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Experimental study of dynamic mechanical properties of reactive powder concrete under high-strain-rate impacts

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Science China(Technological Sciences) 2010年第9期53卷 2435-2449页

作者： JU Yang1,2.LIU HongBin1,SHENG GuoHua1,3 & WANG HuiJie1 1 State Key Laboratory of Coal resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of Rocks and Concrete,China university of Mining and Technology,Beijing 100083,China 2.Department of Mechanical and Manufacturing {2.,university of Calgary,2.00 university Drive,AB T2. 1N4,Canada 3 school of resources and civil {2.,northeastern university,Shenyang 110004,China 1. State Key Laboratory of Coal resources and Safe Mining Beijing Key Laboratory of Fracture and Damage Mechanics of Rocks and Concrete China University of Mining and Technology Beijing 100083 China2. Department of Mechanical and Manufacturing Engineering University of Calgary 2500 University Drive AB T2N 1N4 Calgary Canada3. School of Resources and Civil Engineering Northeastern University Shenyang 110004 China

The dynamic mechanical properties of reactive powder concrete subjected to compressive impacts with high strain rates ranging from 10 to 1.1×102.s-1 were investigated by means of SHPB (split-Hopkinson-pressure-bar) tests of the cylindrical specimens with five different steel fiber volumetric *** properties of wave stress transmission,failure,strength,and energy consumption of RPC with varied fiber volumes and impact strain rates were *** influences of impact strain rates and fiber volumes on those properties were characterized as *** general forms of the dynamic stress-strain relationships of RPC were modeled based on the experimental *** investigations indicate that for the plain RPC the stress response is greater than the strain response,showing strong brittle *** RPC with a certain volume of fibers sustains higher strain rate impact and exhibits better deformability as compared with the plain *** a constant fiber fraction,the peak compressive strength,corresponding peak strain and the residual strain of the fiber-reinforced RPC rise by varying amounts when the impact strain rate increases,with the residual strain demonstrating the greatest *** the fiber content makes trivial contribution to improving the residual deformability of RPC when the impact strain rate is *** tests also show that the fiber content affects the peak compressive strength and the peak deformability of RPC in a different *** a constant impact strain rate and the fiber fraction less than 1.75%,the peak compressive strength rises with an increasing fiber *** peak compressive strength tends to decrease as the fiber volume exceeds 1.75%.The corresponding peak strain,however,incessantly rises with the increasing fiber *** total energy Edisp that RPC consumed during the period from the beginning of impacts to the time of residual strains elevates with the fiber volume increment as long as the fiber fraction

关键词： impact reactive powder concrete (RPC) high strain rate dynamic strength energy consumption dynamic stress-strain response

In situ experiments on width and evolution characteristics of excavation damaged zone in deeply buried tunnels

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Science China(Technological Sciences) 2011年第S1期54卷 167-174页

作者： LI ShaoJun 1,FENG XiaTing 1,LI ZhanHai 3,CHEN BingRui 1,JIANG Quan 1,WU ShiYong 2.HU Bin 2.&XU JinSong 2.1 State Key Laboratory of Geomechanics and Geotechinical engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China 2.Ertan Hydropower Development Company,Ltd.,Chengdu 610051,China 3 school of {2.s and civil engineering,northeastern university,Shenyang 110004,China 1. State Key Laboratory of Geomechanics and Geotechinical engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China3. School of Resources and Civil Engineering Northeastern University Shenyang 110004 China2. Ertan Hydropower Development Company Ltd. Chengdu 610051 China

The seven long tunnels of Jinping II hydropower station are deeply *** width and evolution characteristics of excavation damaged zone(EDZ) are the key problem to the design of tunnels excavation and *** order to study this problem,several specific experimental tunnels with different overburden and geometric sizes were excavated at this *** borehole camera,sliding micrometer,cross-hole acoustic wave equipment and acoustic emission apparatus were *** paper introduced the comprehensive in situ experimental methods through pre-installed facilities and pre-drilled *** properties of the surrounding rock mass,including cracks,deformation,elastic wave and micro fractures,were measured during the whole process of the tunnel *** width and characteristics of formation and evolution of tunnels EDZ were analyzed under different construction methods involving of TBM and drilling and blasting,the test tunnels were excavated by full-face or two *** relationships between EDZ and tunnel geometry sizes,overburden and excavation method were described as *** results will not only contribute a great deal to the analysis of rock mass behavior in deeply buried rock mass,but also provide direct data for support design and rockburst prediction.

关键词： deeply buried tunnel excavation damaged zone evolution characteristics in situ experiments

New Solution to Surface Temperature of Casting Slab Measurement Based on Preceded Reflector and Multi-Wavelength

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Journal of Iron and Steel Research International 2012年第8期19卷 12-16页

作者： LIU Jun1, MA Jiao-cheng2. YANG Feng3, XIAO Hui1, RAO Li-min1 (1. school of Nuclear engineering and Technology, East China Institute of Technology, Fuzhou 344000, Jiangxi, China 2. school of Mechanical engineering and Automation, northeastern university, Shenyang 110004, Liaoning, China 3. school of civil and Environmental engineering, East China Institute of Technology, Fuzhou 344000, Jiangxi, China) [a] school of Nuclear engineering and Technology East China Institute of Technology Fuzhou 344000 Jiangxi China [b] school of Mechanical engineering and Automation Northeastern University Shenyang 110004 Liaoning China [c] school of civil and Environmental {2. East China Institute of Technology Fuzhou 344000 Jiangxi China

The surface temperature of casting slab is an important parameter in the metallurgy field. Because the surface emissivity is uncertain and also unknown, it is difficult to measure the slab surface temperature accurately. A method based on preceded reflector and multi-wavelength was put forward to deal with the difficulty in surface temperature measurement of casting slab. On the premise of preceded reflector and non-preceded reflector, the method establishes the radiation energy equations and works out the emissivity and temperature in the equations. Also, the multilayer modeling of casting slab surface and multiple reflection-absorption process modeling were built by Monte Carlo method. The temperature measuring method had been applied in the continuous casting field. In order to verify the measured result, the thermal imaging method was adopted when the slab surface emissivity was set by repeated tests. Finally, the measured and verified temperature curves keep a same tendency and the error of the values is lower than 5℃. The comparison result shows that the method can measure temperature accurately.

关键词： casting slab emissivity surface temperature preceded reflector multi-wavelength

Vision navigation algorithm for mine agent based on quaternion

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中国有色金属学会会刊：英文版 2011年第S3期21卷 610-615页

作者： LI Ke-zhao1, 4, LEI Wei-wei1, 2. GUO Zeng-zhang1, 2. WU Li-xin3, ZHANG Qin4 1. school of Survey and Land Information engineering, Henan Polytechnic {2., Jiaozuo 454003, China 2. Key Laboratory of Mine Spatial Information Technologies of State Bureau of Surveying and Mapping, Henan Polytechnic {2., Jiaozuo 454003, China 3. College of resources and civil engineering, northeastern {2., Shenyang 110819, China 4. College of Geology engineering and Geomatics, Chang’an {2., Xi’an 710054, China [a] school of Survey and Land Information engineering Henan Polytechnic University Jiaozuo 454003 China [b] Key Laboratory of Mine Spatial Information Technologies of State Bureau of Surveying and Mapping Henan Polytechnic University Jiaozuo 454003 China [c] College of resources and civil {2. Northeastern University Shenyang 110819 China [d] College of Geology engineering and Geomatics Chang'an University Xi'an 710054 China

Autonomous relative navigation is the key technology in mining or rescuing. On the basis of mine requirement and the theories of machine vision, an autonomous relative navigation algorithm for mine agent based on quaternion was proposed. In rotation transformation, this algorithm was represented by using quaternion. Because the Jacobi matrix of this method is lower than that of Hall algorithm, the calculation efficiency is improved by using this algorithm. The results of these experiments show that the computation burden of this algorithm based on quaternion is about half that of Hall algorithm. This algorithm based on quaternion is improved as a valid way to solve the problem of mine real-time navigation.

关键词： quaternion mine agent vision navigation

Entropy Assessment on Environmental Influence of Condense Heat in Recovery System in Air-Conditioning Refrigerating Machine

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湖南大学学报（自然科学版） 2009年第S1期36卷 96-101页

作者： TANG Wen-wu1,2.WANG Han-qing1,2.1.school of Energy Science and engineering,Central South {2.,Changsha,Hunan 410083,China 2.school of civil engineering,Hunan {2. of Technology,Zhuzhou,Hunan 412.08,China) school of Energy Science and engineering Central South University Changsha 410083 China school of civil {2. Hunan University of Technology Zhuzhou 412008 China

This paper presented an entropy evaluation method for the influences of condense heat recovery system on the *** at the damage of the condense heat to the environment,an entropy of resource loss and an emission entropy from the condense heat recovery system in the air conditioning refrigerating machine were *** the evaluation of the entropies,we developed a new algorithm for the parameter identification,called the composite influence coefficient,based on the Least Squares Support Vector Machine *** simulation,the numerical experiments shows that the Least Squares Support Vector Machine method is one of the powerful methods for the parameter identification to compute the damage entropy of the condense heat,with the largest training error being-0.02.(the relative error being-3.56%),and the biggest test error being 0.015(the relative error being 2.5%).

关键词： air-conditioning refrigerating machine condense heat entropy evaluation LS-SVM

Dilatancy equation of rockfill material under the true triaxial stress condition

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Science China(Technological Sciences) 2011年第S1期54卷 175-184页

作者： XIAO Yang 1,2.LIU HanLong 1,2.ZHU JunGao 1,2.& SHI WeiCheng 1,3 1 Key Laboratory of Ministry of Education for Geomechanics and Embankment engineering,Hohai university,Nanjing 2.0098,China 2.Geotechnical Research Institute,Hohai university,Nanjing 2.0098,China 3 school of civil engineering and Architecture,Changzhou Institute of Technology,Changzhou 2.3002.China 1. Key Laboratory of Ministry of Education for Geomechanics and Embankment engineering Hohai University Nanjing 210098 China2. Geotechnical Research Institute Hohai University Nanjing 210098 China3. School of Civil Engineering and Architecture Changzhou Institute of Technology Changzhou 213002 China

Rockfill material is widely used for construction of high rockfill dam due to its facility,economical cost,high strength and effective aseismatic *** is provoked profoundly to propose a suitable constitutive model for a better application of this *** dilatancy equation of rockfill material plays a significant role in the constitutive *** the sake of simplicity,a dilatancy equation is established by the linear least square method on the basis of the rearranged data of rockfill material in the true triaxial *** on the fact that the rearranged data at different initial confining pressures are aligned in a narrow band,the dilatancy behavior of rockfill material is independent of the initial confining ***,different from the initial confining pressure,both the intermediate principal stress ratio and the specimen density exhibit a remarkable influence on the dilatancy behaviors of rockfill ***,the predictions of the proposed dilatancy equation are in a good agreement with the rearranged test data of rockfill material at different specimen densities and stress paths.

关键词： rockfill material dilatancy equation true triaxial test density stress path initial confining pressure

Numerical Modeling of Response and Damage of Masonry Walls to Blast Loading

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Transactions of Tianjin university 2006年第B9期12卷 132-137页

作者： DEEKS Andrew school of civil and {2. engineering The University of Western AustraliaAustralia

To model the damage process of masonry walls under blast loading, a dynamic continuum damage material model is constructed for brick and mortar separately. The degradation of both the stiffness and strength are governed by a damage variable. By using the proposed material model, damage and fragmentation of a typical masonry wall under blast loading at different scaled distances is calculated. The hazard level of the masonry wall to blast loading is evaluated by analyzing the numerical results.

关键词： masonry blast loading fragmentation hazard level damage numerical modeling

Mesh Size Effect in Numerical Simulation of Blast Wave Propagation and Interaction with Structures

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Transactions of Tianjin university 2008年第6期14卷 396-402页

作者：师燕超李忠献郝洪 school of civil {2. Tianjin University school of civil and {2. engineering The University of Western Australia

Numerical method is popular in analysing the blast wave propagation and interaction with ***,because of the extremely short duration of blast wave and energy trans-mission between different grids,the numerical results are sensitive to the finite element mesh *** numerical simulations show that a mesh size acceptable to one blast scenario might not be proper for another case,even though the difference between the two scenarios is very small,indicating a simple numerical mesh size convergence test might not be enough to guarantee accu-rate numerical ***,both coarse mesh and fine mesh were used in different blast scenarios to investigate the mesh size effect on numerical results of blast wave propagation and interaction with *** on the numerical results and their comparison with field test re-sults and the design charts in TM5-1300,a numerical modification method was proposed to correct the influence of the mesh size on the simulated *** can be easily used to improve the accu-racy of the numerical results of blast wave propagation and blast loads on structures.

关键词： mesh size effect numerical simulation sensitivity blast wave propagation blast load structures

Modelling of multi-bodies in close proximity under water waves——Fluid resonance in narrow gaps

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Science China(Physics,Mechanics & Astronomy) 2011年第1期54卷 16-25页

作者： LU Lin1,2.TENG Bin3,CHENG Liang 4,SUN Liang5 & CHEN XiaoBo6 1 Center for Deepwater engineering,Dalian university of Technology,Dalian 1{2.,China 2.State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian university of Technology,Dalian 1{2.,China 3 State Key Laboratory of Coastal and Offshore engineering,Dalian university of Technology,Dalian 1{2.,China 4 school of civil and resource engineering,The university of Western Australia,Crawly 6003,Australia 5 Centre for Offshore Research and engineering,Department of civil engineering,National university of Singapore,117576,Singapore 6 Research Department,Bureau Veritas,Neuilly-Sur-Seine,92.70,France 1. Center for Deepwater engineering Dalian University of Technology Dalian 116024 China2. State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China3. State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China4. School of Civil and Resource Engineering The University of Western Australia Crawly 6003 Australia5. Centre for Offshore Research and Engineering Department of Civil Engineering National University of Singapore Singapore 117576 Singapore6. Research Department Bureau Veritas Neuilly-Sur-Seine 92570 France

Viscous fluid model and potential flow model with and without artificial damping force(f=-μV,μ the damping coefficient and V the local averaging flow velocity) are employed in this work to investigate the phenomenon of fluid resonance in narrow gaps between multi-bodies in close proximity under water *** numerical results are compared with experimental data available in the *** comparison demonstrates that both the viscous fluid model and the potential flow model are able to predict the resonant frequency reasonably *** the conventional potential flow model(without artificial damping term) significantly over-predicts the wave height in narrow gaps around the resonant *** order to calibrate the appropriate damping coefficient used for the potential model and make it work as well as the viscous fluid model in predicting the resonant wave height in narrow gaps but with little computational efforts,the dependence of damping coefficient μ on the body geometric dimensions is examined considering the parameters of gap width Bg,body draft D,body breadth ratio Br and body number n(n = 2.3),where Br = BB/BA for the case of two bodies(Body A and Body B) with different breadths of BA and BB,*** was confirmed that the damping coefficient used for the potential flow model is not sensitive to the geometric dimensions and spatial *** was found that μ∈ [0.4,0.5] may guarantee the variation of Hg/H0 with kh to be generally in good agreement with the experimental data and the results of viscous fluid model,where Hg is the excited wave height in narrow gaps under various dimensionless incident wave frequencies kh,H0 is the incident wave height,k = 2./L is the wave number and h is the water depth.

关键词： narrow gap fluid resonance water wave viscous fluid model potential flow model finite element method boundary element method