The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Zhiping Zeng - One of the best experts on this subject based on the ideXlab platform.
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formulation of three dimensional equations of motion for train Slab Track bridge interaction system and its application to random vibration analysis
Applied Mathematical Modelling, 2016Co-Authors: Zhiping Zeng, Fusha Liu, Ping Lou, Yangang Zhao, Limi PengAbstract:Abstract This study presents the formulation of three-dimensional equations of motion for a train–Slab Track–bridge interaction system and its application to random vibration analysis using the finite element and pseudo-excitation methods. In this study, a train, Slab Track, and bridge are regarded as an integrated system, each vehicle is modeled as a four-wheelset mass-spring-damper system with a two-layer suspension system at 23 degrees of freedom, and the rail, Slab, girder, and pier are modeled as elastic Bernoulli–Euler beams connected with each other by discrete or continuous spring and damper elements. Three-dimensional equations of motion for the entire system are derived using the energy principle. Dynamic contact forces between moving vehicles and rails are considered as internal forces, and thus, the excitation vectors of load between a wheel and rail, induced by a vehicle's weight and random Track irregularities, are easily formulated using the pseudo-excitation method. These equations can be solved by a step-by-step integration method to simultaneously obtain the random dynamic responses of the system. The three-dimensional random vibration characteristics of the system are investigated using an example of a nine-span simply supported beam bridge on which a train consisting of 8 cars travels.
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random vibration analysis of train bridge under Track irregularities and traveling seismic waves using train Slab Track bridge interaction model
Journal of Sound and Vibration, 2015Co-Authors: Zhiping Zeng, Yangang Zhao, Lingku Che, Ping LouAbstract:Abstract The frequent use of bridges in high-speed railway lines greatly increases the probability that trains are running on bridges when earthquakes occur. This paper investigates the random vibrations of a high-speed train traversing a Slab Track on a continuous girder bridge subjected to Track irregularities and traveling seismic waves by the pseudo-excitation method (PEM). To derive the equations of motion of the train–Slab Track–bridge interaction system, the multibody dynamics and finite element method models are used for the train and the Track and bridge, respectively. By assuming Track irregularities to be fully coherent random excitations with time lags between different wheels and seismic accelerations to be uniformly modulated, non-stationary random excitations with time lags between different foundations, the random load vectors of the equations of motion are transformed into a series of deterministic pseudo-excitations based on PEM and the wheel–rail contact relationship. A computer code is developed to obtain the time-dependent random responses of the entire system. As a case study, the random vibration characteristics of an ICE-3 high-speed train traversing a seven-span continuous girder bridge simultaneously excited by Track irregularities and traveling seismic waves are analyzed. The influence of train speed and seismic wave propagation velocity on the random vibration characteristics of the bridge and train are discussed.
Yangang Zhao - One of the best experts on this subject based on the ideXlab platform.
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formulation of three dimensional equations of motion for train Slab Track bridge interaction system and its application to random vibration analysis
Applied Mathematical Modelling, 2016Co-Authors: Zhiping Zeng, Fusha Liu, Ping Lou, Yangang Zhao, Limi PengAbstract:Abstract This study presents the formulation of three-dimensional equations of motion for a train–Slab Track–bridge interaction system and its application to random vibration analysis using the finite element and pseudo-excitation methods. In this study, a train, Slab Track, and bridge are regarded as an integrated system, each vehicle is modeled as a four-wheelset mass-spring-damper system with a two-layer suspension system at 23 degrees of freedom, and the rail, Slab, girder, and pier are modeled as elastic Bernoulli–Euler beams connected with each other by discrete or continuous spring and damper elements. Three-dimensional equations of motion for the entire system are derived using the energy principle. Dynamic contact forces between moving vehicles and rails are considered as internal forces, and thus, the excitation vectors of load between a wheel and rail, induced by a vehicle's weight and random Track irregularities, are easily formulated using the pseudo-excitation method. These equations can be solved by a step-by-step integration method to simultaneously obtain the random dynamic responses of the system. The three-dimensional random vibration characteristics of the system are investigated using an example of a nine-span simply supported beam bridge on which a train consisting of 8 cars travels.
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random vibration analysis of train bridge under Track irregularities and traveling seismic waves using train Slab Track bridge interaction model
Journal of Sound and Vibration, 2015Co-Authors: Zhiping Zeng, Yangang Zhao, Lingku Che, Ping LouAbstract:Abstract The frequent use of bridges in high-speed railway lines greatly increases the probability that trains are running on bridges when earthquakes occur. This paper investigates the random vibrations of a high-speed train traversing a Slab Track on a continuous girder bridge subjected to Track irregularities and traveling seismic waves by the pseudo-excitation method (PEM). To derive the equations of motion of the train–Slab Track–bridge interaction system, the multibody dynamics and finite element method models are used for the train and the Track and bridge, respectively. By assuming Track irregularities to be fully coherent random excitations with time lags between different wheels and seismic accelerations to be uniformly modulated, non-stationary random excitations with time lags between different foundations, the random load vectors of the equations of motion are transformed into a series of deterministic pseudo-excitations based on PEM and the wheel–rail contact relationship. A computer code is developed to obtain the time-dependent random responses of the entire system. As a case study, the random vibration characteristics of an ICE-3 high-speed train traversing a seven-span continuous girder bridge simultaneously excited by Track irregularities and traveling seismic waves are analyzed. The influence of train speed and seismic wave propagation velocity on the random vibration characteristics of the bridge and train are discussed.
Shengyang Zhu - One of the best experts on this subject based on the ideXlab platform.
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interface damage assessment of railway Slab Track based on reliability techniques and vehicle Track interactions
Journal of Transportation Engineering-asce, 2016Co-Authors: Shengyang Zhu, Chengbiao Cai, Wanming ZhaiAbstract:AbstractThe interface damage as one of the most critical damage issues in railway Slab Tracks is evaluated in this work on the basis of reliability techniques and vehicle-Track interactions. First, a coupled dynamics model of a vehicle and the Slab Track is developed involving nonlinear spring-damper elements for simulation of the interface damage. Furthermore, considering the random nature of the damage length, the damage height, the rail pad stiffness, and the elastic modulus of cement asphalt (CA) mortar layer, explicit mathematical expressions between the input stochastic variables and output dynamic responses are obtained on the basis of the combination of the response surface method (RSM) and the dynamic simulations of vehicle-Track system. Subsequently, Monte Carlo (MC) simulations are performed for the probability analysis by directly using the response surface functions. Finally, by adopting the amplification factor (AF) of the dynamic response as the control indices, the damage assessment criter...
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stress intensity factors evaluation for through transverse crack in Slab Track system under vehicle dynamic load
Engineering Failure Analysis, 2014Co-Authors: Shengyang Zhu, Chengbiao CaiAbstract:The stress intensity factors (SIFs) for through-transverse crack in the China Railway Track System (CRTS II) Slab Track system under vehicle dynamic load are evaluated in this paper. A coupled dynamic model of a half-vehicle and the Slab Track is presented in which the half-vehicle is treated as a 18-degree-of-freedom multi-body system. The Slab Track is modeled as two continuous Bernoulli–Euler beams supported by a series of elastic rectangle plates on a viscoelastic foundation. The model is applied to calculate the vertical and lateral dynamic wheel–rail forces. A three-dimensional finite element model of the Slab Track system is then established in which the through-transverse crack at the bottom of concrete base is created by using extended finite element method (XFEM). The wheel–rail forces obtained by the vehicle-Track dynamics calculation are utilized as the inputs to finite element model, and then the values of dynamic SIFs at the crack-tip are extracted from the XFEM solution by domain based interaction integral approach. The influences of subgrade modulus, crack length, crack angle, friction coefficient between cracked surfaces, and friction coefficient between faces of concrete base and subgrade on dynamic SIFs are investigated in detail. The analysis indicates that the subgrade modulus, crack length and crack angle have great effects on dynamic SIFs at the crack-tip, while both of the friction coefficients have negligible influences on variations of dynamic SIFs. Also the statistical characteristics of varying SIFs due to random wheel–rail forces are studied and results reveal that the distributions of dynamic SIFs follow an approximately Gaussian distribution with different mean values and standard deviations. The numerical results obtained are very useful in the maintenance of the Slab Track system.
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interface damage and its effect on vibrations of Slab Track under temperature and vehicle dynamic loads
International Journal of Non-linear Mechanics, 2014Co-Authors: Shengyang Zhu, Chengbiao CaiAbstract:Abstract This paper presents a three-dimensional finite element model to investigate the interface damage occurred between prefabricated Slab and CA (cement asphalt) mortar layer in the China Railway Track System (CRTS-II) Slab Track system. In the finite element model, a cohesive zone model with a non-linear constitutive law is introduced and utilized to model the damage, cracking and delamination at the interface. Combining with the temperature field database obtained from the three-dimensional transient heat transfer analysis, the interface damage evolution as a result of temperature change is analyzed. A three-dimensional coupled dynamic model of a vehicle and the Slab Track is then established to calculate the varying rail-supporting forces which are utilized as the inputs to the finite element model. The non-linearities of the wheel–rail contact geometry, the wheel–rail normal contact force and the wheel–rail tangential creep force are taken into account in the model. Setting the maximum interface damaged state calculated under temperature change as the initial condition, the interface damage evolution and its influence on the dynamic response of the Slab Track are investigated under the joint action of the temperature change and vehicle dynamic load. The analysis indicates that the proposed model is capable of predicting the initiation and propagation of cracks at the interface. The prefabricated Slab presents lateral warping, resulting in severe interface damage on both the sides of the Slab Track along the longitudinal direction during temperature drop process, while the interface damage level does not change significantly under vehicle dynamic loads. The interface damage has great effects on the dynamic responses of the Slab Track.
Limi Peng - One of the best experts on this subject based on the ideXlab platform.
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formulation of three dimensional equations of motion for train Slab Track bridge interaction system and its application to random vibration analysis
Applied Mathematical Modelling, 2016Co-Authors: Zhiping Zeng, Fusha Liu, Ping Lou, Yangang Zhao, Limi PengAbstract:Abstract This study presents the formulation of three-dimensional equations of motion for a train–Slab Track–bridge interaction system and its application to random vibration analysis using the finite element and pseudo-excitation methods. In this study, a train, Slab Track, and bridge are regarded as an integrated system, each vehicle is modeled as a four-wheelset mass-spring-damper system with a two-layer suspension system at 23 degrees of freedom, and the rail, Slab, girder, and pier are modeled as elastic Bernoulli–Euler beams connected with each other by discrete or continuous spring and damper elements. Three-dimensional equations of motion for the entire system are derived using the energy principle. Dynamic contact forces between moving vehicles and rails are considered as internal forces, and thus, the excitation vectors of load between a wheel and rail, induced by a vehicle's weight and random Track irregularities, are easily formulated using the pseudo-excitation method. These equations can be solved by a step-by-step integration method to simultaneously obtain the random dynamic responses of the system. The three-dimensional random vibration characteristics of the system are investigated using an example of a nine-span simply supported beam bridge on which a train consisting of 8 cars travels.
Chengbiao Cai - One of the best experts on this subject based on the ideXlab platform.
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interface damage assessment of railway Slab Track based on reliability techniques and vehicle Track interactions
Journal of Transportation Engineering-asce, 2016Co-Authors: Shengyang Zhu, Chengbiao Cai, Wanming ZhaiAbstract:AbstractThe interface damage as one of the most critical damage issues in railway Slab Tracks is evaluated in this work on the basis of reliability techniques and vehicle-Track interactions. First, a coupled dynamics model of a vehicle and the Slab Track is developed involving nonlinear spring-damper elements for simulation of the interface damage. Furthermore, considering the random nature of the damage length, the damage height, the rail pad stiffness, and the elastic modulus of cement asphalt (CA) mortar layer, explicit mathematical expressions between the input stochastic variables and output dynamic responses are obtained on the basis of the combination of the response surface method (RSM) and the dynamic simulations of vehicle-Track system. Subsequently, Monte Carlo (MC) simulations are performed for the probability analysis by directly using the response surface functions. Finally, by adopting the amplification factor (AF) of the dynamic response as the control indices, the damage assessment criter...
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stress intensity factors evaluation for through transverse crack in Slab Track system under vehicle dynamic load
Engineering Failure Analysis, 2014Co-Authors: Shengyang Zhu, Chengbiao CaiAbstract:The stress intensity factors (SIFs) for through-transverse crack in the China Railway Track System (CRTS II) Slab Track system under vehicle dynamic load are evaluated in this paper. A coupled dynamic model of a half-vehicle and the Slab Track is presented in which the half-vehicle is treated as a 18-degree-of-freedom multi-body system. The Slab Track is modeled as two continuous Bernoulli–Euler beams supported by a series of elastic rectangle plates on a viscoelastic foundation. The model is applied to calculate the vertical and lateral dynamic wheel–rail forces. A three-dimensional finite element model of the Slab Track system is then established in which the through-transverse crack at the bottom of concrete base is created by using extended finite element method (XFEM). The wheel–rail forces obtained by the vehicle-Track dynamics calculation are utilized as the inputs to finite element model, and then the values of dynamic SIFs at the crack-tip are extracted from the XFEM solution by domain based interaction integral approach. The influences of subgrade modulus, crack length, crack angle, friction coefficient between cracked surfaces, and friction coefficient between faces of concrete base and subgrade on dynamic SIFs are investigated in detail. The analysis indicates that the subgrade modulus, crack length and crack angle have great effects on dynamic SIFs at the crack-tip, while both of the friction coefficients have negligible influences on variations of dynamic SIFs. Also the statistical characteristics of varying SIFs due to random wheel–rail forces are studied and results reveal that the distributions of dynamic SIFs follow an approximately Gaussian distribution with different mean values and standard deviations. The numerical results obtained are very useful in the maintenance of the Slab Track system.
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interface damage and its effect on vibrations of Slab Track under temperature and vehicle dynamic loads
International Journal of Non-linear Mechanics, 2014Co-Authors: Shengyang Zhu, Chengbiao CaiAbstract:Abstract This paper presents a three-dimensional finite element model to investigate the interface damage occurred between prefabricated Slab and CA (cement asphalt) mortar layer in the China Railway Track System (CRTS-II) Slab Track system. In the finite element model, a cohesive zone model with a non-linear constitutive law is introduced and utilized to model the damage, cracking and delamination at the interface. Combining with the temperature field database obtained from the three-dimensional transient heat transfer analysis, the interface damage evolution as a result of temperature change is analyzed. A three-dimensional coupled dynamic model of a vehicle and the Slab Track is then established to calculate the varying rail-supporting forces which are utilized as the inputs to the finite element model. The non-linearities of the wheel–rail contact geometry, the wheel–rail normal contact force and the wheel–rail tangential creep force are taken into account in the model. Setting the maximum interface damaged state calculated under temperature change as the initial condition, the interface damage evolution and its influence on the dynamic response of the Slab Track are investigated under the joint action of the temperature change and vehicle dynamic load. The analysis indicates that the proposed model is capable of predicting the initiation and propagation of cracks at the interface. The prefabricated Slab presents lateral warping, resulting in severe interface damage on both the sides of the Slab Track along the longitudinal direction during temperature drop process, while the interface damage level does not change significantly under vehicle dynamic loads. The interface damage has great effects on the dynamic responses of the Slab Track.