To investigate the effect of rail pad viscoelasticity on vehicle-track-bridge coupled vibration,the fractional Voigt and Maxwell model in parallel(FVMP)was used to characterize the viscoelastic properties of the rail ...To investigate the effect of rail pad viscoelasticity on vehicle-track-bridge coupled vibration,the fractional Voigt and Maxwell model in parallel(FVMP)was used to characterize the viscoelastic properties of the rail pad based on dynamic performance test results.The FVMP model was then incorporated into the vehicle-track-bridge nonlinear coupled model,and its dynamic response was solved using a cross-iteration algorithm with a relaxation factor.Results indicate that the nonlinear coupled model achieves good convergence when the time step is less than 0.001 s,with the cross-iteration algorithm adjusting the wheel-rail force.In particular,the best convergence is achieved when the relaxation factor is within the range of 0.3-0.5.The FVMP model effectively characterizes the viscoelasticity of rail pads across a temperature range of±20℃and a frequency range of 1-1000 Hz.The viscoelasticity of rail pads significantly affects high-frequency vibrations in the coupled system,particularly around 50 Hz,corresponding to the wheel-rail coupled resonance range.Considering rail pad viscoelasticity is essential for accurately predicting track structure vibrations.展开更多
For a large-scale dynamic system,the efficiency of computation becomes a vital work sometimes in engineering practices.As a layered structural system,ballastless track and substructure occupy most part of the degrees ...For a large-scale dynamic system,the efficiency of computation becomes a vital work sometimes in engineering practices.As a layered structural system,ballastless track and substructure occupy most part of the degrees of freedom of the whole system.It is,therefore,rather important to optimize the structural models in dynamic equation formulations.In this work,a three-dimensional and coupled model for multi-rigid-body of train and finite elements of track and substructures is pre-sented by multi-scale assemble and matrix reassemble method.The matrix reassembling tactic is based on the multi-scale assemble method,through which the finite element matrix bandwidth is greatly narrowed,and the Cholesky factorization,iterative and multi-time-step solution have been introduced to efficiently obtain the train,track and substructure responses.The subgrade and its subsoil works as a typical substructural system,and comparisons with the previous model without matrix reassembling,SIMPACK and ABAQUS have been conducted to fully validate the efficiency and accuracy of this train-track-subgrade dynamic interaction model.展开更多
Within the SILVARSTAR project,a user-friendly frequency-based hybrid prediction tool has been developed to assess the environmental impact of railway-induced vibration.This tool is integrated in existing noise mapping...Within the SILVARSTAR project,a user-friendly frequency-based hybrid prediction tool has been developed to assess the environmental impact of railway-induced vibration.This tool is integrated in existing noise mapping software.Following modern vibration standards and guidelines,the vibration velocity level in a building in each frequency band is expressed as the sum of a force density(source term),line source transfer mobility(propagation term)and building correction factor(receiver term).A hybrid approach is used that allows for a combination of experimental data and numerical predictions,providing increased flexibility and applicability.The train and track properties can be selected from a database or entered as numerical values.The user can select soil impedance and transfer functions from a database,pre-computed for a wide range of parameters with state-of-the-art models.An experimental database of force densities,transfer functions,free field vibration and input parameters is also provided.The building response is estimated by means of building correction factors.Assumptions within the modelling approach are made to reduce computation time but these can influence prediction accuracy;this is quantified for the case of a nominal intercity train running at different speeds on a ballasted track supported by homogeneous soil of varying stiffness.The paper focuses on the influence of these parameters on the compliance of the track–soil system and the free field response.We also demonstrate the use and discuss the validation of the vibration prediction tool for the case of a high-speed train running on a ballasted track in Lincent(Belgium).展开更多
基金Project(2023ZDZX0008)supported by the Sichuan Major Science and Technology Project,ChinaProject(52308468)supported by the National Natural Science Foundation of ChinaProject(2022JBQY009)supported by the Fundamental Research Funds for the Central Universities(Science and Technology Leading Talent Team Project),China。
文摘To investigate the effect of rail pad viscoelasticity on vehicle-track-bridge coupled vibration,the fractional Voigt and Maxwell model in parallel(FVMP)was used to characterize the viscoelastic properties of the rail pad based on dynamic performance test results.The FVMP model was then incorporated into the vehicle-track-bridge nonlinear coupled model,and its dynamic response was solved using a cross-iteration algorithm with a relaxation factor.Results indicate that the nonlinear coupled model achieves good convergence when the time step is less than 0.001 s,with the cross-iteration algorithm adjusting the wheel-rail force.In particular,the best convergence is achieved when the relaxation factor is within the range of 0.3-0.5.The FVMP model effectively characterizes the viscoelasticity of rail pads across a temperature range of±20℃and a frequency range of 1-1000 Hz.The viscoelasticity of rail pads significantly affects high-frequency vibrations in the coupled system,particularly around 50 Hz,corresponding to the wheel-rail coupled resonance range.Considering rail pad viscoelasticity is essential for accurately predicting track structure vibrations.
基金supported by the National Natural Science Foundation of China(Grant Nos.52378468)Science and Technology Research and Development Program Project of China railway group limited(Major Special Project,No.2022-Major-14,2021-Special-08,2021-Major-02)+3 种基金Young Elite Scientists Sponsorship Program by CAST(2020-2022QNRC002)Central South University Innovation-Driven Research Programme(2023CXQD073)the National Natural Science Foundation of Hunan Province(Grant Nos.2022JJ20071 and 2021JJ30850)National Key R&D Program‘Transportation Infrastructure’‘Reveal the list and take command’project(2022YFB2603301).
文摘For a large-scale dynamic system,the efficiency of computation becomes a vital work sometimes in engineering practices.As a layered structural system,ballastless track and substructure occupy most part of the degrees of freedom of the whole system.It is,therefore,rather important to optimize the structural models in dynamic equation formulations.In this work,a three-dimensional and coupled model for multi-rigid-body of train and finite elements of track and substructures is pre-sented by multi-scale assemble and matrix reassemble method.The matrix reassembling tactic is based on the multi-scale assemble method,through which the finite element matrix bandwidth is greatly narrowed,and the Cholesky factorization,iterative and multi-time-step solution have been introduced to efficiently obtain the train,track and substructure responses.The subgrade and its subsoil works as a typical substructural system,and comparisons with the previous model without matrix reassembling,SIMPACK and ABAQUS have been conducted to fully validate the efficiency and accuracy of this train-track-subgrade dynamic interaction model.
基金the project SILVARSTAR funded from the Shift2Rail Joint Undertaking under the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement 101015442。
文摘Within the SILVARSTAR project,a user-friendly frequency-based hybrid prediction tool has been developed to assess the environmental impact of railway-induced vibration.This tool is integrated in existing noise mapping software.Following modern vibration standards and guidelines,the vibration velocity level in a building in each frequency band is expressed as the sum of a force density(source term),line source transfer mobility(propagation term)and building correction factor(receiver term).A hybrid approach is used that allows for a combination of experimental data and numerical predictions,providing increased flexibility and applicability.The train and track properties can be selected from a database or entered as numerical values.The user can select soil impedance and transfer functions from a database,pre-computed for a wide range of parameters with state-of-the-art models.An experimental database of force densities,transfer functions,free field vibration and input parameters is also provided.The building response is estimated by means of building correction factors.Assumptions within the modelling approach are made to reduce computation time but these can influence prediction accuracy;this is quantified for the case of a nominal intercity train running at different speeds on a ballasted track supported by homogeneous soil of varying stiffness.The paper focuses on the influence of these parameters on the compliance of the track–soil system and the free field response.We also demonstrate the use and discuss the validation of the vibration prediction tool for the case of a high-speed train running on a ballasted track in Lincent(Belgium).
