力恢复系数的理论值和试验值表明当流量大于导叶设计流量时导叶内产生了较大的静压损失。2C/2DPIV可视化试验的研究结果表明大流量下导叶叶片压力面发生了流动分离。设计了不同参数组合的涡流发生器来对流动分离现象进行控制,试验研究了6种方案对模型泵大流量工况下性能的影响,获得一组最佳方案,并分析了采用该方案后导叶内的流动特性。

关键词：离心泵径向导叶流动分离探针 PIV 涡流发生器

Tensile Properties and Fusion Zone Hardening for GMAW and MIEA Welds of a 7075-T651 Aluminum Alloy

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Acta Metallurgica Sinica(English Letters) 2014年第4期27卷 694-704页

作者： N.Alatorre R.R.Ambriz B.Noureddine A.Amrouche A.Talha D.Jaramillo Instituto Politcnico Nacional CIITEC-IPN Cerrada de Cecati S/N Col.Sta.CatarinaC.P 02250 AzcapotzalcoDFMexico Universit Lille Nord de France 59000 LilleFrance Universit Lille 1 LML59650 Villeneuve d’AscqFrance Laboratoire de Gnie Civil et ge'o-Environnement LGCgE EA 4515Facult des Sciences Appliques FSA BthuneUniversit d’ArtoisArrasFrance Ecole des Hautes Etudes d’Ingnieur (HEI) 13 rue de Toul59046 LilleFrance

Tensile and hardness values for 7075-T651 aluminum alloy in the as welded and post weld heat treated conditions（solubilization and artificial aging-T6）,obtained using GMAW and modified indirect electric arc（MIEA）welding processes are *** showed that the base material along rolling direction exhibited a tensile strength of around 600 MPa and elongation of 11%.For the as welded condition,tensile strength was 260 MPa and elongation percent of 3%.This behavior was attributed to brittleness induced by the microstructural characteristics of the welded alloys,as well as high *** profiles along the welds were obtained and different welded zones were identified.A soft zone（＊100 HV0.1） in the heat affected zone for GMAW and MIEA was observed,the minimum hardness corresponding to weld metal（＊85 and ＊96 HV0.1for GMAW and MIEA,respectively）.The high dilution between filler and base metal during welding in MIEA allows to the Zn and Cu to flow from the base metal into the weld metal,inducing hardening by solution and subsequent artificial *** this regard,the hardness of the weld metal for MIEA increases by 56%,while the tensile strength reaches a value close to 400 *** GMAW,non-favorable hardening effect was observed for the weld metal after solution and artificial aging.

关键词： Welding 7075-T651 Dilution fraction Tensile properties Fusion zone hardening

Hip Joint Forces Evaluation :Modelling and Experimental Methods.

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Hip Joint Forces Evaluation :Modelling and Experimental Meth...