Urban transportation systems are facing severe challenges due to the rapid growth of the urban population,especially in China.Suspended monorail system(SMS),as a sky rail transportation form,can effectively alleviate ...Urban transportation systems are facing severe challenges due to the rapid growth of the urban population,especially in China.Suspended monorail system(SMS),as a sky rail transportation form,can effectively alleviate urban traffic congestion due to its independent right-of-way and minimal ground footprint.However,the SMS possesses a special traveling system with unique vehicle structure and bridge configuration,which results in significant differences in both the mechanisms and dynamics problems associated with train–bridge interaction(TBI)when contrasted with those of traditional railway systems.Therefore,a thorough understanding of the SMS dynamics is essential for ensuring the operational safety of the system.This article presents a state-of-the-art review of the TBI modeling methodologies,critical dynamic features,field tests,and practice of the SMS in China.Firstly,the development history,technical features,and potential dynamics problems of the SMS are briefly described,followed by the mechanical characteristics and mechanisms of the train–bridge interactive systems.Then,the modeling methodology of the fundamental elements in the suspended monorail TBI is systematically reviewed,including the suspended train subsystem,bridge subsystem,train–bridge interaction relationships,system excitations,and solution method.Further,the typical dynamic features of the TBI under various operational scenarios are elaborated,including different train speeds,a variety of line sections,and a natural wind environment.Finally,the first new energy-based SMS test line in the world is systematically introduced,including the composition and functionality of the system,the details of the conducted field tests,and the measured results of the typical dynamic responses.At the end of the paper,both the guidance on further improvement of the SMS and future research topics are proposed.展开更多
In this work,a monorail vehicle-bridge coupling(VBC)model capable of accurately considering curve alignment and superelevation is established based on curvilinear moving coordinate system,to study the VBC vibration of...In this work,a monorail vehicle-bridge coupling(VBC)model capable of accurately considering curve alignment and superelevation is established based on curvilinear moving coordinate system,to study the VBC vibration of straddlemonorail curved girder bridge and the relevant factors influencing VBC.While taking Chongqing Jiao Xin line as an example,the VBC program is compiled using Fortran,where the reliability of algorithm and program is verified by the results of Chongqing monorail test.Moreover,the effects of curve radius,vehicle speed,and track irregularity on the corresponding vehicle and bridge vibrations are compared and analyzed.It is observed that the test results of lateral vibration acceleration(LVA)and vertical vibration acceleration(VVA)of track beam,and LVA of vehicle,are consistent with the simulation results.Owing to the track irregularity,vibration of track beam and vehicle increases significantly.Besides,an increase in vehicle speed gradually increases the vibration of track beam and vehicle.For the curve radius(R)≤200 m,lateral and vertical vibrations of the track beam and vehicle decrease significantly with an increasing curve radius.Alternatively,when 200 m<R<600 m,the lateral vibration of the track beamand vehicle decreases slowly with an increasing curve radius,while the relevant vertical vibration remains stable.Similarly,when R≥600 m,the lateral and vertical vibrations of the track beam and vehicle tend to be stable.Accordingly,the results presented here can provide a strong reference for the design,construction,and safety assessment of existing bridges.展开更多
The increased popularity of the private vehicle and the low budgets available to public-transport (PT) planners have meant that PT patronage has decreased significantly from what it once was. This has led to congestio...The increased popularity of the private vehicle and the low budgets available to public-transport (PT) planners have meant that PT patronage has decreased significantly from what it once was. This has led to congestion and pollution problems in many cities around the world. It is thus apparent that a new, high quality and sustainable PT system is needed to open the opportunity to attract more people to use PT. This work describes such a system called SkyCabs. The SkyCabs concept is comprised of many lightweight, driverless cabs running two ways on a single elevated monobeam. With each cab seating up to eight people, the aim is to create a feeling of personal travel, and by doing so increase the level of patronage on PT services. The SkyCabs system is investigated based on the following three criteria: a comparative analysis which involves researching and comparing system characteristics, a computer simulation analysing operational feasibility and an economic analysis which involves calculating and comparing the benefit-cost ratios for each mode analysed. A background section has been included to provide information on existing PT modes which have been compared to SkyCabs throughout this work. The SkyCabs concept has been deemed feasible within an urban context such as the North Shore of Auckland, New Zealand. This finding is based on a comparison with other options investigated and it is due to SkyCabs favourable characteristics, the high level of service offered and the low cost of implementation relative to return benefits.展开更多
A 20 degree of the freedom model of the micro-suspended monorail is established to analyze a new type of the vehicle system named micro-suspended monorail.The formula of the tire is established by using the magic form...A 20 degree of the freedom model of the micro-suspended monorail is established to analyze a new type of the vehicle system named micro-suspended monorail.The formula of the tire is established by using the magic formula.Through the modal analysis of the vehicle,the modes of the vehicle are obtained,and resonance has little effect on the vehicle.When the vehicle moves in a right turn curve,it yaws in the clockwise direction.Under the action of the guidewheel(stable wheel)force,the front bogie yaws clockwise but the rear one yaws counterclockwise.Moreover,the two bogies and the car body roll during the curve passing process of the vehicle.When the vehicle speed is high enough,the left drive wheel will derail and the anti-overturning moments are provided by the stable wheels.Then,the car body yaws in the counterclockwise direction when it moves out of the curve.In the simulation of the vehicle passing the curve,the clearance between the guide wheel and rail surface will lead to a fatal impact on the bogie.At the same time,the dynamic response of the vehicle under the crosswind is tested.The vehicle will not overturn due to the crosswind.Finally,the collision of adjacent vehicles is analyzed.The results show that there is an intermittent collision force between two vehicles due to the vehicle's non synchronous pitch motion.展开更多
The vibration behavior of the ground and houses caused by monorail traffic is discussed in this paper. The environmental ground vibration problem discussed herein occurs in a residential area near a monorail used for ...The vibration behavior of the ground and houses caused by monorail traffic is discussed in this paper. The environmental ground vibration problem discussed herein occurs in a residential area near a monorail used for public transportation, Vibrations were measured on the ground at the side of monorail piers lacing the residential area and within the affected houses. Results indicate that the vibration level in the house was 60 dB or more, a level high enough to warrant complaints, Peculiar geological and geographical features are thought to contribute to the amplification of low frequency （-10 Hz） ground vibrations to irritable levels in these homes even though a distance of≥30 m separates the residential area and the monorail.展开更多
Background and Objectives:The aims of this study were(1)to examine the diagnostic accuracy of resting timeaveraged distal coronary pressure(Pd)to mean aortic pressure(Pa)ratio to predict hyperemic fractional flow rese...Background and Objectives:The aims of this study were(1)to examine the diagnostic accuracy of resting timeaveraged distal coronary pressure(Pd)to mean aortic pressure(Pa)ratio to predict hyperemic fractional flow reserve(FFR)and(2)to identify a resting Pd/Pa value that can preclude the need for hyperemic FFR assessed with use of a monorail pressure catheter.Methods:A total of 191 stenoses were assessed.After exclusions,157 FFR data sets from 103 patients were analyzed.Results:Resting Pd/Pa showed poor agreement with hyperemic FFR(r=0.619,P<0.001).The receiver operating characteristic curve for resting Pd/Pa with reference to hyperemic FFR of 0.80 or less showed an area under the curve of 0.800(95%confi dence interval 0.732– 0.868,P<0.001),with the greatest diagnostic accuracy of 74.5%for resting Pd/Pa of less than 0.85.Resting Pd/Pa of 0.96 or greater had a sensitivity of 100%and a negative predictive value of 100%,and resting Pd/Pa of 0.82 or less had a specifi city of 98.9%and a positive predictive value of 94.1%to predict abnormal FFR of 0.80 or less.These results were consistent regardless of the vessels studied,the location of lesions,and the severity of stenosis.Conclusions:Resting Pd/Pa showed poor agreement with hyperemic FFR assessed with use of a monorail pressure microcatheter.However,resting Pd/Pa of 0.96 or greater had excellent sensitivity and negative predictive value to predict normal hyperemic FFR,and resting Pd/Pa of 0.82 or less had excellent specifi city and positive predictive value to predict abnormal hyperemic FFR.展开更多
The increased popularity of the private vehicle and the low budgets available to public-transport (PT) planners has meant that PT patronage has decreased significantly from what it once was. This has led to congestion...The increased popularity of the private vehicle and the low budgets available to public-transport (PT) planners has meant that PT patronage has decreased significantly from what it once was. This has led to congestion and pollution problems in many cities around the world. It is thus apparent that new, high quality and sustainable PT system is needed to open the opportunity to attract more people to use PT. This work describes such a system called SkyCabs. The SkyCabs concept is comprised of many, lightweight, driverless cabs running two ways on a single elevated monobeam. With each cab seating up to eight people, the aim is to create a feeling of personal travel, and in doing so increase the level of patronage on PT services. The SkyCabs system is investigated based on the following three criteria;a comparative analysis which involves researching and comparing system characteristics, a computer simulation analysing operational feasibility and an economic analysis which involves calculating and comparing the benefit-cost ratios for each mode analysed. A background section has been included to provide information on existing PT modes which have been compared to SkyCabs throughout this work. The SkyCabs concept has been deemed feasible within an urban context such as the North Shore of Auckland, New Zealand. This finding is based on a comparison with other options investigated and it is due to SkyCabs favourable characteristics, the high level of service offered and the low cost of implementation relative to return benefits.展开更多
The ageing of the population in Japan has become a problem. According to the research of different regions, where the ratio of the ageing population is above 25%, it is found that the Japanese society is gradually tur...The ageing of the population in Japan has become a problem. According to the research of different regions, where the ratio of the ageing population is above 25%, it is found that the Japanese society is gradually turned to hyper-aged society. The population along Kitakyushu monorail is also in such a situation. This study is based on the background, with excessive reliance on their own vehicles and public transport problems arising from the abolition of public transportation in Kitakyushu as the area of this study. Under the full consideration of people who can’t drive, the elderly who had to take buses as well as people who lack of transport ability where population decrease and the aging problem have been worsening, their surrounding environment should be further improved. In addition, it should be taken into consideration to increase the population in the walking distance around the stations.展开更多
At present, the mine auxiliary transportation equipment at home and abroad mainly include monorail crane, rail clamping vehicle, toothed rail vehicle and trackless rubber tyred vehicle. Compared with other models, mon...At present, the mine auxiliary transportation equipment at home and abroad mainly include monorail crane, rail clamping vehicle, toothed rail vehicle and trackless rubber tyred vehicle. Compared with other models, monorail crane has strong climbing ability and flexible operation. The locomotive can realize continuous direct transportation without transfer in changeable slope and multi turnout, and has strong adaptability to roadway deformation and is not affected by floor deformation. Ponding or material accumulation. According to the power type, the monorail crane mainly includes explosion-proof diesel engine monorail crane, battery monorail crane and pneumatic monorail crane. Among them, the diesel monorail spreader has the advantages of great flexibility, easy access to power source, no danger of electric shock, stable operation, low cost and so on. With the increasing number of extraction roadways in roadway engineering and the increasing design length of roadways, the use of diesel monorail crane can well solve the difficult problem of material transportation.展开更多
轨道梁作为跨座式单轨交通三大核心技术之一,其核心技术的创新与发展一直都是制约我国单轨交通发展的重要因素之一。结合“新型25 m PC轨道梁优化设计与制造工艺”课题,自主开发了“PC轨道梁配筋计算程序”和“PC轨道梁标准定型化设计...轨道梁作为跨座式单轨交通三大核心技术之一,其核心技术的创新与发展一直都是制约我国单轨交通发展的重要因素之一。结合“新型25 m PC轨道梁优化设计与制造工艺”课题,自主开发了“PC轨道梁配筋计算程序”和“PC轨道梁标准定型化设计软件”,并设计完成了跨座式单轨交通新型25 m PC轨道梁。通过智能软件自动生成25 m PC轨道梁的预应力钢筋和普通钢筋布置图,对轨道梁进行足尺25 m PC轨道梁静载、扭转、开裂、300万次疲劳和破坏试验验证。为验证新型25 m PC轨道梁优化设计与软件计算的正确性,将其试验数据与自制软件计算出的数据和理论数据进行对比。结果表明:软件自动设计的轨道梁,最大竖向挠度实测值为21.75 mm,校验系数为0.89,挠跨比为1/1122,而水平挠度实测值为2.36 mm,校验系数为0.72,满足规范要求;结合偏心及中心加载两种工况下试验结果,梁体应力差值在-0.51~0.61 MPa之间,扭转对直梁影响较小;开裂试验中,实测开裂荷载值为947 kN,实测重裂荷载为707 kN,由此得到梁体实际有效预应力975.26 MPa,实测值略大于设计有效预应力972.26 MPa,上述数据说明自动绘制的配筋图可以用于实际工程中。开发的智能软件对跨座式单轨交通轨道梁的智能建造提供技术支撑。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52202483,52108476,and 52388102)。
文摘Urban transportation systems are facing severe challenges due to the rapid growth of the urban population,especially in China.Suspended monorail system(SMS),as a sky rail transportation form,can effectively alleviate urban traffic congestion due to its independent right-of-way and minimal ground footprint.However,the SMS possesses a special traveling system with unique vehicle structure and bridge configuration,which results in significant differences in both the mechanisms and dynamics problems associated with train–bridge interaction(TBI)when contrasted with those of traditional railway systems.Therefore,a thorough understanding of the SMS dynamics is essential for ensuring the operational safety of the system.This article presents a state-of-the-art review of the TBI modeling methodologies,critical dynamic features,field tests,and practice of the SMS in China.Firstly,the development history,technical features,and potential dynamics problems of the SMS are briefly described,followed by the mechanical characteristics and mechanisms of the train–bridge interactive systems.Then,the modeling methodology of the fundamental elements in the suspended monorail TBI is systematically reviewed,including the suspended train subsystem,bridge subsystem,train–bridge interaction relationships,system excitations,and solution method.Further,the typical dynamic features of the TBI under various operational scenarios are elaborated,including different train speeds,a variety of line sections,and a natural wind environment.Finally,the first new energy-based SMS test line in the world is systematically introduced,including the composition and functionality of the system,the details of the conducted field tests,and the measured results of the typical dynamic responses.At the end of the paper,both the guidance on further improvement of the SMS and future research topics are proposed.
基金The authors gratefully acknowledge the partial support of this research by the Tianjin Natural Science Foundation(Nos.18JCQNJC08300,18JCYBJC90800)the National Natural Science Foundation of China(No.52108333)+4 种基金Tianjin Transportation Science and Technology Development Plan(2021-20)the Key Laboratory of Road Structure and Materials Transportation Industry(No.310821171114)the Innovation Capability Support Plan of Shaanxi Province(No.2019KJXX-036)the Scientific Research Project of Tianjin Education Commission(No.2020KJ038)the Department of Science and Technology of Shaanxi Province Focuses on Research and Development of General Project Industrial Field(No.2020GY318).
文摘In this work,a monorail vehicle-bridge coupling(VBC)model capable of accurately considering curve alignment and superelevation is established based on curvilinear moving coordinate system,to study the VBC vibration of straddlemonorail curved girder bridge and the relevant factors influencing VBC.While taking Chongqing Jiao Xin line as an example,the VBC program is compiled using Fortran,where the reliability of algorithm and program is verified by the results of Chongqing monorail test.Moreover,the effects of curve radius,vehicle speed,and track irregularity on the corresponding vehicle and bridge vibrations are compared and analyzed.It is observed that the test results of lateral vibration acceleration(LVA)and vertical vibration acceleration(VVA)of track beam,and LVA of vehicle,are consistent with the simulation results.Owing to the track irregularity,vibration of track beam and vehicle increases significantly.Besides,an increase in vehicle speed gradually increases the vibration of track beam and vehicle.For the curve radius(R)≤200 m,lateral and vertical vibrations of the track beam and vehicle decrease significantly with an increasing curve radius.Alternatively,when 200 m<R<600 m,the lateral vibration of the track beamand vehicle decreases slowly with an increasing curve radius,while the relevant vertical vibration remains stable.Similarly,when R≥600 m,the lateral and vertical vibrations of the track beam and vehicle tend to be stable.Accordingly,the results presented here can provide a strong reference for the design,construction,and safety assessment of existing bridges.
文摘The increased popularity of the private vehicle and the low budgets available to public-transport (PT) planners have meant that PT patronage has decreased significantly from what it once was. This has led to congestion and pollution problems in many cities around the world. It is thus apparent that a new, high quality and sustainable PT system is needed to open the opportunity to attract more people to use PT. This work describes such a system called SkyCabs. The SkyCabs concept is comprised of many lightweight, driverless cabs running two ways on a single elevated monobeam. With each cab seating up to eight people, the aim is to create a feeling of personal travel, and by doing so increase the level of patronage on PT services. The SkyCabs system is investigated based on the following three criteria: a comparative analysis which involves researching and comparing system characteristics, a computer simulation analysing operational feasibility and an economic analysis which involves calculating and comparing the benefit-cost ratios for each mode analysed. A background section has been included to provide information on existing PT modes which have been compared to SkyCabs throughout this work. The SkyCabs concept has been deemed feasible within an urban context such as the North Shore of Auckland, New Zealand. This finding is based on a comparison with other options investigated and it is due to SkyCabs favourable characteristics, the high level of service offered and the low cost of implementation relative to return benefits.
基金The National Key Research and Development Program of China(No.2018YFB1201702)the Program of State Key Laboratory of Traction Power(No.2018TPL_T11)the Fundamental Research Funds for the Central Universities(No.2682017CX009).
文摘A 20 degree of the freedom model of the micro-suspended monorail is established to analyze a new type of the vehicle system named micro-suspended monorail.The formula of the tire is established by using the magic formula.Through the modal analysis of the vehicle,the modes of the vehicle are obtained,and resonance has little effect on the vehicle.When the vehicle moves in a right turn curve,it yaws in the clockwise direction.Under the action of the guidewheel(stable wheel)force,the front bogie yaws clockwise but the rear one yaws counterclockwise.Moreover,the two bogies and the car body roll during the curve passing process of the vehicle.When the vehicle speed is high enough,the left drive wheel will derail and the anti-overturning moments are provided by the stable wheels.Then,the car body yaws in the counterclockwise direction when it moves out of the curve.In the simulation of the vehicle passing the curve,the clearance between the guide wheel and rail surface will lead to a fatal impact on the bogie.At the same time,the dynamic response of the vehicle under the crosswind is tested.The vehicle will not overturn due to the crosswind.Finally,the collision of adjacent vehicles is analyzed.The results show that there is an intermittent collision force between two vehicles due to the vehicle's non synchronous pitch motion.
文摘The vibration behavior of the ground and houses caused by monorail traffic is discussed in this paper. The environmental ground vibration problem discussed herein occurs in a residential area near a monorail used for public transportation, Vibrations were measured on the ground at the side of monorail piers lacing the residential area and within the affected houses. Results indicate that the vibration level in the house was 60 dB or more, a level high enough to warrant complaints, Peculiar geological and geographical features are thought to contribute to the amplification of low frequency （-10 Hz） ground vibrations to irritable levels in these homes even though a distance of≥30 m separates the residential area and the monorail.
文摘Background and Objectives:The aims of this study were(1)to examine the diagnostic accuracy of resting timeaveraged distal coronary pressure(Pd)to mean aortic pressure(Pa)ratio to predict hyperemic fractional flow reserve(FFR)and(2)to identify a resting Pd/Pa value that can preclude the need for hyperemic FFR assessed with use of a monorail pressure catheter.Methods:A total of 191 stenoses were assessed.After exclusions,157 FFR data sets from 103 patients were analyzed.Results:Resting Pd/Pa showed poor agreement with hyperemic FFR(r=0.619,P<0.001).The receiver operating characteristic curve for resting Pd/Pa with reference to hyperemic FFR of 0.80 or less showed an area under the curve of 0.800(95%confi dence interval 0.732– 0.868,P<0.001),with the greatest diagnostic accuracy of 74.5%for resting Pd/Pa of less than 0.85.Resting Pd/Pa of 0.96 or greater had a sensitivity of 100%and a negative predictive value of 100%,and resting Pd/Pa of 0.82 or less had a specifi city of 98.9%and a positive predictive value of 94.1%to predict abnormal FFR of 0.80 or less.These results were consistent regardless of the vessels studied,the location of lesions,and the severity of stenosis.Conclusions:Resting Pd/Pa showed poor agreement with hyperemic FFR assessed with use of a monorail pressure microcatheter.However,resting Pd/Pa of 0.96 or greater had excellent sensitivity and negative predictive value to predict normal hyperemic FFR,and resting Pd/Pa of 0.82 or less had excellent specifi city and positive predictive value to predict abnormal hyperemic FFR.
文摘The increased popularity of the private vehicle and the low budgets available to public-transport (PT) planners has meant that PT patronage has decreased significantly from what it once was. This has led to congestion and pollution problems in many cities around the world. It is thus apparent that new, high quality and sustainable PT system is needed to open the opportunity to attract more people to use PT. This work describes such a system called SkyCabs. The SkyCabs concept is comprised of many, lightweight, driverless cabs running two ways on a single elevated monobeam. With each cab seating up to eight people, the aim is to create a feeling of personal travel, and in doing so increase the level of patronage on PT services. The SkyCabs system is investigated based on the following three criteria;a comparative analysis which involves researching and comparing system characteristics, a computer simulation analysing operational feasibility and an economic analysis which involves calculating and comparing the benefit-cost ratios for each mode analysed. A background section has been included to provide information on existing PT modes which have been compared to SkyCabs throughout this work. The SkyCabs concept has been deemed feasible within an urban context such as the North Shore of Auckland, New Zealand. This finding is based on a comparison with other options investigated and it is due to SkyCabs favourable characteristics, the high level of service offered and the low cost of implementation relative to return benefits.
文摘The ageing of the population in Japan has become a problem. According to the research of different regions, where the ratio of the ageing population is above 25%, it is found that the Japanese society is gradually turned to hyper-aged society. The population along Kitakyushu monorail is also in such a situation. This study is based on the background, with excessive reliance on their own vehicles and public transport problems arising from the abolition of public transportation in Kitakyushu as the area of this study. Under the full consideration of people who can’t drive, the elderly who had to take buses as well as people who lack of transport ability where population decrease and the aging problem have been worsening, their surrounding environment should be further improved. In addition, it should be taken into consideration to increase the population in the walking distance around the stations.
文摘At present, the mine auxiliary transportation equipment at home and abroad mainly include monorail crane, rail clamping vehicle, toothed rail vehicle and trackless rubber tyred vehicle. Compared with other models, monorail crane has strong climbing ability and flexible operation. The locomotive can realize continuous direct transportation without transfer in changeable slope and multi turnout, and has strong adaptability to roadway deformation and is not affected by floor deformation. Ponding or material accumulation. According to the power type, the monorail crane mainly includes explosion-proof diesel engine monorail crane, battery monorail crane and pneumatic monorail crane. Among them, the diesel monorail spreader has the advantages of great flexibility, easy access to power source, no danger of electric shock, stable operation, low cost and so on. With the increasing number of extraction roadways in roadway engineering and the increasing design length of roadways, the use of diesel monorail crane can well solve the difficult problem of material transportation.
文摘轨道梁作为跨座式单轨交通三大核心技术之一,其核心技术的创新与发展一直都是制约我国单轨交通发展的重要因素之一。结合“新型25 m PC轨道梁优化设计与制造工艺”课题,自主开发了“PC轨道梁配筋计算程序”和“PC轨道梁标准定型化设计软件”,并设计完成了跨座式单轨交通新型25 m PC轨道梁。通过智能软件自动生成25 m PC轨道梁的预应力钢筋和普通钢筋布置图,对轨道梁进行足尺25 m PC轨道梁静载、扭转、开裂、300万次疲劳和破坏试验验证。为验证新型25 m PC轨道梁优化设计与软件计算的正确性,将其试验数据与自制软件计算出的数据和理论数据进行对比。结果表明:软件自动设计的轨道梁,最大竖向挠度实测值为21.75 mm,校验系数为0.89,挠跨比为1/1122,而水平挠度实测值为2.36 mm,校验系数为0.72,满足规范要求;结合偏心及中心加载两种工况下试验结果,梁体应力差值在-0.51~0.61 MPa之间,扭转对直梁影响较小;开裂试验中,实测开裂荷载值为947 kN,实测重裂荷载为707 kN,由此得到梁体实际有效预应力975.26 MPa,实测值略大于设计有效预应力972.26 MPa,上述数据说明自动绘制的配筋图可以用于实际工程中。开发的智能软件对跨座式单轨交通轨道梁的智能建造提供技术支撑。
