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
The current research of rail corrugation mainly focuses on the mechanisms of its formation and development. Compared with the root causes and development mechanisms, the wheel-rail impacts, the fatigue failure of vehi...The current research of rail corrugation mainly focuses on the mechanisms of its formation and development. Compared with the root causes and development mechanisms, the wheel-rail impacts, the fatigue failure of vehicle-track parts, and the loss of ride comfort due to rail corrugation should also be taken into account. However, the influences of rail corrugation on vehicle and track vibration, and failure of vehicle and track structural parts are barely discussed in the literature. This paper presents an experimental and numerical investigation of the structural vibration of metro bogies caused by rail corrugation. Extensive experiments are conducted to investigate the effects of short-pitch rail corrugation on the vibration accelerations of metro bogies. A dynamic model of a metro vehicle coupled with a concrete track is established to study the influence of rail corrugation on the structural vibration of metro bogies. The field test results indicate that the short-pitch rail corrugation generates strong vibrations on the axle-boxes and the bogie frames, therefore, accelerates the fatigue failure of the bogie components. The numerical results show that short-pitch rail corrugation may largely reduce the fatigue life of the coil spring, and improving the damping value of the primary vertical dampers is likely to reduce the strong vibration induced by short-pitch rail corrugation. This research systematically studies the effect of rail corrugation on the vibration of metro bogies and proposes some remedies for mitigating strong vibrations of metro bogies and reducing the incidence of failure in primary coil springs, which would be helpful in developing new metro bogies and track maintenance procedures.展开更多
储能弹簧是变压器有载分接开关(on-load tap changer,OLTC)进行调压操作的关键部件,与OLTC的换挡过程成功与否密切相关。为准确识别储能弹簧的机械故障,文中从OLTC切换过程中振动信号的混沌特性出发,首先对振动信号进行了相空间重构,然...储能弹簧是变压器有载分接开关(on-load tap changer,OLTC)进行调压操作的关键部件,与OLTC的换挡过程成功与否密切相关。为准确识别储能弹簧的机械故障,文中从OLTC切换过程中振动信号的混沌特性出发,首先对振动信号进行了相空间重构,然后应用K-means++聚类算法对高维空间的相点进行了聚类分析,其中聚类时的类簇数目依据凝聚层次聚类法确定,据此定义了类间散度来定量描述OLTC振动信号的相点空间分布。以某组合式OLTC为测试对象,对其正常状态与存在不同磨损程度的储能弹簧故障时切换过程中的振动信号进行了测试。结果表明,合理的类簇数目能有效提高OLTC振动信号聚类分析的准确度,类间散度能准确识别OLTC储能弹簧的不同磨损程度,从而为OLTC机械状态的振动监测技术提供了重要依据。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Supported by National Natural Science Foundation of China(Grant Nos.U1361117,51305360)PhD Programs Foundation of Ministry of Education of China(Grant No.20130184110005)+1 种基金Cultivation Program for the Excellent Doctoral Dissertation of Southwest Jiaotong UniversityGuangzhou Metro Corporation Program of China
文摘The current research of rail corrugation mainly focuses on the mechanisms of its formation and development. Compared with the root causes and development mechanisms, the wheel-rail impacts, the fatigue failure of vehicle-track parts, and the loss of ride comfort due to rail corrugation should also be taken into account. However, the influences of rail corrugation on vehicle and track vibration, and failure of vehicle and track structural parts are barely discussed in the literature. This paper presents an experimental and numerical investigation of the structural vibration of metro bogies caused by rail corrugation. Extensive experiments are conducted to investigate the effects of short-pitch rail corrugation on the vibration accelerations of metro bogies. A dynamic model of a metro vehicle coupled with a concrete track is established to study the influence of rail corrugation on the structural vibration of metro bogies. The field test results indicate that the short-pitch rail corrugation generates strong vibrations on the axle-boxes and the bogie frames, therefore, accelerates the fatigue failure of the bogie components. The numerical results show that short-pitch rail corrugation may largely reduce the fatigue life of the coil spring, and improving the damping value of the primary vertical dampers is likely to reduce the strong vibration induced by short-pitch rail corrugation. This research systematically studies the effect of rail corrugation on the vibration of metro bogies and proposes some remedies for mitigating strong vibrations of metro bogies and reducing the incidence of failure in primary coil springs, which would be helpful in developing new metro bogies and track maintenance procedures.
文摘储能弹簧是变压器有载分接开关(on-load tap changer,OLTC)进行调压操作的关键部件,与OLTC的换挡过程成功与否密切相关。为准确识别储能弹簧的机械故障,文中从OLTC切换过程中振动信号的混沌特性出发,首先对振动信号进行了相空间重构,然后应用K-means++聚类算法对高维空间的相点进行了聚类分析,其中聚类时的类簇数目依据凝聚层次聚类法确定,据此定义了类间散度来定量描述OLTC振动信号的相点空间分布。以某组合式OLTC为测试对象,对其正常状态与存在不同磨损程度的储能弹簧故障时切换过程中的振动信号进行了测试。结果表明,合理的类簇数目能有效提高OLTC振动信号聚类分析的准确度,类间散度能准确识别OLTC储能弹簧的不同磨损程度,从而为OLTC机械状态的振动监测技术提供了重要依据。
