Determining future high speed rail review topics through bibliometric analysis

As High Speed Rail(HSR)has proliferated globally,so has a related research field dedicated to exploring and addressing its unique issues.Yet,studies to understand and classify the HSR research domain are limited.This paper addresses the gap,using bibliometric analysis to identify future research areas and 20 candidate topics for literature review based on keyword analysis through VOSviewer.Article and review papers related to HSR published in the last 20 years(2003-2022)were retrieved from Scopus,and then analyzed to determine the split in knowledge between languages,the collaboration between countries and institutions,highly productive and cited journals,and research topics which have and have not been reviewed.Approximately 30%of the search results were published exclusively in Chinese,highlighting the importance of extending the evaluation to cover both languages.This is a novel aspect of the work,which has enabled the recognition of potential knowledge gaps.It is recommended that future reviews incorporate works in both languages,possibly through international collaboration.Institutions in China and other countries that are strong collaborators have been identified,as well as relevant,highly cited journals.

Corrosion Test of the Steel Plate in a WJ-8 Fastener for High Speed Rail

It was found that the steel plate in the composite plate in the WJ-8 fastener used in high speed rail is rusty. The objective of this study is to test the zinc coating of the steel plate. A literature review was conducted to identify the zinc coating techniques, and the companies that can provide different coating service was identified. A salt fog chamber was built that was in compliance with the ANSI B117 code, and the steel plates that were coated by the identified companies were tested using the salt fog chamber. The results indicated that the coating technique that had the best performance in preventing corrosion was the Greenkote plates with passivation. The galvanized option had the roughest coating layer, and it was the most reactive in the salt water solution. This makes it non-ideal for the dynamic rail environment because the increased friction of the plate could damage the supports, especially during extreme temperatures that would cause the rail to expand or contract. Greenkote with Phosphate and ArmorGalv also provided increased corrosion prevention with a smooth, strong finish, but it had more rust on the surface area than the Greenkote with ELU passivation. The ArmorGalv sample had more rust on the surface area than the Greenkote samples. This may not be a weakness in the ArmorGalv process;rather, it likely was the result of this particular sample not having the added protection of a colored coating.

Adaptive Fault Estimation for Dynamics of High Speed Train Based on Robust UKF Algorithm

This paper proposes an adaptive unscented Kalman filter algorithm(ARUKF)to implement fault estimation for the dynamics of high⁃speed train(HST)with measurement uncertainty and time⁃varying noise with unknown statistics.Firstly,regarding the actuator and sensor fault as the auxiliary variables of the dynamics of HST,an augmented system is established,and the fault estimation problem for dynamics of HST is formulated as the state estimation of the augmented system.Then,considering the measurement uncertainties,a robust lower bound is proposed to modify the update of the UKF to decrease the influence of measurement uncertainty on the filtering accuracy.Further,considering the unknown time⁃varying noise of the dynamics of HST,an adaptive UKF algorithm based on moving window is proposed to estimate the time⁃varying noise so that accurate concurrent actuator and sensor fault estimations of dynamics of HST is implemented.Finally,a five-car model of HST is given to show the effectiveness of this method.

Study on the technologies development trend of high speed EMUs

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.

Behaviour of non-ballast pre-stressed and precast track structures in high speed railway based on multiscale finite element model

In order to make further study on the mechanical property of CRTSIII type slab non-ballast track structures,which was self-designed in China,based on the method of the multiscale finite element model(FEM),the traditional FEM of slab non-ballast track structures was improved.The multiscale FEM of CRTSII type slab nonballast track structures was established based on the general finite element program ABAQUs.Then the comparative calculation was made between various FEMs,showing that the high solution precision,fast modelling speed and high solution efficiency could be obtained.Therefore,the multiscale FEM was suitable for the parametric study on mechanical behaviour of CRTSII type slab non-ballast track structures,and then the key influence factor and constructions could be optimized.

Current situation and development trend of design methods for subgrade structure of high speed railways

Purpose–This method will become a new development trend in subgrade structure design for high speed railways.Design/methodology/approach–This paper summarizes the structural types and design methods of subgrade bed for high speed railways in China,Japan,France,Germany,the United States and other countries based on the study and analysis of existing literature and combined with the research results and practices of high speed railway subgrade engineering at home and abroad.Findings–It is found that in foreign countries,the layered reinforced structure is generally adopted for the subgrade bed of high speed railways,and the unified double-layer or multi-layer structure is adopted for the surface layer of subgrade bed,while the simple structure is adopted in China;in foreign countries,different inspection parameters are adopted to evaluate the compaction state of fillers according to their respective understanding and practice,while in China,compaction coefficient,subsoil coefficient and dynamic deformation modulus are adopted for such evaluation;in foreign countries,the subgrade top deformation control method,the subgrade bottom deformation control method,the subsurface fill strength control method are mainly adopted in subgrade bed structure design of high speed railways,while in China,dynamic deformation control of subgrade surface and dynamic strain control of subgrade bed bottom layer is adopted in the design.However,the cumulative deformation of subgrade caused by train cyclic vibration load is not considered in the existing design methods.Originality/value–This paper introduces a new subgrade structure design method based on whole-process dynamics analysis that meets subgrade functional requirements and is established on the basis of the existing research at home and abroad on prediction methods for cumulative deformation of subgrade soil.

Study on dynamic response of high speed train window glass under tunnel aerodynamic effects

Purpose-This paper aims to analyze the bearing characteristics of the high speed train window glass under aerodynamic load effects.Design/methodology/approach-In order to obtain the dynamic strain response of passenger compartment window glass during high-speed train crossing the tunnel,taking the passenger compartment window glass of the CRH3 high speed train onWuhan-Guangzhou High Speed Railway as the research object,this study tests the strain dynamic response and maximum principal stress of the high speed train passing through the tunnel entrance and exit,the tunnel and tunnel groups as well as trains meeting in the tunnel at an average speed of 300 km$h-1.Findings-The results show that while crossing the tunnel,the passenger compartment window glass of high speed train is subjected to the alternating action of positive and negative air pressures,which shows the typical mechanic characteristics of the alternating fatigue stress of positive-negative transient strain.The maximum principal stress of passenger compartment window glass for high speed train caused by tunnel aerodynamic effects does not exceed 5 MPa,and the maximum value occurs at the corresponding time of crossing the tunnel groups.The high speed train window glass bears medium and low strain rates under the action of tunnel aerodynamic effects,while the maximum strain rate occurs at the meeting moment when the window glass meets the train head approaching from the opposite side in the tunnel.The shear modulus of laminated glass PVB film that makes up high speed train window glass is sensitive to the temperature and action time.The dynamically equivalent thickness and stiffness of the laminated glass and the dynamic bearing capacity of the window glass decrease with the increase of the action time under tunnel aerodynamic pressure.Thus,the influence of the loading action time and fatigue under tunnel aerodynamic effects on the glass strength should be considered in the design for the bearing performance of high speed train window glass.Originality/value-The research results provide data support for the analysis of mechanical characteristics,damage mechanism,strength design and structural optimization of high speed train glass.

Development of rail technology for high speed railway in China

Purpose–The purpose of this paper is to summarize the status and characteristics of rail technology of high-speed railway in China,and point out the development direction of rail technology of high-speed railway.Design/methodology/approach–This study reviews the evolution of high-speed rail standards in China,comparing their chemical composition,mechanical attributes and geometric specifications with EN standards.It delves into the status of rail production technology,shifts in key performance indicators and the quality characteristics of rails.The analysis further examines the interplay between wheels and rails,the implementation of grinding technology and the techniques for inspecting rail service conditions.It encapsulates the salient features of rail operation and maintenance within the high-speed railway ecosystem.The paper concludes with an insightful prognosis of high-speed railway technology development in China.Findings–The rail standards of high-speed railway in China are scientific and advanced,highly operational and in line with international standards.The quality and performance of rail in China have reached the world’s advanced level.The 60N profile guarantees the operation quality of wheel–rail interaction effectively.The rail grinding technology system scientifically guarantees the long-term good service performance of the rail.The rail service state detection technology is scientific and efficient.The rail technology will take“more intelligent”and“higher speed”as the development direction to meet the future needs of high-speed railway in China.Originality/value–The development direction of rail technology for high-speed railway in China is defined,which will promote the continuous innovation and breakthrough of rail technology.

Medium-term forecast of daily passenger volume of high speed railway based on DLP-WNNMedium-term forecast of dailypassenger volume of high speedrailway based on DLP-WNN

Purpose – This paper aims to propose a medium-term forecast model for the daily passenger volume of HighSpeed Railway (HSR) systems to predict the daily the Origin-Destination (OD) daily volume formultiple consecutivedays (e.g. 120 days).Design/methodology/approach – By analyzing the characteristics of the historical data on daily passengervolume of HSR systems, the date and holiday labels were designed with determined value ranges.In accordance to the autoregressive characteristics of the daily passenger volume of HSR, the Double LayerParallel Wavelet Neural Network (DLP-WNN) model suitable for the medium-term (about 120 d) forecast of thedaily passenger volume of HSR was established. The DLP-WNN model obtains the daily forecast result byweighed summation of the daily output values of the two subnets. Subnet 1 reflects the overall trend of dailypassenger volumes in the recent period, and subnet 2 the daily fluctuation of the daily passenger volume toensure the accuracy of medium-term forecast.Findings – According to the example application, in which the DLP-WNN modelwas used for the medium-termforecast of the daily passenger volumes for 120 days for typical O-D pairs at 4 different distances, the averageabsolute percentage error is 7%-12%, obviously lower than the results measured by the Back Propagation (BP)neural network, the ELM (extreme learning machine), the ELMAN neural network, the GRNN (generalizedregression neural network) and the VMD-GA-BP. The DLP-WNN model was verified to be suitable for themedium-term forecast of the daily passenger volume of HSR.Originality/value – This study proposed a Double Layer Parallel structure forecast model for medium-termdaily passenger volume (about 120 days) of HSR systems by using the date and holiday labels and WaveletNeural Network. The predict results are important input data for supporting the line planning, scheduling andother decisions in operation and management in HSR systems.

Design Innovation and Practice of“One Stationwith One Landscape”for High Speed Railway Stations

Since the founding of New China,railway station design has experienced a long development and evolution process,and has now developed to the fourth generation,which is called the New Era Railway Station.Guided by the new concept of building up a“well-connected fully-integrated,envionmeni-friendly passenger-oriented,economic-efficient,culturally-rich,intelligent and convenient”station,the station building becomes more personalized and specialized displaying distinctive effects,and the design connotation of“one station with one landscape”has also been widened and deepened From the simple differentiated design of facade image,the design is gradually becoming station-specific and customized with station-city integrated development and passengers'boarding and alighting feelings as the core.The purpose is to make the station truly become a prominent card and landmark building that facilitates city development.

Dynamic Performance of High Speed Solenoid Valve with Parallel Coils

The methods of improving the dynamic performance of high speed on/off solenoid valve include increasing the magnetic force of armature and the slew rate of coil current, decreasing the mass and stroke of moving parts. The increase of magnetic force usually leads to the decrease of current slew rate, which could increase the delay time of the dynamic response of solenoid valve. Using a high voltage to drive coil can solve this contradiction, but a high driving voltage can also lead to more cost and a decrease of safety and reliability. In this paper, a new scheme of parallel coils is investigated, in which the single coil of solenoid is replaced by parallel coils with same ampere turns. Based on the mathematic model of high speed solenoid valve, the theoretical formula for the delay time of solenoid valve is deduced. Both the theoretical analysis and the dynamic simulation show that the effect of dividing a single coil into N parallel sub-coils is close to that of driving the single coil with N times of the original driving voltage as far as the delay time of solenoid valve is concerned. A specific test bench is designed to measure the dynamic performance of high speed on/off solenoid valve. The experimental results also prove that both the delay time and switching time of the solenoid valves can be decreased greatly by adopting the parallel coil scheme. This research presents a simple and practical method to improve the dynamic performance of high speed on/off solenoid valve.

Influence of Cerium on Solidification Microstructure of M2 High Speed Steel

The influence of Ce on the solidification microstructures of M2 high speed steel was studied. The results show that Ce has the effect of alleviating the segregation of alloying elements such as W and Mo in high speed steel. With the addition of Ce, the amount of eutectic carbides is decreased and the flakes of the carbides are refined. Ce mainly segregates onto the interface between the eutectic carbide and austenite, and a Dart of Ce enters M2C carbide. Ce can also enhance the breaking and spheroidizing of the network eutectic carbides during high temperature heat treatment.

A study on centrifugal casting of high speed steel roll

High speed steel (HSS) rolls can replace traditional rolls such as alloyed cast iron rolls and powder metallurgical (PM) hard alloy rolls. The main reasons for the replacement are that the wear resistance of low-cost alloyed cast iron rolls is poor and the cost of high-quality PM hard alloy rolls is very high. By means of centrifugal casting, HSS rolls having excellent wear resistance have been manufactured. The hardness of the HSS roll is 6.5~67 HRC, the range of variation is smaller than 2 HRC and its impact toughness is 15 J/cm2. The wear rate of HSS rolls used in the pre-finishing stands of high-speed hot wire-rod rolling mill reaches 2.5×10-4mm per ton steel. Furthermore, the manufacturing cost of HSS rolls is significantly lower than that of PM hard alloy rolls; it is only 30 percent of that of PM hard alloy rolls.

Numerical simulation and control of welding distortion for double floor structure of high speed train

The welding heat source models and the plastic tension zone sizes of a typical weld joint involved in the double floor structure of high speed train under different welding parameters were calculated by a thermal-elastic-plastic FEM analysis based on SYSWELD code.Then,the welding distortion of floor structure was predicted using a linear elastic FEM and shrinkage method based on Weld Planner software.The effects of welding sequence,clamping configuration and reverse deformation on welding distortion of floor structure were examined numerically.The results indicate that the established elastic FEM model for floor structure is reliable for predicting the distribution of welding distortion in view of the good agreement between the calculated results and the measured distortion for real double floor structure.Compared with the welding sequence,the clamping configuration and the reverse deformation have a significant influence on the welding distortion of floor structure.In the case of30 mm reverse deformation,the maximum deformation can be reduced about 70%in comparison to an actual welding process.

STUDY ON CRYOGENIC PHASE CHANGE & WEAR CHARACTERISTIC OF HIGH SPEED STEEL

The microscopic structure change rule in high speed steel (HSS) after an additional cryogenic treatment was studied in this paper. Highly dispersed nano-carbide (η-Fe2 C) separated from tempering martensite was found distributed on twin planes of marten-site and dislocation places. Retained austenite was found sheared into martensite and nano-carbide separated at the same time. In addition, the tempering martensite was fine-grained. The stated changes of HSS evidently improve the lifespan of HSS cutter and fully show the advantages of nano-structure. The cryogenic treatment of HSS also improves the roughness of HSS cutter (decrease Ra number by about 50%) and greatly increases the wear resistance of HSS cutter. Further experiments on the wear characteristic of HSS cutter supported the findings mentioned above. The stated HSS treatment technology would implement nano-structure of traditional tool steel through phase change. It could be a new method to improve the performance of HSS cutter.

MICROSTRUCTURAL CHARACTERISTICS AND MECHANICAL PROPERTIES OF SPRAY FORMED HIGH SPEED STEEL FOR WORK ROLL

The mechanical properties and microstructure characteristics of a high speed steel (HSS) for roll has been studied. As compared with the as-cast HSS, the spray-formed HSS have fine grain and segregation free microstructures. Carbides distribute uniformly. The morphology and types of the carbides in spray-formed HSS are different from those in as-cast HSS. The results of the high temperature tensile experiment show that, as to spray-formed HSS, there is a possibility of superplastic deformation in the range of 780-810℃.

Effects of current waveform parameters during droplet transfer on spatter in high speed waveform controlled Short-circuiting GMAW

Aim at improving the stability of the Short-circuiting Gas Metal Arc Welding （GMAW-S） process for the enhanced speed usage, effects of current waveform parameters during short-term on the welding stability have been investigated by experimental method. The welding power source used for the research is an inverter with a special current waveform control. It is shown that the spatter decreases at first then increases with each increase of the low current period, current increase rate and the maximum current limit. The test results are provided for welding of 1 mm and 3 mm mild steel at speed of 1.2 m/min. The stable GMA W-S process under high speed welding condition has been achieved by optimizing the parameters.

Effect of RE-Al-N on Structures and Properties of M2 Cast High Speed Steel

M2 cast high speed steel was inoculated by addition of rare earth(RE)-Al-N, network eutectic carbides were eliminated, matrix microstructures were refined and the segregation of tungsten and molybdenum elements was relieved. In the condition that the hardness does not decrease, impact toughness obviously increases. Quenching at 1180 ℃ and three-times tempering at 560 ℃, the hardness of M2 cast high speed steel is 65～66 HRC, and impact toughness reaches 21.3 (J·cm^(-2)). Modified M2 cast high speed steel has excellent thermal fatigue resistance and high temperature wear resistance. Roller made in modified M2 cast high speed steel has excellent service effect when it is used in slit rolling mill of hot rolling bar mill.

HIGH SPEED MILLING OF GRAPHITE ELECTRODE WITH ENDMILL OF SMALL DIAMETER

Graphite becomes the prevailing electrode material in electrical discharging machining （EDM）currently.Orthogonal cutting experiments are carried out to study the characteristics of graphite chip formation process.High speed milling experiments are conducted to study tool wear and cutting forces.The results show that depth of cut has great influence on graphite chip formation.The removal process of graphite in high speed milling is the mutual result of cutting and grinding process. Graphite is prone to cause severe abrasion wear to coated carbide endmills due to its high abrasiveness nature.The major patterns of tool wear are flank wear,rake wear,micro-chipping and breakage. Cutting forces can be reduced by adoption of higher cutting speed,moderate feed per tooth,smaller radial and axial depths of cut,and up cutting.

Study on stable and meta-stable carbides in a high speed steel for rollers during tempering processes

A high speed steel （HSS） was studied for rollers in this work. The steel was quenched at 1150℃ and tempered at 520℃. The phase structures of the steel were determined by X-ray diffraction （XRD）, and the hardness of specimens was measured. The volume fraction of carbides was counted by Image-Pro Plus software. The typical microstructures were observed by field emission scanning electron microscope （FESEM）. Stable and meta-stable carbides were deduced by removing the existing phases one by one in the Fe-C equilibrium calculation. It is found that the precipitated carbides are bulk-like MC, long stripe-like M2C, fishbone-like M6C, and daisy-like M7C3 during the tempering process. The stable carbides are MC and M6C, but the meta-stable ones are M2C, M7C3, and M3C.