A coupled dynamics computation model for metro vehicles, along with a steel-spring floating-slab track, is developed based on the theory of vehicle-track coupled dynamics. Using the developed model, the influences of ...A coupled dynamics computation model for metro vehicles, along with a steel-spring floating-slab track, is developed based on the theory of vehicle-track coupled dynamics. Using the developed model, the influences of the thickness, length and mass of floating-slab, spring rate and its arrangement space, running speed, etc. on the time and frequency domain characteristics of steel-spring fulcrum force are analyzed. The applicability of steel-spring floatingslab track is discussed through two integrated example cases of metro and buildings possessing distinct natural vibra- tion characteristics. It is concluded that, it is quite significant, in the optimization modular design of the parameters of steel-spring floating-slab track, to take the matching relationship of both the amplitude-frequency characteristics of steel-spring fulcrum force and natural vibration characteristics of integrated structures into comprehensive consideration. In this way the expensive steel-spring floating-slab track can be economically and efficiently utilized according to the site condition, and at the same time, the economic losses and bad social impact resulted from the resonance during usage of steel-spring floating-slab track can be avoided.展开更多
Virtual simulation teaching is an addendum to the experimental teaching mode of railway engineering,and the two teaching methods complement each other and merge with each other.In view of the current research,there is...Virtual simulation teaching is an addendum to the experimental teaching mode of railway engineering,and the two teaching methods complement each other and merge with each other.In view of the current research,there is little discussion about the integration path of the two above.Based on the connotation and design of virtual simulation teaching,this research systematically expounds the integration of the real path and path optimization problems,and puts forward the railway engineering experimental teaching principles based on virtual simulation teaching.On the basis of this research,a virtual simulation experiment platform for vibration mechanics and its application in the floating slab vibration damping track was developed to make full use of three-dimensional modeling,virtual reality,human-computer interaction and other technologies,which can realistically simulate the vibration law and vibration damping effect of the rail transit system,and in the hope that the virtual simulation teaching can be widely used in the experimental teaching mode of railway engineering in the future.展开更多
The extensive use of steel spring floating slab tracks has effectively addressed the challenge of alleviating the environmental vibrations induced by urban rail transit systems.However,under the combined action of tra...The extensive use of steel spring floating slab tracks has effectively addressed the challenge of alleviating the environmental vibrations induced by urban rail transit systems.However,under the combined action of train dynamic loads and complex environmental factors,problems,such as the fracture of steel spring vibration isolators and suspension vibrations induced by the uneven settlement of the base,often occur.The failure of isolator support stiffness is often hidden in its early stages and is challenging to identify by conventional detection methods.At the same time,it will aggravate the wheel-rail interaction,accelerate the deterioration of track structure,and even affect the driving safety.This study first establishes a detailed coupled train-floating slab track-foundation analytical model.Then the influence of the vibration isolator support stiffness failure on the dynamic indices of the floating slab track system response is analyzed.A set of defect identification methods that can detect the number of failed steel springs,severity of damage,and their location is proposed.Finally,an intelligent monitoring system for support stiffness of floating slab track is built by combining the density-based spatial clustering of applications with noise algorithm and statistical data analysis and is applied to a rail line in southern China.During a three-year monitoring campaign,a suspension failure and a fracture of a steel spring were each successfully detected and detailed failure information was obtained.Field investigation results were consistent with the damage identification results.After repair,the track structure dynamic response returned to the average pre-damage level and further deterioration had been arrested.The proposed damage identification methods and monitoring system provide an approach for intelligent identification of track structure support stiffness failures.展开更多
为研究随机列车荷载作用下钢弹簧浮置板轨道(steel spring floating slab track,简称SSFST)上线运营后的减振效果,选取某地铁线路同一区间、同一曲线段内的普通无砟轨道及钢弹簧浮置板轨道典型测试断面,在同一天内开展了现场对比测试。...为研究随机列车荷载作用下钢弹簧浮置板轨道(steel spring floating slab track,简称SSFST)上线运营后的减振效果,选取某地铁线路同一区间、同一曲线段内的普通无砟轨道及钢弹簧浮置板轨道典型测试断面,在同一天内开展了现场对比测试。研究结果表明:钢弹簧浮置板轨道减振效果的线上评估结果与列车、轨道的实际运营状态直接相关;在不同列车的随机激励作用下,Z振级相对插入损失(ΔVL_(Z,max))相差超过10 dB,且部分测试样本无法满足特殊减振的设计需求;为获得保守的评价结果,应选择轮、轨平顺状态良好的运营区段开展对比测试;通过合理的养护维修,使运营列车及轨道保持良好的运行状态,是减振轨道区段满足振动控制需求的关键。展开更多
基金supported by the Key Project of Science and Technology in an Action of Shanghai Scientific and Technological Innovation (No. 09231201600)the National Natural Science Foundation of China(No. 50823004)the Science and Technology Department of Sichuan Province
文摘A coupled dynamics computation model for metro vehicles, along with a steel-spring floating-slab track, is developed based on the theory of vehicle-track coupled dynamics. Using the developed model, the influences of the thickness, length and mass of floating-slab, spring rate and its arrangement space, running speed, etc. on the time and frequency domain characteristics of steel-spring fulcrum force are analyzed. The applicability of steel-spring floatingslab track is discussed through two integrated example cases of metro and buildings possessing distinct natural vibra- tion characteristics. It is concluded that, it is quite significant, in the optimization modular design of the parameters of steel-spring floating-slab track, to take the matching relationship of both the amplitude-frequency characteristics of steel-spring fulcrum force and natural vibration characteristics of integrated structures into comprehensive consideration. In this way the expensive steel-spring floating-slab track can be economically and efficiently utilized according to the site condition, and at the same time, the economic losses and bad social impact resulted from the resonance during usage of steel-spring floating-slab track can be avoided.
基金The research is financially supported by First-class Undergraduate Course Funding Project in Hunan Province-Virtual Simulation Experimental Teaching Course(Xiang Jiao Tong[2021]No.28),Hunan Engineering Teaching Team)(Xiang Jiao Tong[2019]No.370)National Experimental Teaching Center of Civil Engineering Virtual Simulation(Central South University)Open Project(202001)Education and Teaching Reform Project of Central South University(2020jy063),which is gratefully acknowledged by the authors.
文摘Virtual simulation teaching is an addendum to the experimental teaching mode of railway engineering,and the two teaching methods complement each other and merge with each other.In view of the current research,there is little discussion about the integration path of the two above.Based on the connotation and design of virtual simulation teaching,this research systematically expounds the integration of the real path and path optimization problems,and puts forward the railway engineering experimental teaching principles based on virtual simulation teaching.On the basis of this research,a virtual simulation experiment platform for vibration mechanics and its application in the floating slab vibration damping track was developed to make full use of three-dimensional modeling,virtual reality,human-computer interaction and other technologies,which can realistically simulate the vibration law and vibration damping effect of the rail transit system,and in the hope that the virtual simulation teaching can be widely used in the experimental teaching mode of railway engineering in the future.
基金This work is supported by the National Natural Science Foundation of China(Nos.51978585 and 52008264)the Applied Basic Research Programs of Science and Technology Commission Foundation of Sichuan Province(No.2020YJ0214)+1 种基金the Foundation of High-speed Rail Joint Fund Key Projects of Basic Research(No.U1734207)the Foundation of National Engineering Laboratory for Digital Construction Evaluation Technology of Urban Rail Transit,China(No.2023JZ01).
文摘The extensive use of steel spring floating slab tracks has effectively addressed the challenge of alleviating the environmental vibrations induced by urban rail transit systems.However,under the combined action of train dynamic loads and complex environmental factors,problems,such as the fracture of steel spring vibration isolators and suspension vibrations induced by the uneven settlement of the base,often occur.The failure of isolator support stiffness is often hidden in its early stages and is challenging to identify by conventional detection methods.At the same time,it will aggravate the wheel-rail interaction,accelerate the deterioration of track structure,and even affect the driving safety.This study first establishes a detailed coupled train-floating slab track-foundation analytical model.Then the influence of the vibration isolator support stiffness failure on the dynamic indices of the floating slab track system response is analyzed.A set of defect identification methods that can detect the number of failed steel springs,severity of damage,and their location is proposed.Finally,an intelligent monitoring system for support stiffness of floating slab track is built by combining the density-based spatial clustering of applications with noise algorithm and statistical data analysis and is applied to a rail line in southern China.During a three-year monitoring campaign,a suspension failure and a fracture of a steel spring were each successfully detected and detailed failure information was obtained.Field investigation results were consistent with the damage identification results.After repair,the track structure dynamic response returned to the average pre-damage level and further deterioration had been arrested.The proposed damage identification methods and monitoring system provide an approach for intelligent identification of track structure support stiffness failures.
基金Project(2022YFB2603400) supported by the National Key R&D Program of ChinaProjects(52208449, 52108420) supported by the National Natural Science Foundation of ChinaProject(2022NSFSC1908) supported by the Natural Science Foundation of Sichuan Province,China。
