检索结果-南通市图书馆

Landslide dynamic process and parameter sensitivity analysis by discrete element method: the case of Turnoff Creek rock avalanche

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 Mountain Science 2020年第7期17卷 1581-1595页

作者： An Hui-cong Ouyang Chao-jun Zhao Chuan Zhao Wei Key Laboratory of Mountain Hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu610041China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing100101China University of Chinese Academy of Sciences Beijing100049China Sichuan Academy of Water Conservancy Chengdu610072China

The great diversity and complexity of geological hazards in terms of flowing materials,environment,triggering mechanisms and physical processes during the flow bring great difficulties to the numerical parameter selection for the discrete element *** order to identity the significance of individual parameters on the landslides dynamic process and provide valuable contribution to the runout analysis of similar landslide,the dynamic process and associated microscopic mechanism of the Turnoff Creek rock avalanche in Canada are *** present numerical results are compared with the field survey data and the results of depth-integrated continuum *** final deposit range matches well with the field survey *** is illustrated that the discrete element method is robust and feasible to capture the dynamic characteristics of large rock avalanche over a complex ***,a new method to assess the landslide hazard level based on the discrete element method is *** to the parameter sensitivity analysis,it is demonstrated that the basal friction coefficient and bond strength are essential to the final deposit while rolling coefficient and restitution coefficient have little effects on it.

关键词： Discrete element method Contact model Numerical modeling Rock avalanche Geological hazard assessment parameter analysis

Seismic isolation analysis of FPS bearings in spatial lattice shell structures

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2010年第1期9卷 93-102页

作者： Yong-Chul Kim Xue Suduo Zhuang Peng Zhao Wei Li Chenghao Dongyang Structure Engineering Co. Ltd. Tanbang-dong 1014 Seo-gu Daejeon Korea 302-223 College of Architecture and Civil Engineering Beijing University of Technology Beijing 100124 China College of Civil and Traffic Engineering Beijing University of Civil Engineering and Architecture Beijing 100044 China Beijing Urban Engineering Design ＆ Research Institute Co. Ltd. Beijing 100037 China

A theoretical model of a friction pendulum system （FPS） is introduced to examine its application for the seismic isolation of spatial lattice shell structures. An equation of motion of the lattice shell with FPS bearings is developed. Then, seismic isolation studies are performed for both double-layer and single-layer lattice shell structures under different seismic input and design parameters of the FPS. The influence of frictional coefficients and radius of the FPS on seismic performance are discussed. Based on the study, some suggestions for seismic isolation design of lattice shells with FPS bearings are given and conclusions are made which could be helpful in the application of FPS.

关键词： seismic isolation friction pendulum system spatial structure lattice shell parameter analysis

Numerical investigation of dynamic stall suppression of rotor airfoil via improved co-flow jet

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第3期35卷 169-184页

作者： Jiaqi LIU Rongqian CHEN Yancheng YOU Zheyu SHI School of Aerospace Engineering Xiamen UniversityXiamen 361005China Rotor Aerodynamics Key Laboratory China Aerodynamics Research and Development CenterMianyang 621000China

The decrease in aerodynamic performance caused by the shock-induced dynamic stall of an advancing blade and the dynamic stall of a retreating blade at low speed and high angles of attack limits the flight speed of a ***,little research has been carried on the flow control methods employed to suppress both the dynamic stall induced by a shock wave and the dynamic stall occurring at high angles of *** dynamic stall suppression of a rotor airfoil by Co-Flow Jet(CFJ)is numerically investigated in this *** flowfield of the airfoil is simulated by solving Reynolds Averaged Navier-Stokes equations based on the sliding mesh ***,to improve the effect of a traditional CFJ on suppressing rotor airfoil shock-induced dynamic stall,an improved CFJ—a CFJ-sloping slot is *** shows that the CFJsloping slot suppresses the shock-induced dynamic stall more effectively than a traditional ***,the improved CFJ can also suppress the dynamic stall of rotor airfoil at low speed and high angles of *** improved CFJ proposed in this paper is an effective flow control method that simultaneously suppresses the dynamic stall of the advancing and retreating *** mechanism of the improved CFJ in suppressing the dynamic stall of the rotor airfoil is studied,and a comparison is made between the improved CFJ and the traditional CFJ in terms of dynamic stall suppression at high and low ***,the effect of improved CFJ parameters(the jet momentum coefficient,the position of the injection/suction slot,and the size of the injection/suction slot)on shock-induced dynamic stall suppression is analyzed.

关键词： Co-flow jet Dynamic stall Flow control parameter analysis Rotor airfoil

Performance of novel 3D printing tools in removing coronary-artery calcification tissue

在线全文

学校读者我要写书评

暂无评论

Bio-Design and Manufacturing 2023年第4期6卷 390-404页

作者： Chuhang Gao Zhaoju Zhu Zirui Huang Liujing Chen Lihong Lu Mingcheng Fang Yao Liu Bingwei He College of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350001China Fujian Engineering Research Center of Joint Intelligent Medical Engineering Fuzhou 350001China Maynooth International Engineering College Fuzhou UniversityFuzhou 350001China Shengli Clinical Medical College of Fujian Medical University Fuzhou 350001China Department of Cardiology Fujian Provincial HospitalFuzhou 350001China Advanced Manufacturing Technology of Shanxi Key Lab North UniversityTaiyuan 030051China

Rotational atherectomy is an effective treatment for severe vascular calcification obstruction,and relies on high-speed grinding(typically 130,000–210,000 r/min)with miniature grinding tools to remove calcified tissue and restore blood ***,reports of intraoperative complications are common because of the grinding force,temperature,and debris directly acting on the body during the grinding process,which can easily cause damage to *** this study,three novel grinding tools were designed and fabricated and a series of experiments have been conducted to analyze the effects of tool geometry and parameters on grinding performance,that is,force,temperature,and specimen surface *** results show that these tools can effectively remove simulated calcified tissue and that they have two motions,rotation and revolution,in the *** higher rotational speeds,grinding force and temperature increase noticeably,while the amount of debris decreases *** addition,by observing the surface morphology of the specimens,we concluded that the material removal rate per unit time is influenced by both rotational speed and tool geometry,and that high rotational speed and a rough tool surface can improve the material removal rate efficiently.

关键词： Rotational atherectomy Grinding tool Grinding performance parameter analysis

Analytical and numerical studies on the nonlinear dynamic response of orthotropic membranes under impact load

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2016年第4期15卷 657-672页

作者： Liu Changjiang Zheng Zhoulian Yang Xiaoyan State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology College of Environment and Civil Engineering Chengdu University of Technology College of Civil Engineering Chongqing University College of Nuclear Technology and Automation Engineering Chengdu University of Technology

Orthotropic membrane components and structures are widely used in building structures, instruments and meters, electronic engineering, space and aeronautics, etc., because of their light weights. However, the same lightweight combined with low stiffness make membranes prone to vibration under dynamic loads, and in some cases the vibration may lead to structural failure. Herein, the undamped nonlinear vibration response of pretension rectangular orthotropic membrane structures subjected to impact loading is studied by analytical and numerical methods. The analytical solution is obtained by solving the governing equations by the Bubnov-Galerkin method and the Lindstedt-Poincare perturbation method. Numerical analysis has also been carried out based on the same theoretical model. The analytical and numerical results have been compared and analyzed, and the influence of various model parameters on membrane vibration discussed. The results obtained herein provide some theoretical basis for the vibration control and dynamic design of orthotropic membrane components and structures.

关键词： membrane nonlinear vibration numerical analysis impact load parameter analysis

Geometrical nonlinear stability analyses of cable-truss domes

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University Science 2003年第3期4卷 317-323页

作者：高博青卢群鑫董石麟 DepartmentofCivilEngineering ZhejiangUniversityHangzhou310027China

The nonlinear finite element method is used to analyze the geometrical nonlinear stability of cable truss domes with different cable distributions. The results indicate that the critical load increases evidently when cables, especially diagonal cables, are distributed in the structure. The critical loads of the structure at different rise span ratios are also discussed in this paper. It was shown that the effect of the tensional cable is more evident at small rise span ratio. The buckling of the structure is characterized by a global collapse at small rise span ratio; that the torsional buckling of the radial truss occurs at big rise span ratio; and that at proper rise span ratio, the global collapse and the lateral buckling of the truss occur nearly simultaneously.

关键词： Cable truss dome Geometrical nonlinear stability analysis parameter analysis Cable distribution Critical load

Numerical Simulation Study of a Novel Horizontally Layered Enhanced Geothermal System:A Case Study of the Qiabuqia Geothermal Area,Qinghai Province,China

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2021年第4期30卷 1328-1340页

作者： GAO Kun LIU Weiqun MA Tianran HU Yang FANG Tian YE Lei School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou 221116China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

Hot dry rock,as a renewable and sustainable energy source,can alleviate resource shortages and environmental *** on data from the Qiabuqia geothermal field and an established thermal-hydrological-mechanical coupled mathematical model,a novel horizontally layered enhanced geothermal system(EGS)is proposed and compared with the conventional double vertical well *** the simulated conditions in this paper,the comprehensive heat recovery performance of the horizontally layered EGS is significantly better than that of the double vertical well ***,although the average production temperature of the double vertical well EGS is higher than that of the horizontally layered EGS in the attenuation stage,the heat power output of the horizontally layered EGS ranges from 6.10 MW to 12.25 MW,which is 1.36 to 1.67 times that of the double vertical well ***,the heat recovery rate of the horizontally layered EGS is 6.63%higher than that of the double vertical well EGS and is thus more ***,parametric analysis was performed to investigate the influence of the controllable parameters on heat recovery for the horizontally layered *** heat power output and heat extraction ratio are proportional to the pressure difference and well spacing and inversely proportional to the injection fluid *** thermal power output is most greatly influenced by the pressure difference,followed by the well spacing and injection fluid *** effects of the pressure difference and well spacing on the heat recovery rate are almost the same,and the injection fluid temperature has no effect.

关键词： hot dry rock enhanced geothermal system thermal-hydrological-mechanical coupling numerical simulation parameter analysis

Characterization of Surface Hardness and Microstructure of High Performance Concrete

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2018年第1期33卷 124-132页

作者：杨永敢张云升 SHE Wei School of Materials Science and Engineering Southeast University

The relationship between compressive strength obtained by universal testing machine and rebound value obtained by the hammer of high performance concrete was systematically investigated at the macro level. And a model of high performance concrete strength curve was established from them. At the micro level, the microstructure, hydration products and pore structure of concrete surface were analyzed by scanning electron microscopy（SEM）, comprehensive thermal analysis（TG-DSC） and mercury intrusion porosimetry（MIP）, respectively. The effect of carbonation on surface strength was also investigated. The results showed that the concrete surface hardness layer grew rapidly at early stage and then stabilized at last with ongoing curing age; the rebound value and compressive strength of concrete with slag were higher than those of concrete with the same content of fly ash. In addition, the strength curve obtained by the least square method can satisfy the local standard requirements with an average relative error of 8.9% and a relative standard deviation of 11.3%. When the carbonation depth was 6 mm, the compressive strength calculated by national uniform strength curve was 25 PMa higher than that by high performance concrete.

关键词： high performance concrete rebound test parameter analysis strength curve

Sensitivity analysis for parameters of a monitoring system for steep slopes of open-pit mines

在线全文

学校读者我要写书评

暂无评论

Mining Science and Technology 2009年第4期19卷 441-445页

作者： HAN Xue HE Man-chao ZHANG Bi College of Architecture and Civil Engineering Heilongjiang Institute of Science and Technology Harbin Heilongjiang 150027 China School of Mechanics ＆ Civil Engineering China University of Mining ＆ Technology Beijing 100083 China

Monitoring the stability of steep slopes of open-pit mines is a major issue relating to production safety in *** order to determine the technical parameters of a new type of supervising system applied in monitoring steep slopes of open-pit mines,the MSARMA method was used to establish analytical models for the monitoring system,given various parameter settings based on the description of mechanical monitoring *** used this sensitivity analysis to conclude that the setting of the most sensitive location of a mechanical monitoring system should be within a range of 1/5～1/2 of the lower part in a vertical direction of steep slopes,with a rational and feasible range of the dip angle setting between 0°～20°.Given the analytical results of our on-site experiments,we have shown that the parameters determined reflect the stability of steep slopes accurately and *** conclusions provide a basis for the application of a new type of steep slope stability monitoring technology in open-pit mines.

关键词： open-pit mine steep slope monitoring system setting parameter analysis