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Sakdirat Kaewunruen - One of the best experts on this subject based on the ideXlab platform.
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Parametric Studies Into Creep and Shrinkage Characteristics in Railway Prestressed Concrete Sleepers
Frontiers in Built Environment, 2020Co-Authors: Sakdirat Kaewunruen, Peter Robery, Alexander RemennikovAbstract:Prestressed Concrete is very suitable for railway Sleepers because of its many superior advantages in high performance, maintenance, sustainability, and construction. Prestressed Concrete improved the structural performance which has stronger tensile resistance in comparison with common Concrete. However, the long-term performance largely depends on creep and shrinkage responses. The effects of time-dependent phenomena on prestressed Concrete Sleeper are investigated. In the past, many investigators have proposed various material models to predict creep and shrinkage but those were mostly based on general reinforced Concrete concept. The popular uses of prestressed Concrete have led to a concern of practitioners whether those existing predictive models could be realistically applied to prestressed Concrete. Due to high initial elastic shortening in prestressed Concrete, the creep and shrinkage effects should be critically re-evaluated in flexural members. This study investigates and compares the effects of creep and shrinkage on railway prestressed Concrete Sleepers. The comparison between prediction models underpinned by European Standard Eurocode 2, American Standard ACI, and Australian Standard AS3600-2009 provides the new insight into the time-dependent performance of Concrete Sleepers installed in various locations. The outcome of this study will help rail track engineers to better design and maintain railway infrastructure, improving asset management efficacy.
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Evaluation of remaining fatigue life of Concrete Sleeper based on field loading conditions
Engineering Failure Analysis, 2019Co-Authors: Ruilin You, Sakdirat KaewunruenAbstract:Abstract The main functions of the Sleepers in ballasted tracks include transferring loads, securing rail gauge and maintaining railway track geometry. Sleepers can be manufactured using timber, Concrete, steel or other engineered materials, but Concrete is most commonly used around the world. There are a number of researches on the impact load characteristics and the ultimate load carrying capacity of prestressed Concrete Sleepers, but research on the fatigue life of prestressed Concrete Sleepers is very limited. A prestressed Concrete Sleeper's fatigue damage is mainly due to the repeated loads derived from dynamic wheel-rail interactions, especially when either wheel or rail irregularity is present. Fatigue failure is thus a time-dependent limited state where a Concrete Sleeper accumulates damage to a failure point over its service life. Concrete Sleepers could usually suffer from the dynamic fatigue loading spectra throughout their whole lives, and simultaneously, both static and dynamic load-carrying capacities of Concrete Sleepers degrades over time. Therefore, a fatigue life assessment is an important and complicated research frontier. Field loading conditions, material time-dependent and dynamic properties, and the dynamic bending moments of prestressed Concrete Sleepers are quantitatively analysed in this study. This paper also presents an updated fatigue life assessment method for Concrete Sleepers, and provides a case study based on actual field loading conditions and the time-dependent behaviour of materials. The new insights obtained from this study will improve Concrete Sleeper maintenance and inspection criteria, and provide a new reference for a rational dynamic design principle of railway Concrete Sleepers and bearers.
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Attenuation Effect of Material Damping on Impact Vibration Responses of Railway Concrete Sleepers
Sustainable Solutions for Railways and Transportation Engineering, 2018Co-Authors: Sakdirat Kaewunruen, Ange-therese Akono, Alexander RemennikovAbstract:In railway industry, high strength Concrete has been adopted for track slabs and railway Sleepers for more than half a century. Prestressed Concrete Sleepers (or railroad ties) are designed usually using high strength Concrete (>55 MPa) in order to carry and transfer the wheel loads from the rails to the ground and to maintain rail gauge for safe train travels. In general, the railway Sleepers are installed as the crosstie beam support in ballasted railway tracks. Statistically, they are subjected to impact loading conditions induced by train operations over wheel or rail irregularities, such as flat wheels, dipped rails, crossing transfers, rail squats, corrugation, etc. These defects can be commonly found during the operational stage of life cycle. The magnitude of the shock load depends on various factors such as axle load, types of wheel/rail imperfections, speeds of vehicle, track stiffness, etc. This paper demonstrates the investigations into the dynamic responses of in-situ prestressed Concrete Sleepers using high strength materials, particularly under a variety of impact loads. The nonlinear finite element model of full-scale prestressed Concrete Sleeper with the realistic support condition has been developed using a finite element package, STRAND7. It has been verified by the experiments carried out using the high capacity drop-weight impact machine and experimental modal testing. The experimental results exhibited very good correlation with numerical simulations. In this paper, the numerical studies are extended to evaluate the dynamic behaviors of high strength Concrete Sleepers modified by crumb rubbers to increase material damping coefficients. The outcome of this study can potentially lead to the utilization and practical design guideline of high strength Concrete engineered by crumb rubber from wasted tires and plastics for prestressed Concrete Sleepers.
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Nonlinear finite element analysis for structural capacity of railway prestressed Concrete Sleepers with rail seat abrasion
Engineering Failure Analysis, 2018Co-Authors: Ruilin You, Keiichi Goto, Chayut Ngamkhanong, Sakdirat KaewunruenAbstract:Abstract Prestressed Concrete Sleepers are the most commonly used type of railway Sleepers in ballasted railway track. They have a strong influence on track performance, track stiffness and railway safety. Reportedly in many railway lines (especially in heavy-rail networks), many prestressed Concrete Sleepers have failed due to rail seat abrasion (RSA). RSA is a wear deterioration of the Concrete underneath the rail that results in various problems such as loss of fastening toe load, gauge variation, improper rail cant, and eventually loss of rail fastening. In addition, the RSA will directly decrease the capacity of worn Concrete Sleepers. However, to the best of authors' knowledge, there were very few studies that quantitatively examined the effects of RSA on the structural capacity of the prestressed Concrete Sleepers. In this paper, a numerical study is executed to evaluate the load-carrying capacity of a prestressed Concrete Sleeper using LS-DYNA. The nonlinear model was validated firstly based on both theoretical analyses and experimental results in accordance with Australian Standard. Using the validated finite element model, the influences of different wear depth of RSA are investigated; and different compression strength and tensile strength of Concrete and the prestress losses are highlighted. The outcomes of this study lead to better insight into the influences of RSA more clearly and improve track maintenance and inspection criteria.
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Effects of vertical and through holes on cyclic behaviour of railway Concrete Sleepers
Road and Rail Infrastructure V, 2018Co-Authors: Ruilin You, Sakdirat KaewunruenAbstract:Railway Sleeper is the very important element in rail track structure. Nowadays, prestressed Concrete is the most common type used in railway Sleeper because of its good structural performance. The main duties of Sleeper are to distribute the wheel load to the formation and keep the rail gauge. Most of current design codes for Sleepers design techniques rely on allowable stresses and material strength. However, railway Sleepers also experience high frequent cyclic load due to wheel-rail interaction. The cracking could occur in prestressed Concrete Sleepers due to cyclic behaviour and accumulation of fatigue could finally result in prestressed Concrete Sleepers’ failure. In addition, the Concrete Sleepers are often modified on construction sites to fit in other systems such as cables, signalling gears, drainage pipes, etc. This paper presents the results of the extensive theoretical and analytical investigation aimed at predicted cyclic behaviour on prestressed Concrete Sleepers with holes. It highlights the effects on cyclic behaviours of railway Concrete Sleepers. The insight of this paper can be used to evaluate the service performance and predict the cyclic behaviours of the Concrete Sleeper, as well providing design flexibility and broadening the design principle. The outcome of this study may also improve the rail track maintenance and inspection criteria, in order to establish an appropriate track condition monitoring network in practice.
Alexander Remennikov - One of the best experts on this subject based on the ideXlab platform.
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Parametric Studies Into Creep and Shrinkage Characteristics in Railway Prestressed Concrete Sleepers
Frontiers in Built Environment, 2020Co-Authors: Sakdirat Kaewunruen, Peter Robery, Alexander RemennikovAbstract:Prestressed Concrete is very suitable for railway Sleepers because of its many superior advantages in high performance, maintenance, sustainability, and construction. Prestressed Concrete improved the structural performance which has stronger tensile resistance in comparison with common Concrete. However, the long-term performance largely depends on creep and shrinkage responses. The effects of time-dependent phenomena on prestressed Concrete Sleeper are investigated. In the past, many investigators have proposed various material models to predict creep and shrinkage but those were mostly based on general reinforced Concrete concept. The popular uses of prestressed Concrete have led to a concern of practitioners whether those existing predictive models could be realistically applied to prestressed Concrete. Due to high initial elastic shortening in prestressed Concrete, the creep and shrinkage effects should be critically re-evaluated in flexural members. This study investigates and compares the effects of creep and shrinkage on railway prestressed Concrete Sleepers. The comparison between prediction models underpinned by European Standard Eurocode 2, American Standard ACI, and Australian Standard AS3600-2009 provides the new insight into the time-dependent performance of Concrete Sleepers installed in various locations. The outcome of this study will help rail track engineers to better design and maintain railway infrastructure, improving asset management efficacy.
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Attenuation Effect of Material Damping on Impact Vibration Responses of Railway Concrete Sleepers
Sustainable Solutions for Railways and Transportation Engineering, 2018Co-Authors: Sakdirat Kaewunruen, Ange-therese Akono, Alexander RemennikovAbstract:In railway industry, high strength Concrete has been adopted for track slabs and railway Sleepers for more than half a century. Prestressed Concrete Sleepers (or railroad ties) are designed usually using high strength Concrete (>55 MPa) in order to carry and transfer the wheel loads from the rails to the ground and to maintain rail gauge for safe train travels. In general, the railway Sleepers are installed as the crosstie beam support in ballasted railway tracks. Statistically, they are subjected to impact loading conditions induced by train operations over wheel or rail irregularities, such as flat wheels, dipped rails, crossing transfers, rail squats, corrugation, etc. These defects can be commonly found during the operational stage of life cycle. The magnitude of the shock load depends on various factors such as axle load, types of wheel/rail imperfections, speeds of vehicle, track stiffness, etc. This paper demonstrates the investigations into the dynamic responses of in-situ prestressed Concrete Sleepers using high strength materials, particularly under a variety of impact loads. The nonlinear finite element model of full-scale prestressed Concrete Sleeper with the realistic support condition has been developed using a finite element package, STRAND7. It has been verified by the experiments carried out using the high capacity drop-weight impact machine and experimental modal testing. The experimental results exhibited very good correlation with numerical simulations. In this paper, the numerical studies are extended to evaluate the dynamic behaviors of high strength Concrete Sleepers modified by crumb rubbers to increase material damping coefficients. The outcome of this study can potentially lead to the utilization and practical design guideline of high strength Concrete engineered by crumb rubber from wasted tires and plastics for prestressed Concrete Sleepers.
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Static and dynamic behaviours of railway prestressed Concrete Sleepers with longitudinal through hole
IOP Conference Series: Materials Science and Engineering, 2017Co-Authors: Chayut Ngamkhanong, Sakdirat Kaewunruen, Alexander RemennikovAbstract:As the crosstie beam in railway track systems, the prestressed Concrete Sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed Concrete has played a significant role as to maintain the high endurance of the Sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed Concrete Sleepers in railway tracks, there have always been many demands from rail engineers to improve serviceability and functionality of Concrete Sleepers. For example, signalling, fibre optic, equipment cables are often damaged either by ballast corners or by tamping machine. There has been a need to re-design Concrete Sleeper to cater cables internally so that they would not experience detrimental or harsh environments. Accordingly, this study will investigate the effects of through hole or longitudinal hole on static and dynamic behaviours of Concrete Sleepers under rail shock loading. The modified compression field theory for ultimate strength design of Concrete Sleepers will be highlighted in this study. The outcome of this study will enable the new design and calculation methods for prestressed Concrete Sleepers with holes and web opening that practically benefits civil, track and structural engineers in railway industry.
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on Flexural Behaviour of Railway Concrete Sleeper under Severe
2016Co-Authors: Sakdirat Kaewunruen, Alexander Remennikov, S. Kaewunruen, Alex M. RemennikovAbstract:Interactions between the wheel of rolling stocks and the rail often generate interfacial impact forces to railway tracks. The dynamic impact loads are of very high magnitude but short duration, and are caused by either wheel or rail abnormalities such as flat wheels, dipped rails, etc. Although the possibility of the large impact loading to cause an extreme failure to an in-situ Concrete Sleeper could be very low about once or twice in the design life cycle, the damage of track components especially for the Concrete Sleepers is often observed. The railway Sleeper is a major component of railway tracks. Its role is to distribute the load from the rails to the underlying ballast bed. Up to current knowledge, the behaviour of the in-situ prestressed Concrete Sleepers under the impact loading has not yet been thoroughl
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Structural Behaviours of Railway Prestressed Concrete Sleepers (Crossties) With Hole and Web Openings
Procedia Engineering, 2016Co-Authors: Sakdirat Kaewunruen, Erosha Kahawatta Gamage, Alexander RemennikovAbstract:Abstract As the crosstie beam in railway track systems, the prestressed Concrete Sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed Concrete has played a significant role as to maintain the high endurance of the Sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed Concrete Sleepers in railway tracks, there have always been considerable demands from rail and track engineers to improve serviceability and functionality of Concrete Sleepers. For example, signalling, fibre optic, equipment cables are often damaged either by acute ballast corners or by tamping machine operation. There has been a significant need to re-design Concrete Sleeper to cater cables internally so that they would not experience detrimental or harsh environments. Accordingly, this study is the world first to experimentally investigate the effects of holes and web openings on structural behaviours of Concrete Sleepers under rail loading condition. The modified compression field theory for ultimate strength behaviours of Concrete Sleepers will be highlighted in this study. The outcome of this study will enable the new design and calculation methods for prestressed Concrete Sleepers with holes and web opening that practically benefits civil, track and structural engineers in railway industry.
Alex M. Remennikov - One of the best experts on this subject based on the ideXlab platform.
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on Flexural Behaviour of Railway Concrete Sleeper under Severe
2016Co-Authors: Sakdirat Kaewunruen, Alexander Remennikov, S. Kaewunruen, Alex M. RemennikovAbstract:Interactions between the wheel of rolling stocks and the rail often generate interfacial impact forces to railway tracks. The dynamic impact loads are of very high magnitude but short duration, and are caused by either wheel or rail abnormalities such as flat wheels, dipped rails, etc. Although the possibility of the large impact loading to cause an extreme failure to an in-situ Concrete Sleeper could be very low about once or twice in the design life cycle, the damage of track components especially for the Concrete Sleepers is often observed. The railway Sleeper is a major component of railway tracks. Its role is to distribute the load from the rails to the underlying ballast bed. Up to current knowledge, the behaviour of the in-situ prestressed Concrete Sleepers under the impact loading has not yet been thoroughl
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Publication Details
2016Co-Authors: S. Kaewunruen, Sakdirat Kaewunruen, Alexander Remennikov, Alex M. RemennikovAbstract:railway prestressed Concrete Sleeper
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Low-velocity impact analysis of railway prestressed Concrete Sleepers
2016Co-Authors: S. Kaewunruen, Sakdirat Kaewunruen, Alexander Remennikov, Alex M. RemennikovAbstract:Low-velocity impact analysis of railway prestressed Concrete Sleeper
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NONLINEAR TRANSIENT ANALYSIS OF A RAILWAY Concrete Sleeper IN A TRACK SYSTEM
International Journal of Structural Stability and Dynamics, 2008Co-Authors: Sakdirat Kaewunruen, Alex M. RemennikovAbstract:Railway Sleepers in a track system are usually subjected to a wide range of loading conditions. A critical type of loading condition that causes cracking in the railway Concrete Sleepers is the dynamic transient wheel force. The transient wheel forces are often due to wheel or rail abnormalities. This paper presents a dynamic finite element model of a railway Concrete Sleeper in a track system, aimed at raising the consideration of dynamic effects in Sleeper design. The railway Concrete Sleeper is modeled using the beam-on-elastic-foundation theory. Since in the actual tracks the ballast underneath does not provide any tensile resistance, the finite beam elements employed in this investigation take into account the bending and shear deformations, together with the tensionless nature of the elastic support. This paper places emphasis on the effect of the transient periods on the flexural responses of railway Sleepers in track systems. Using the robust finite element software STRAND7, the finite element model of the railway Concrete Sleeper was previously established and validated against experimental data by the authors. The numerical analyses present the ratio between the dynamic and the static bending moment resultants, the dynamic magnification factor, of the railway Concrete Sleeper under different sinusoidal pulse durations.
Erosha Kahawatta Gamage - One of the best experts on this subject based on the ideXlab platform.
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Structural Behaviours of Railway Prestressed Concrete Sleepers (Crossties) With Hole and Web Openings
Procedia Engineering, 2016Co-Authors: Sakdirat Kaewunruen, Erosha Kahawatta Gamage, Alexander RemennikovAbstract:Abstract As the crosstie beam in railway track systems, the prestressed Concrete Sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed Concrete has played a significant role as to maintain the high endurance of the Sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed Concrete Sleepers in railway tracks, there have always been considerable demands from rail and track engineers to improve serviceability and functionality of Concrete Sleepers. For example, signalling, fibre optic, equipment cables are often damaged either by acute ballast corners or by tamping machine operation. There has been a significant need to re-design Concrete Sleeper to cater cables internally so that they would not experience detrimental or harsh environments. Accordingly, this study is the world first to experimentally investigate the effects of holes and web openings on structural behaviours of Concrete Sleepers under rail loading condition. The modified compression field theory for ultimate strength behaviours of Concrete Sleepers will be highlighted in this study. The outcome of this study will enable the new design and calculation methods for prestressed Concrete Sleepers with holes and web opening that practically benefits civil, track and structural engineers in railway industry.
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Design of holes and web openings in railway prestressed Concrete Sleepers
2015Co-Authors: Erosha Kahawatta Gamage, Sakdirat Kaewunruen, Alexander RemennikovAbstract:As the crosstie beam in railway track systems, the prestressed Concrete Sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed Concrete has played a significant role as to maintain the high endurance of the Sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed Concrete Sleepers in railway tracks, there have always been many demands from rail engineers to improve serviceability and functionality of Concrete Sleepers. For example, signalling, fibre optic, equipment cables are often damaged either by ballast corners or by tamping machine. There has been a need to re-design Concrete Sleeper to cater cables internally so that they would not experience detrimental or harsh environments. Accordingly, this study will investigate the design criteria and effects of holes and web openings on structural capacity of Concrete Sleepers under rail loading. The modified compression field theory for ultimate strength design of Concrete Sleepers will be highlighted in this study. The outcome of this study will enable the new design and calculation methods for prestressed Concrete Sleepers with holes and web opening that practically benefits civil, track and structural engineers in railway industry. INTRODUCTION Prestressing in railway Concrete Sleepers yields endurance property under high-cycle fatigue. In practice, track engineers need to generate holes or web openings in Concrete Sleepers to enable the accommodation of cables and signalling equipment. This study aims to provide a principle understanding of the structural capacity and energy toughness of prestressed Concrete Sleepers without and with holes and web openings. It will investigate the design criteria and effects of holes and web openings on structural capacity of Concrete Sleepers under rail loading. The modified compression field theory and finite element modelling for ultimate strength design of Concrete Sleepers will be highlighted in this study. In order to meet the objectives of this investigation, four approaches will be followed. Initial stages of the study involve a cross sectional analyses of Concrete Sleepers, which will be evaluated using, both modified compression field theory and finite element modelling. Then the analysis: the provisions of existing design guidelines will be used to calculate the capacity of the Concrete Sleepers. Next step involved lap testing where, five Concrete Sleepers obtained from our industry partner will be tested under a static bending load pattern. One Sleeper will be a control sample, while the other four will be cored varying dimensions and locations. All Sleepers will be subjected to static bending tests. The loaddeflection, stress-stress, and load-rotation curves will be plotted for comparison with analytical and numerical results. Finally the parametric studies using validated numerical model will be used to develop a practical design guideline for holes and web openings in railway Concrete Sleepers. This paper will present the design criteria and effects of holes and web openings on structural capacity of Concrete Sleepers under rail loading. The modified compression field theory for ultimate strength design of Concrete Sleepers will be highlighted in this study. The effects of track environment including soft and hard tracks are also presented as to implement design guidance related to the ultimate limit state of Concrete Sleepers. The outcome of this study will enable the new design and calculation methods for prestressed Concrete Sleepers with holes and web opening that practically benefits civil, track and structural engineers in railway industry. Concrete SleeperS Sleepers are transverse beams laying on ballast and support. Wooden Sleepers were utilized as a part of the past in light of the fact that timber was promptly accessible in the neighbourhood. Nevertheless, prestressed or reinforced Concrete Sleepers, and to a restricted degree steel Sleepers, have been received in current railway tracks over the previous decades on account of their strength and long administration life [1-5]. Solid Sleepers are depicted as either twin-square or mono-piece. Inside all these sorts, Concrete Sleepers are all the more generally utilized in light of the fact that they are not influenced all that much by either atmosphere or climate. Furthermore, it provides anchorage for the fastening system and limit longitudinal, parallel and vertical movement by implanting itself onto the substructures. Figure 1 below illustrates the two types of Concrete Sleepers [1-2]. Figure 1: Concrete Sleepers (http://www.aboutcivil.org/types-of-railway-Sleepers-advantages-disadvantages.html) CROSS SECTIONAL PROPERTIES All vital cross-sectional properties and measurements of the Sleepers used in the investigation are represented below. These cross-sectional properties are used in order to calculate the moment of inertia, stress analysis of the rail seat utilizing the parallel axis theorem. Cross section 1 illustrates the Sleeper with no web openings and cross section 2 illustrates a Sleeper with a 50mm transverse hole. FLEXURAL CAPACITY The ultimate load capacity of the Sleeper design will be resolved for comparative purposes. The nominal moment capacity will likewise show the real limit of the segment or potential store limit, which the section given is permissible to crack. Once separated into standard shapes the measurements are set into a spreadsheet, since this methodology will be rehashed for every segment and configuration cycle. However, the flexural calculations are done according to both ACI and Eurocode 2 [6]. A sample of the spreadsheet utilized for the estimation of cross-sectional properties is indicated in figure 2. a) Cross section 1Sleeper with no web opening b) Cross section 2 Sleeper with 50mm transverse hole Figure 2: Cross sections of Concrete Sleepers Figure 3: Cross sectional properties of Concrete Sleeper CROSS SECTION ANALYSIS: NO WEB OPENING A: American Concrete Institute (ACI) Method A.1) Calculation of ed,max (strain in Concrete at furthest most layer of pre-stressing from extreme compression fiber at decompression condition) ed,max= fpe_RSAps Ec [ 1 Ac_RS + (dmax − yt_RS) 2
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DESIGN OF HOLES AND WEB OPENINGS IN RAILWAY PRESTRESSED Concrete SleeperS
2015Co-Authors: Sakdirat Kaewunruen, S. Kaewunruen, Erosha Kahawatta Gamage, A M RemennikovAbstract:As the crosstie beam in railway track systems, the prestressed Concrete Sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed Concrete has played a significant role as to maintain the high endurance of the Sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed Concrete Sleepers in railway tracks, there have always been many demands from rail engineers to improve serviceability and functionality of Concrete Sleepers. For example, signalling, fibre optic, equipment cables are often damaged either by ballast corners or by tamping machine. There has been a need to re-design Concrete Sleeper to cater cables internally so that they would not experience detrimental or harsh environments. Accordingly, this study will investigate the design criteria and effects of holes and web openings on structural capacity of Concrete Sleepers under rail loading. The modified compression field theory for ultimate strength design of Concrete Sleepers will be highlighted in this study. The outcome of this study will enable the new design and calculation methods for prestressed Concrete Sleepers with holes and web opening that practically benefits civil, track and structural engineers in railway industry
Sangkeun Ahn - One of the best experts on this subject based on the ideXlab platform.
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Complex structured polymer Concrete Sleeper for rolling noise reduction of high-speed train system
Composite Structures, 2019Co-Authors: Sangkeun Ahn, Semin Kwon, Yeon-taek Hwang, Hyo-in Koh, Hak-sung Kim, Junhong ParkAbstract:Abstract Damping performance of complex polymer Concrete Sleeper for high-speed trains was identified after considering the radiation characteristics of rolling noise. Actual size complex Concrete Sleepers were fabricated to compare the damping characteristics. The wave type polymer Concrete structure was embedded into the cement Concrete Sleeper. The measured dynamic properties of the complex Concrete Sleeper were compared with those of the cement Concrete Sleeper. The effects on improved damping performance due to the periodic polymer structure were investigated. The averaged dynamic properties of the Sleepers were used to prediction of the rolling noise generation. A running train on the rail track was assumed as the moving load on the infinite Timoshenko beam. The relationship between the loss factor of the supporting stiffness and the rail vibration was analyzed. The radiated sound pressure from the rail vibration was predicted for the running train. Using complexed structured Concrete Sleeper, the radiation of the rolling noise was reduced effectively. This investigation on the Concrete Sleeper embedded with wave-type polymer Concrete contributes to the study of complex railway structures to secure quite residential space with minimal influence from running trains.
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???????????????, 2018Co-Authors: Sangkeun AhnAbstract:Train system is essential transportation due to its high speed and large scale comparing with vehicle. Although train system has many benefit as above, radiated sound from train make annoyance to residents near railroad. The train noise mainly consists of aerodynamic noise, driving noise from power sources, rolling noise from wheel, rail track and Sleepers. When train running faster than 300 km/h, the aerodynamic noise becomes dominant component of the train noise. However, rolling noise contributes train noise over all speed range. To reduce rolling noise, the web damper installed on the track and the high damping pad under the track have been investigated. The web damper covers only low frequency range and rail pad causes high maintenance cost. Cement Concrete Sleeper of high speed railway is major component of the rail system. Due to flexural deflection of train and rail track, elastic characteristics of Concrete Sleeper affects vibration of rail system. High damping Concrete Sleepers are needed to solve the noise problem induced from rolling noise. Radiation characteristics of rolling noise was predicted by applying moving load theorem. Running train on rail track is modeled as moving load on infinite beam. Relationship between the loss factor of supporting stiffness and the rail vibration was analyzed. Radiated sound power and directivity of rolling noise from rail vibration were identified with different the load velocity. Concrete cement has been widely used as a material in civil engineering structures due to its flexibility and load holding capabilities. However, Portland cement Concretes have exhibited problems arising from excessive noise and vibration generation due to their low damping. In this paper, polymer Concretes made with an epoxy resin were studied and their ability to reduce noise/vibration in a Concrete slab track was examined. The polymer Concretes were fabricated with different mixing ratios of the epoxy resin/aggregate and aggregates of different sizes. The effects of these variables on the compressive and flexural strengths of the polymer Concretes were measured to study the mechanical reliability under water absorption environments. Also, the frequency dependent variations of stiffness and damping in the polymer Concretes were obtained by impact vibration tests to study their ability to reduce vibrations. The fatigue tests of the Concretes were performed by applying periodic load for bending tests. To investigate the reduction of stiffness due to fatigue damage, the frequency dependent variations of the dynamic stiffness and the loss factor of the polymer Concretes (a mixture of epoxy resin, carbon fiber and aggregates) were obtained by impact tests. The variation of the dynamic properties before and after the fatigue tests was measured. The separated beam method was used to identify the stiffness distribution along the Concrete specimen. This method analyzed the beam vibration using evenly spaced beam elements. The boundary conditions of displacement and slope continuity at end of each element were imposed. The least square method was applied to estimate the dynamic properties of the beam elements from the measured vibration response. This procedure was required to identify small change in the dynamic properties induced during fatigue tests. Consequently, the durability of the carbon fiber reinforced polymer Concretes was validated by comparison with normal polymer Concretes. A pipe structure was embedded in polymer Concrete specimens. The frequency-dependent variations of the dynamic stiffness and the loss factors of the specimens were measured by the vibration test method so that the damping enhancement from the embedded structure could be identified. The weight reduction effect of epoxy resin usage was compared after pipe embedment. Impact dampers were applied to the pipe-embedded polymer Concretes to improve their vibrational energy dissipation. The impact dampers were fabricated through the insertion of impact balls into the pipe structures. The dynamic properties of the impact-damper-positioned polymer Concretes were obtained by vibration tests. The damping performance was investigated according to the gap size between the impact ball and the pipe. An analytic model was used to predict the vibrational behavior of the polymer Concrete when the impact dampers were applied. Consequently, the effect on vibration damping was identified for different mass ratios and gaps to find optimal construction. As another way to improve damping performance of the Concrete Sleeper, complex Concrete which is polymer Concrete was inserted in cement Concrete was fabricated. The adhesion force at the interface between the polymer Concrete and the cement Concrete was investigated from impact test. A cylindrical embedment structure was fabricated by using a silicon mold and the embedment was placed in direction of length and height. From the cylindrical embedment, more suitable embedment shape was determined by measuring the flexural strength and the loss factor. A wave type embedment structure was designed in order to improve the performance of the complex Concrete. With the longitudinal direction, the height of the polymer Concrete change continuously. The responses of the complex Concretes were also measured using accelerometers by impact excitation. The characteristics of the metamaterial was identified from the periodic nonlinear interface. An analysis model considering the classical laminate theorem to investigate the damping effect of wave type embedment was imposed. To verify the damping performance of meta-structured Concrete, actual size meta-structured Concrete Sleeper was fabricated. The averaged loss factor of the complex Sleeper in frequency range from 50 Hz to 3.2 kHz was compared with that of the cement Concrete Sleeper. It was found that the meta structure using the polymer Concrete wave pattern is also effective in improving damping performance of an actual Concrete Sleeper. Lastly, the dynamic properties of the measured complex Concrete were applied to the rolling noise analysis model. The rolling noise form railway in velocity of 300 km/h was analyzed. Using meta-structured Concrete Sleeper, the radiation of the rolling noise was reduced effectively. This investigation on the characteristics of Concrete Sleeper embedding wave type polymer Concrete contributes to study of complex slab railway structures to minimize the vibration and noise generation from running trains.Docto
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investigation of damping in the polymer Concrete Sleeper for use in reduction of rolling noise from railway
Journal of the Acoustical Society of America, 2014Co-Authors: Sangkeun Ahn, Hak-sung Kim, Junhong Park, Eunbeom Jeon, Hyoin KhoAbstract:The purpose of this study was to measure damping of various polymer Concretes to be used as Sleepers for railway. The polymer Concretes consisted of epoxy monomer, hardener and aggregates. Various polymer Concrete specimens were made by changing epoxy resin weight ratio and curing temperature. The dynamic properties of the polymer Concrete specimens were measured by using beam-transfer function method. To predict reduction performance of the polymer Concrete Sleepers, an infinite Timoshenko beam model was investigated after applying measured Concrete properties. The moving loads from rotating wheels on railway due to different roughness were utilized in railway vibration analysis. The vibration response was predicted from which the effects of supporting stiffness and loss factor of Sleeper were investigated. The radiated sound power was predicted using calculated rail vibration response. Consequently, the sound power levels were compared for rails supported by different polymer Concrete Sleepers. The result of this study assists constructing low noise railway.