Experimental investigation into the effect of steel sleeper vertical stiffeners on railway track lateral resistance

2016 ◽  
Vol 231 (1) ◽  
pp. 104-110 ◽  
Author(s):  
Jabbar-Ali Zakeri ◽  
Roshan Talebi
Keyword(s):  
Experimental Investigation ◽  
Lateral Displacement ◽  
New Method ◽  
Railway Track ◽  
Experimental Investigations ◽  
Lateral Resistance ◽  
Ballasted Track ◽  
Web Stiffeners

Continuously welded rails are a common remedy to prevent rail defects, including railhead batter, rail cracking or breakage, and lateral displacement of track, among others. However, at curves with a radius of less than 400 m, rail welding is practically impossible due to the lack of track lateral resistance. Therefore, finding a new method to increase the track lateral resistance is necessary to facilitate rail welding, especially on tracks with steel sleepers. This study proposes a new method of increasing the lateral resistance of a ballasted track with steel sleepers by using web stiffeners. The effect of such stiffeners is investigated through a comparison with tracks having regular steel sleepers. The single tie (sleeper) push test is used in this research. The results of the experimental investigations show that the lateral resistance increases by 24, 140, and 203 percent, respectively, with the use of one, two, and three web stiffeners under the steel sleeper compared with a steel sleeper without stiffeners. Thus, the use of two stiffeners is concluded to provide enough lateral resistance in the case of older tracks. Therefore, the welding of rails at tight curves becomes conceivable.

scholarly journals Field Investigations on the Effects of Track Lateral Supports on the Ballasted Railway Lateral Resistance

2020 ◽  
Author(s):  
Jabbar Ali Zakeri ◽  
Milad Alizadeh Galdiani ◽  
Seyed Ali Mosayebi
Keyword(s):  
Numerical Modeling ◽  
Bilinear Form ◽  
Field Tests ◽  
New Method ◽  
Railway Track ◽  
Lateral Forces ◽  
Lateral Resistance ◽  
Field Investigations ◽  
Continuous Welded Rail ◽  
Lateral Displacements

Lateral movements of the ballasted railway track especially in the continuous welded rail (CWR) occur in sharp curves because of high lateral forces. Several strategies have been proposed to increase the track lateral resistance which most of them related to track curves with small radii. In this paper, track lateral supports as a new method have been utilized and a series of field tests have been conducted by using the Single Tie Push Tests (STPT) and Multi Tie Push Tests (MTPT) and their results are compared with the numerical modeling. The results of numerical modeling and field tests show that the track lateral resistance significantly increases in the railway with lateral supports, so that the lateral displacements of track are as a bilinear form.

scholarly journals Identification of Track Stability Model Parameters Based on Numerical Experiments

2022 ◽  
Vol 12 (2) ◽  
pp. 570
Author(s):  
Dorota Błaszkiewicz-Juszczęć ◽  
Włodzimierz Czyczuła ◽  
Dariusz Kudła
Keyword(s):  
Numerical Model ◽  
Lateral Displacement ◽  
Railway Track ◽  
Model Parameters ◽  
Lateral Resistance ◽  
Stability Model ◽  
Deformation Work ◽  
Energy Equilibrium ◽  
Lateral Displacements ◽  
Two Parameters

In the article, an identification method of railway track stability model parameters based on energy equilibrium is presented by the authors. A study of two parameters directly influencing the continuous welded track (CWR) stability is described by the authors, i.e., the rail-sleeper structure stiffness Bz is considered one beam, and the ballast lateral resistance r0. These parameters were estimated with the use of a numerical model for various railway track types. The adopted concept is based on the assumption that it is possible to determine substitute values for both parameters. Therefore, using one value of both of these parameters, we label them substitute parameters. The assumed numerical model forced lateral displacements of a track section, and, based on the obtained track section displacement results, energy equilibrium was determined. The equilibrium takes into account the work of external load and the bending work of rail-sleeper structure with the substitute stiffness Bz and the ballast deformation work, also with the substitute value of lateral resistance r0 with lateral displacement. The aim is to identify these substitute values to be used for analysing track stability with the semi-analytical model. These analyses are part of the studies related to the development of a method of assessing various methods of increasing track stability.

scholarly journals The practice of experimental investigations of lexical tones in Baltic subdialects: some of the new insights in methodology

2020 ◽  
pp. 1-19
Author(s):  
Evaldas Švageris
Keyword(s):  
Experimental Investigation ◽  
Methodological Approach ◽  
Main Idea ◽  
Experimental Investigations ◽  
Lexical Tone ◽  
Mathematical Functions ◽  
Combined Analysis ◽  
Lexical Tones ◽  
Acoustic Correlates ◽  
The Baltic

This article provides an alternative way of experimental investigation of lexical tones in the Baltics. The main idea holds on a presupposition that the phonetic basis of prosodic elements in question can be explained in a more appropriate way in terms of a combined analysis of acoustic correlates, rather than a selective one. The lexical tone in this case may be interpreted as a factor which determines the type of acoustic correlation. Ideally, the interdependence of that sort could be defined by mathematical functions. The analysis of the empirical basis provides clear evidence in the favour of such methodological approach. Phonetic data from both, the Latvian (Valmiera) and the Lithuanian (North Žemaitian) subdialects confirmed clearly that the highest level of the tone distinction can be reached by a combined analysis of the pitch slope, pitch jerk and the duration of the long accented vowels. These results have arguably improved the interpretation of the phonetic tone structure and shed a new light on the typological links between the Baltic dialects. Finally, it presupposes that the phonetic nature of prosodic elements in some degree depends on a methodological way we choose for the investigational purposes. 

scholarly journals Experimental investigations of the performance of a thermoacoustic electricity generator

2019 ◽  
Vol 116 ◽  
pp. 00025
Author(s):  
Ahmed Hamood ◽  
Artur Jaworski
Keyword(s):  
Experimental Investigation ◽  
Acoustic Wave ◽  
Load Resistance ◽  
Experimental Investigations ◽  
The Novel ◽  
Working Medium ◽  
Linear Alternator ◽  
Mean Pressure ◽  
Set Up ◽  
Working Parameters

This paper presents the experimental investigation of a two-stage thermoacoustic electricity generator able to convert heat at the temperature of the exhaust gases of an internal combustion into useful electricity. The novel configuration is one wavelength and consists of two identical stages. The identical stages will have out of phase acoustic wave at similar amplitudes which allows coupling a linear alternator to run in push-pull mode. The experimental set-up is 16.1 m long and runs at 54.7 Hz. The working medium is helium at 28 bar. The maximum generated electric power is 73.3 W at 5.64% thermal-to-electric efficiency. The working parameters including load resistance, mean pressure and heating power were investigated.

scholarly journals The experimental validation of a numerical model for the receptance prediction

2019 ◽  
Vol 286 ◽  
pp. 01007
Author(s):  
A. Zougari ◽  
J. MartÍnez
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Model ◽  
Experimental Validation ◽  
Parametric Design ◽  
Experimental Methodology ◽  
Railway Track ◽  
Experimental Result ◽  
Ballasted Track ◽  
Ansys Parametric Design Language

The traditional ballasted track with wooden sleepers covers today most railway lines constructions, including the tracks of tram and metro or the industrial railway branching. In this work, we present an experimental methodology to validate a numerical model based on finite element method, the model was previously well defined using the ANSYS Parametric Design Language (APDL) and adapted to represent a classical ballasted track. The obtained result of the analysis is expressed as a frequency response of the track and it is compared to the experimental result from measurements made on the metropolitan classical railway track of Barcelona.

Three-Dimensional Nonlinear Stability Analysis of Tangent Continuous Welded Rail Track Under Temperature and Mechanical Loads

1997 ◽  
Vol 1584 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Yulin Bao ◽  
Ernest J. Barenberg
Keyword(s):  
Stability Analysis ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Initial Slope ◽  
Lateral Loads ◽  
Rotational Stiffness ◽  
Geometric Imperfections ◽  
Mechanical Loads ◽  
Lateral Resistance ◽  
Continuous Welded Rail

Results from applications of the three-dimensional continuous welded rail (CWR) track model ILLIBUCKLE to a tangent CWR track with nonlinear resistance and lateral geometric imperfections are presented. Stability analysis is made of the tracks under temperature and mechanical loads by using temperature lateral-displacement curves. Tangent CWR track stability is highly sensitive not only to ballast lateral resistance and geometric imperfections of the the initial track but also to the vertical rotational stiffness in rail-pad fastener systems and vehicle lateral loads. It is concluded that not only the peak values but also the initial slope and the limit resistance in the ballast lateral-resistance curve obtained from a single-tie push test are important in evaluation of track stability. With regard to vertical rotational stiffness in a rail-pad fastener system, track stability is not significantly affected by the nonlinearities, but it is affected by the initial slope. Effects of the combination of mechanical and thermal loads on tangent track stability are presented. The reduction of ballast lateral resistance due to the uplift of rail tie under vehicle vertical loads as well as the magnitude of vehicle lateral loads significantly decrease track stability. A 1400-kg vehicle lateral load can buckle tangent CWR track under a rail-temperature increase as low as 56°C (100°F) under unfavorable conditions.

Suggestion for allowable additional compressive stress based on track conditions

2017 ◽  
Vol 232 (5) ◽  
pp. 1309-1325 ◽  
Author(s):  
Kyung-Min Yun ◽  
Beom-Ho Park ◽  
Hyun-Ung Bae ◽  
Nam-Hyoung Lim
Keyword(s):  
Compressive Stress ◽  
Structural Characteristics ◽  
Three Dimensional ◽  
Additional Stress ◽  
Analysis Model ◽  
Temperature Changes ◽  
Lateral Resistance ◽  
Ballasted Track ◽  
Continuous Welded Rail ◽  
Track Bridge

A continuous welded rail has immovable zones due to its structural characteristics. In an immovable zone, thermal expansion and contraction of rails are restricted when the temperature changes, thereby causing excessive axial force on the rail. When the immovable zone of the continuous welded rail is located on a bridge, additional stress and displacement occur through track–bridge interactions. Additional stress and displacement of the rail compared to the embankment area are restricted when constructing the bridge under the continuous welded rail track to prevent problems with the track–bridge interaction according to UIC 774-3R and Euro codes. According to the various codes, the maximum allowable additional compressive stress is 72 MPa, with the conditions of a curve with a radius (R) ≥ 1500 m, UIC 60 continuous welded rail (tensile strength of at least 900 MPa), ballasted track with concrete sleepers and 30 cm of deep for a well-consolidated ballast. However, the lateral resistance that has the greatest effect on track stability can depend on the conditions mentioned above. Therefore, an additional review of various track conditions is required. In this paper, an evaluation of the current criteria was performed using the minimum buckling strength calculation formula, and the allowable additional stress on the rail suggested by codes could only be used on tracks with a large lateral resistance above 18 kN/m/track. Thus, a three-dimensional nonlinear analysis model was developed and analyzed to calculate the allowable additional compressive stress considering various track conditions. According to the results of the analysis, the allowable additional compressive stress was reduced with a comparatively small lateral resistance. The freedom of design can be enhanced with respect to the parameters of various track and bridge conditions using this model.

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