In recent years,train-tail swaying of 160 km/h electric multiple units(EMUs)inside single-line tunnels has been heavily researched,because the issue needs to be solved urgently.In this paper,a co-simulation model of v...In recent years,train-tail swaying of 160 km/h electric multiple units(EMUs)inside single-line tunnels has been heavily researched,because the issue needs to be solved urgently.In this paper,a co-simulation model of vortex-induced vibration(VIV)of the tail car body is established,and the aerodynamics of train-tail swaying is studied.The simulation results were confirmed through a field test of operating EMUs.Furthermore,the influence mechanism of train-tail swaying on the wake flow field is studied in detail through a wind-tunnel experiment and a simulation of a reduced-scaled train model.The results demonstrate that the aerodynamic force frequency(i.e.,vortex-induced frequency)of the train tail increases linearly with train speed.When the train runs at 130 km/h,with a small amplitude of train-tail swaying(within 10 mm),the vortex-induced frequency is 1.7 Hz,which primarily depends on the nose shape of the train tail.After the tail car body nose is extended,the vortex-induced frequency is decreased.As the swaying amplitude of the train tail increases(exceeding 25 mm),the separation point of the high-intensity vortex in the train wake shifts downstream to the nose tip,and the vortex-induced frequency shifts from 1.7 Hz to the nearby car body hunting(i.e.,the primary hunting)frequency of 1.3 Hz,which leads to the frequency-locking phenomenon of VIV,and the resonance intensifies train-tail swaying.For the motor vehicle of the train tail,optimization of the yaw damper to improve its primary hunting stability can effectively alleviate train-tail swaying inside single-line tunnels.Optimization of the tail car body nose shape reduces the amplitude of the vortex-induced force,thereby weakening the aerodynamic effect and solving the problem of train-tail swaying inside the single-line tunnels.展开更多
The distributed-power electric multiple units(EMUs)are widely used in high-speed railway.Due to the structural characteristic of mutual-coupled power units in EMUs,each power unit is set as an agent.Combining with the...The distributed-power electric multiple units(EMUs)are widely used in high-speed railway.Due to the structural characteristic of mutual-coupled power units in EMUs,each power unit is set as an agent.Combining with the traction/brake characteristic curve and running data of EMUs,a subtractive clustering method and pattern classification algorithm are adopted to set up a multi-model set for every agent.Then,the multi-agent model is established according to the multi-agent network topology and mutual-coupled constraint relations.Finally,we adopt a smooth start switching control strategy and a multi-agent distributed coordination control algorithm to ensure the synchronous speed tracking control of each agent.Simulation results on the actual CRH380A running data show the effectiveness of the proposed approach.展开更多
An experimental muon source(EMuS) will be built at the China Spallation Neutron Source(CSNS). In phase I of CSNS, it has been decided that EMuS will provide a proton beam of 5 kW and 1.6 GeV to generate muon beams. A ...An experimental muon source(EMuS) will be built at the China Spallation Neutron Source(CSNS). In phase I of CSNS, it has been decided that EMuS will provide a proton beam of 5 kW and 1.6 GeV to generate muon beams. A 128-channel muon spin rotation/relaxation/resonance(μSR) spectrometer is proposed as a prototype surface muon spectrometer in a sub-branch of EMuS. The prototype spectrometer includes a detection system, sample environment, and supporting mechanics. The current design has two rings located at the forward and backward directions of the muon spin with 64 detectors per ring. The simulation shows that the highest asymmetry of approximately 0.28 is achieved by utilizing two 10-mm-thick brass degraders. To obtain the optimal asymmetry, the two-ring structure is updated to a four-ring structure with 32 segments in each ring. An asymmetry of 0.42 is obtained through the simulation, which is higher than that of all the current μSR spectrometers in the world.展开更多
High speed railway technologies are rapidly development in the world.The total distance of the high speed railway is more than 40,000 kilometers in China,and many types of high speed Electrical Multi-Units(EMUs)are op...High speed railway technologies are rapidly development in the world.The total distance of the high speed railway is more than 40,000 kilometers in China,and many types of high speed Electrical Multi-Units(EMUs)are operated.The top operation velocity of the train reaches 350 km/h.New science and technologies are developing rapidly.New generation technologies such as the information technology,intelligent manufacturing,new material and processing,innovating design philosophy have revolutionary influence on the high speed train.It promotes the high speed train performance such as intelligence,reliable operation and environment-friendly.Based on many years investigation of the trend of the technology development and requirement of general public,the trend of technology development in five aspects are presented in this paper.The five aspects include economic applicability,high speed and high efficiency,green and low carbon,intelligent safety,comfortable and high quality.展开更多
The cable bracket is one of the crucial components of high-speed Electric Multiple Units(EMUs),which is fixed to the axle box by bolts to support the cable.As an important parameter of the joint surface,contact stiffn...The cable bracket is one of the crucial components of high-speed Electric Multiple Units(EMUs),which is fixed to the axle box by bolts to support the cable.As an important parameter of the joint surface,contact stiffness significantly affects the dynamic response and service life of the cable bracket.However,it is difficult to directly measure the contact stiffness of the joint surface.As a result,an identification method is proposed in this investigation to identify the contact stiffness.A finite element model incorporating both normal and tangential stiffness parameters is developed.According to the finite element model and modal testing results,an improved particle swarm optimization algorithm is employed to identify the contact stiffness of the joint surface.The effect of the contact stiffness on the vibrations of the cable bracket is investigated.The findings indicate that pre-tightening torque significantly influences the contact stiffness of the cable bracket.The contact stiffness has a great effect on the vibrations of the cable bracket.Optimal contact stiffness notably reduces vibrations of the cable bracket,thereby extending its service life.展开更多
The application of dry-type on-board traction transformers(D-OBTTs)aims to achieve lightweight electric multiple units(EMUs)and support the approach for carbon neutrality.However,the production of large capacity D-OBT...The application of dry-type on-board traction transformers(D-OBTTs)aims to achieve lightweight electric multiple units(EMUs)and support the approach for carbon neutrality.However,the production of large capacity D-OBTTs are limited due to the defects in insulation materials under the impact of short-circuit electromagnetic force.This paper is dedicated to enhancing the mechanical performance of the high-capacity D-OBTT under the influence of short-circuit electromagnetic force.It establishes and validates an electromagnetic force coupling model,while also analysing how the traditional structure leads to defects in the insulation material.To satisfy the requirements of safe and stable operation during the service life of the large capacity D-OBTT and minimise the weight,this paper proposes a comprehensive improvement of the mechanical performance under short-circuit electromagnetic force through material modification and structural optimisation.The improvement effect is verified through experiments and simulations.After comprehensive improvement,the tensile strength of the insulation material is 43%higher than the maximum principal stress on the contact surface of the insulation material,which meets the standard requirement and ensures long-term safe and stable operation of the D-OBTT during its service life.展开更多
Purpose A capture superconducting solenoid is designed for the Experimental Muon Source(EMuS)which is proposed at China Spallation Neutron Source(CSNS)in Dongguan for muon science and neutrino physics research.The cap...Purpose A capture superconducting solenoid is designed for the Experimental Muon Source(EMuS)which is proposed at China Spallation Neutron Source(CSNS)in Dongguan for muon science and neutrino physics research.The capture superconducting solenoid of the EMuS consists of four coils with different radius generating a peak central field of 5 T at 3944 A of nominal current.Methods The aluminum-stabilized NbTi Rutherford cable is used to wind the solenoid coils.Iron yokes are arranged for flux returning and field shielding.Ti alloy Ti-6Al-4V rods are adopted to support the cold mass.The vacuum vessel of the solenoid is manufactured by 304 stainless steel.The coils are pre-stressed by interference fits assembly,the outer support cylinder or binding the coils with aluminum alloy wire in order to reduce the peak stress of the coils.The parameters of the coils such as the thickness and the tensile stress of the binding wire and the thickness of the outer support cylinder have been optimized in order to minimize the cold mass by using FEA software.Results The maximum stress in the winding is allowable with two layers of 40 mm thickness outer support cylinder through interference fits assembly.But the maximum stress in the winding is allowable with 40 mm thickness of binding wire and 30 mm thickness of outer support cylinder.Conclusion The method of binding the windings with aluminum alloy wire is suggested to be used to manufacture the solenoid.This paper presents the mechanical design and analysis of the capture superconducting solenoid for EMuS.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52372403 and U2268211)the Natural Science Foundation of Sichuan Province(No.2022NSFSC0034),China+1 种基金the National Railway Group Science and Technology Program(No.2023J071)the Traction Power State Key Laboratory of the Independent Research and Development Projects(No.2022TPL-T02),China.
文摘In recent years,train-tail swaying of 160 km/h electric multiple units(EMUs)inside single-line tunnels has been heavily researched,because the issue needs to be solved urgently.In this paper,a co-simulation model of vortex-induced vibration(VIV)of the tail car body is established,and the aerodynamics of train-tail swaying is studied.The simulation results were confirmed through a field test of operating EMUs.Furthermore,the influence mechanism of train-tail swaying on the wake flow field is studied in detail through a wind-tunnel experiment and a simulation of a reduced-scaled train model.The results demonstrate that the aerodynamic force frequency(i.e.,vortex-induced frequency)of the train tail increases linearly with train speed.When the train runs at 130 km/h,with a small amplitude of train-tail swaying(within 10 mm),the vortex-induced frequency is 1.7 Hz,which primarily depends on the nose shape of the train tail.After the tail car body nose is extended,the vortex-induced frequency is decreased.As the swaying amplitude of the train tail increases(exceeding 25 mm),the separation point of the high-intensity vortex in the train wake shifts downstream to the nose tip,and the vortex-induced frequency shifts from 1.7 Hz to the nearby car body hunting(i.e.,the primary hunting)frequency of 1.3 Hz,which leads to the frequency-locking phenomenon of VIV,and the resonance intensifies train-tail swaying.For the motor vehicle of the train tail,optimization of the yaw damper to improve its primary hunting stability can effectively alleviate train-tail swaying inside single-line tunnels.Optimization of the tail car body nose shape reduces the amplitude of the vortex-induced force,thereby weakening the aerodynamic effect and solving the problem of train-tail swaying inside the single-line tunnels.
基金Supported by National Natural Science Foundation of China(61164013,U1334211,51174091)the Key Program of China Ministry of Railway(2011Z002-D)Natural Science Foundation of Jiangxi Province(20122BAB201021)
文摘The distributed-power electric multiple units(EMUs)are widely used in high-speed railway.Due to the structural characteristic of mutual-coupled power units in EMUs,each power unit is set as an agent.Combining with the traction/brake characteristic curve and running data of EMUs,a subtractive clustering method and pattern classification algorithm are adopted to set up a multi-model set for every agent.Then,the multi-agent model is established according to the multi-agent network topology and mutual-coupled constraint relations.Finally,we adopt a smooth start switching control strategy and a multi-agent distributed coordination control algorithm to ensure the synchronous speed tracking control of each agent.Simulation results on the actual CRH380A running data show the effectiveness of the proposed approach.
基金supported by the National Natural Science Foundation of China(No.11527811)the Key Program of State Key Laboratory of Particle Detection and ElectronicsA part of the work performed in the UKRI ISIS Detector Group was sponsored by the China Scholarship Council
文摘An experimental muon source(EMuS) will be built at the China Spallation Neutron Source(CSNS). In phase I of CSNS, it has been decided that EMuS will provide a proton beam of 5 kW and 1.6 GeV to generate muon beams. A 128-channel muon spin rotation/relaxation/resonance(μSR) spectrometer is proposed as a prototype surface muon spectrometer in a sub-branch of EMuS. The prototype spectrometer includes a detection system, sample environment, and supporting mechanics. The current design has two rings located at the forward and backward directions of the muon spin with 64 detectors per ring. The simulation shows that the highest asymmetry of approximately 0.28 is achieved by utilizing two 10-mm-thick brass degraders. To obtain the optimal asymmetry, the two-ring structure is updated to a four-ring structure with 32 segments in each ring. An asymmetry of 0.42 is obtained through the simulation, which is higher than that of all the current μSR spectrometers in the world.
文摘High speed railway technologies are rapidly development in the world.The total distance of the high speed railway is more than 40,000 kilometers in China,and many types of high speed Electrical Multi-Units(EMUs)are operated.The top operation velocity of the train reaches 350 km/h.New science and technologies are developing rapidly.New generation technologies such as the information technology,intelligent manufacturing,new material and processing,innovating design philosophy have revolutionary influence on the high speed train.It promotes the high speed train performance such as intelligence,reliable operation and environment-friendly.Based on many years investigation of the trend of the technology development and requirement of general public,the trend of technology development in five aspects are presented in this paper.The five aspects include economic applicability,high speed and high efficiency,green and low carbon,intelligent safety,comfortable and high quality.
基金Supported by National Natural Science Foundation of China(Grant No.U2368215)the Fundamental Research Funds for the Central Universities(Grant No.2022JBXT004)Science and Technology Planning Project of Xuzhou(Grant No.KC22293)。
文摘The cable bracket is one of the crucial components of high-speed Electric Multiple Units(EMUs),which is fixed to the axle box by bolts to support the cable.As an important parameter of the joint surface,contact stiffness significantly affects the dynamic response and service life of the cable bracket.However,it is difficult to directly measure the contact stiffness of the joint surface.As a result,an identification method is proposed in this investigation to identify the contact stiffness.A finite element model incorporating both normal and tangential stiffness parameters is developed.According to the finite element model and modal testing results,an improved particle swarm optimization algorithm is employed to identify the contact stiffness of the joint surface.The effect of the contact stiffness on the vibrations of the cable bracket is investigated.The findings indicate that pre-tightening torque significantly influences the contact stiffness of the cable bracket.The contact stiffness has a great effect on the vibrations of the cable bracket.Optimal contact stiffness notably reduces vibrations of the cable bracket,thereby extending its service life.
基金supported by National Natural Science Foundation of China(Grant/Award U1834203)Natural Science Foundation of Sichuan Province(Grants/Award 2024NSFSC0020 and 2023NSFSC0828).
文摘The application of dry-type on-board traction transformers(D-OBTTs)aims to achieve lightweight electric multiple units(EMUs)and support the approach for carbon neutrality.However,the production of large capacity D-OBTTs are limited due to the defects in insulation materials under the impact of short-circuit electromagnetic force.This paper is dedicated to enhancing the mechanical performance of the high-capacity D-OBTT under the influence of short-circuit electromagnetic force.It establishes and validates an electromagnetic force coupling model,while also analysing how the traditional structure leads to defects in the insulation material.To satisfy the requirements of safe and stable operation during the service life of the large capacity D-OBTT and minimise the weight,this paper proposes a comprehensive improvement of the mechanical performance under short-circuit electromagnetic force through material modification and structural optimisation.The improvement effect is verified through experiments and simulations.After comprehensive improvement,the tensile strength of the insulation material is 43%higher than the maximum principal stress on the contact surface of the insulation material,which meets the standard requirement and ensures long-term safe and stable operation of the D-OBTT during its service life.
基金National Natural Science Foundation of China(Project:11527811).
文摘Purpose A capture superconducting solenoid is designed for the Experimental Muon Source(EMuS)which is proposed at China Spallation Neutron Source(CSNS)in Dongguan for muon science and neutrino physics research.The capture superconducting solenoid of the EMuS consists of four coils with different radius generating a peak central field of 5 T at 3944 A of nominal current.Methods The aluminum-stabilized NbTi Rutherford cable is used to wind the solenoid coils.Iron yokes are arranged for flux returning and field shielding.Ti alloy Ti-6Al-4V rods are adopted to support the cold mass.The vacuum vessel of the solenoid is manufactured by 304 stainless steel.The coils are pre-stressed by interference fits assembly,the outer support cylinder or binding the coils with aluminum alloy wire in order to reduce the peak stress of the coils.The parameters of the coils such as the thickness and the tensile stress of the binding wire and the thickness of the outer support cylinder have been optimized in order to minimize the cold mass by using FEA software.Results The maximum stress in the winding is allowable with two layers of 40 mm thickness outer support cylinder through interference fits assembly.But the maximum stress in the winding is allowable with 40 mm thickness of binding wire and 30 mm thickness of outer support cylinder.Conclusion The method of binding the windings with aluminum alloy wire is suggested to be used to manufacture the solenoid.This paper presents the mechanical design and analysis of the capture superconducting solenoid for EMuS.
