scholarly journals Laboratory Tests and Analyses of the Level of Vibration Suppression of Prototype under Ballast Mats (UBM) in the Ballasted Track Systems

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 313
Author(s):  
Cezary Kraśkiewicz ◽  
Artur Zbiciak ◽  
Kacper Wasilewski ◽  
Anna Al Sabouni-Zawadzka
Keyword(s):  
Mechanical Model ◽  
Laboratory Tests ◽  
Vibration Suppression ◽  
Track Structure ◽  
European Standard ◽  
Static And Dynamic Characteristics ◽  
Vibration Isolators ◽  
Testing Procedures ◽  
Ballasted Track ◽  
German Standard

The present paper is aimed at the analysis of under ballast mats (UBM) which are used in ballasted track structures as vibration isolators and to protect the ballast layer against fast degradation. The mats were tested in the laboratory and afterwards a novel 4-DoF mechanical model of the track structure with UBM was developed. The novelty of this study consists in the comparison of two testing procedures: a procedure based on the popular German standard DIN 45673-5 and a new European standard EN 17282, released in October 2020. Major discrepancies were demonstrated in the determined values of the static and dynamic characteristics using both approaches—especially in reference to the mats with higher stiffness.

scholarly journals A Novel Approach to the Analysis of Under Sleeper Pads (USP) Applied in the Ballasted Track Structures

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2438 ◽  
Author(s):  
Artur Zbiciak ◽  
Cezary Kraśkiewicz ◽  
Anna Al Sabouni-Zawadzka ◽  
Jan Pełczyński ◽  
Sławomir Dudziak
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Mechanical Model ◽  
Rheological Model ◽  
Laboratory Tests ◽  
Vibration Isolation ◽  
Special Focus ◽  
Vibration Isolators ◽  
Novel Approach ◽  
Ballasted Track

The present paper is dedicated to the analysis of under sleeper pads (USP), which are resilient elements used in ballasted track systems as vibration isolators. Four types of USP are considered. The authors present the results of laboratory tests, which are then used as input values for the finite element (FE) and mechanical model of the structure. A special focus is put on the description of an original four-degree-of-freedom (4DoF) mechanical model of the system that includes a fractional rheological model of USP. Using the proposed approaches, the dynamic characteristics of under sleeper pads are determined, and conclusions on vibration isolation effectiveness are drawn.

Energy flow and performance evaluation of inerter-based vibration isolators mounted on finite and infinite flexible foundation structures

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402110704
Author(s):  
Zhuang Dong ◽  
Jian Yang ◽  
Chendi Zhu ◽  
Dimitrios Chronopoulos ◽  
Tianyun Li
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Flow Behavior ◽  
Flexible Beam ◽  
Vibration Isolators ◽  
Force Transmissibility ◽  
And Performance ◽  
Flexible Foundation ◽  
Isolation Performance

This study investigates the vibration power flow behavior and performance of inerter-based vibration isolators mounted on finite and infinite flexible beam structures. Two configurations of vibration isolators with spring, damper, and inerter as well as different rigidities of finite and infinite foundation structures are considered. Both the time-averaged power flow transmission and the force transmissibility are studied and used as indices to evaluate the isolation performance. Comparisons are made between the two proposed configurations of inerter-based isolators and the conventional spring-damper isolators to show potential performance benefits of including inerter for effective vibration isolation. It is shown that by configuring the inerter, spring, and damper in parallel in the isolator, anti-peaks are introduced in the time-averaged transmitted power and force transmissibility at specific frequencies such that the vibration transmission to the foundation can be greatly suppressed. When the inerter is connected in series with a spring-damper unit and then in-parallel with a spring, considerable improvement in vibration isolation can be achieved near the original peak frequency while maintaining good high-frequency isolation performance. The study provides better understanding of the effects of adding inerters to vibration isolators mounted on a flexible foundation, and benefits enhanced designs of inerter-based vibration suppression systems.

scholarly journals Influence of the use of spring vibration isolators in the construction of track pavement for damping vibrations from the track

2018 ◽  
Vol 2018 (5) ◽  
pp. 1-9
Author(s):  
Ewelina Kwiatkowska ◽  
Wiesław Fiebig
Keyword(s):  
Noise Reduction ◽  
Vibration Isolation ◽  
New Technology ◽  
Track Structure ◽  
Vibration Isolators ◽  
Isolation Systems ◽  
Tuning Frequency ◽  
Mass Spring ◽  
Lower Frequencies

The paper presents tuned track bed vibration isolation systems used for the railway and tramway lines. The presented solution based on mass spring systems and is effective especially at lower frequencies. The tuning frequency of such systems is mostly in the range 5 to 8 Hz. With measures based on spring elements elaborated by GERB company the significant vibration and noise reduction coming from the railways and tramways can be achieved. This new technology in Poland can be used during the track structure modernization as well as in the new projects, in which the track bed vibration isolation is required.

Constitutive Behavior and Testing of Structural Adhesives

1987 ◽  
Vol 40 (10) ◽  
pp. 1393-1402 ◽  
Author(s):  
Erol Sancaktar
Keyword(s):  
Mechanical Model ◽  
Material Characterization ◽  
Constitutive Relations ◽  
Superposition Principle ◽  
Surface Preparation ◽  
Ring Test ◽  
Stress Strain ◽  
Testing Procedures ◽  
Structural Adhesives

Material characterization of structural adhesives in the bulk and bonded forms is discussed. Constitutive relations used for describing stress–strain data are reviewed. The difficulties associated with adhesive characterization in the bonded form are cited. Common testing procedures for adhesive characterization in the bulk and bonded forms are reviewed. In presenting the constitutive relations used in material characterization of structural adhesives, deformation theories introduced by Hencky are reviewed first. The modifications made in this theory to render it rate dependent and bilinear are discussed and applications to adhesive characterization are cited. Application of linear viscoelasticity, mechanical model characterization, and its use in describing the dependence of adhesive and cohesive strengths on rate, temperature, and bond thickness are presented. The time–temperature superposition principle and three-dimensional stress–strain relations in integral and differential operator forms are reviewed. Frequent assumptions for dilatation and distortion operations are presented. Procedures for describing nonlinear viscoelastic behavior are reviewed. It is pointed out that the extent of nonlinearity is dependent on both the stress level and the time scale. The use of nonlinear spring and dashpot elements, nonlinear differential operators, and perturbation of elastic and viscous coefficients are cited. Prandtl’s incremental theory of plasticity and its extension in the form of over-stress theory is presented. The incorporation of this over-stress idea into the viscoelastic mechanical model characterization is discussed. The modified Bingham model and the Chase–Goldsmith model developed in this fashion and their application to adhesive material characterization are presented. The use of empirical relations for the description of creep behavior is discussed. Prediction of shear behavior based on bulk tensile data is demonstrated. It is suggested that characterization of adhesive behavior in the bonded form should include the application of stress analysis, fracture mechanics, polymer chemistry and surface analysis techniques. In testing bonded samples the use of thick adherend symmetric single lap geometry or napkin ring test geometry is advised and it is suggested that the specimens should be prepared with the same surface preparation and cure techniques.

scholarly journals Validation of a thermo-hydro-mechanical model of freezing of water-saturated soil based on laboratory tests results

2021 ◽  
Vol 14 (2) ◽  
pp. 144-158
Author(s):  
M.S. Zhelnin ◽  
A.A. Kostina ◽  
A.E. Prokhorov ◽  
O.A. Plekhov ◽  
M.A. Semin ◽  
...  
Keyword(s):  
Mechanical Model ◽  
Laboratory Tests ◽  
Saturated Soil ◽  
Water Saturated

Vibration Suppression Performance of a Desktop Vibration Isolator Supported by Four Air Spring

2017 ◽  
Author(s):  
Yuichi Baba ◽  
Kento Onishi ◽  
Toshihiko Asami
Keyword(s):  
Support System ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Theoretical Calculations ◽  
Small Diameter ◽  
Measuring Instruments ◽  
Vibration Isolator ◽  
Air Spring ◽  
Damping Force ◽  
Vibration Isolators

Desktop vibration isolators are often used as precision measuring instruments. This article discusses the accuracy of performance prediction methods for vibration isolators elastically supported by four air springs. Each air spring possesses a reservoir tank to ensure the natural frequency of the support system remains low and to provide adequate damping force. For practical use, air springs and reservoir tanks should be installed in separate locations and connected by a small-diameter pipe because desktop isolators must be thin. Our previous studies have shown that there is a secondary resonance point in systems supported by air springs with long pipes and reservoir tanks and that it is not simple to theoretically calculate the amplitude and frequency at this point because this type of air spring support system has nonlinear characteristics. In this study, the change in the vibration isolation performance of a desktop vibration isolator with the length of the pipe connecting the main air tank and the reservoir tank of an air spring-supported system was examined experimentally and approximated using theoretical calculations.

scholarly journals Numerical analysis of beam rail bridges with random track irregularities

2018 ◽  
Vol 196 ◽  
pp. 01050
Author(s):  
Monika Podwórna
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Concrete Bridges ◽  
Track Structure ◽  
Simply Supported ◽  
Ballasted Track ◽  
High Speed Trains ◽  
Composite Bridge ◽  
Random Track Irregularities ◽  
Track Irregularities

The study focuses on dynamic analysis of composite bridge / track structure / train systems (BTT systems) with random vertical track irregularities taken into consideration. The paper presents the results of numerical analysis of advanced virtual models of series-of-types of single-span simply-supported railway steel-concrete bridges (SCB) with symmetric platforms, located on lines with the ballasted track structure adapted to traffic of high-speed trains.

Variations in Testing Procedures on the Rotary Flexometer

1976 ◽  
Vol 49 (2) ◽  
pp. 258-277 ◽  
Author(s):  
P. Kainradl ◽  
F. Wolf ◽  
H. Ecker
Keyword(s):  
Fatigue Resistance ◽  
Heat Generation ◽  
Test Method ◽  
Force Amplitude ◽  
Severity Factor ◽  
Testing Procedures ◽  
Deformation Amplitude ◽  
German Standard ◽  
Constant Deformation ◽  
Specimen Center

Abstract The rotary flexometer described in German Standard Proposal DIN 53 533 has been used to determine heat generation and fatigue resistance on homogeneous rubber specimens, laminated specimens, and some containing fabric plies. When a series of compounds having a range of hysteresis or hardness is run at constant deformation amplitude, the ranking is usually inverse to that obtained when run at constant force amplitude. The test method should be chosen to correspond to the proposed use of the compound. Accessories developed permit testing of 10 ×. 10 mm cylindrical specimens as well as conventional 20 × 20 mm cylinders. Temperature measurements in the specimen center have proven to be more precise than those on the free surface or on a clamped surface. Temperature increase during cycling is strictly a function of the viscoelastic properties of the compound. Creep measured at ambient temperature may rate a series of compounds differently than if measured at an elevated temperature. Fatigue resistance is well represented by S-N curves where the logarithm of N, the cycles to failure is plotted as a function of S, the severity factor (deformation amplitude or force amplitude). An inverse relationship exists between rate of heat generation and failure by degradation of the specimen center. The vulcanization system affects fatigue life. The temperature reached during testing of a highly hysteretic material can be minimized by using it as the central layer of a laminated specimen and higher hysteretic materials for the rest of the specimen. The apparatus can be used for testing dynamic adhesion fatigue of rubber-fabric bonds. Failure between plies started as a failure of the bond between rubber and cord.

scholarly journals Diagnostics of Track Quality of Ballastless Track and Transition Areas in Vicinity of Portals of Tunnel Turecky vrch

2016 ◽  
Vol 12 (1) ◽  
pp. 2-12 ◽  
Author(s):  
Michal Šmalo
Keyword(s):  
Track Structure ◽  
Track Geometry ◽  
Ballastless Track ◽  
Ballasted Track ◽  
Transition Areas ◽  
Track Quality

Abstract The paper deals with the partial results of diagnostics of experimental sections of ballastless track Rheda 2000® and transition areas between ballastless and ballasted track structure around portals of tunnel Turecky vrch after six measurement cycles. The paper presents differences between each operational measurement and the measurement before putting sections into operation, which indicates a development of track geometry quality.

Critical appraisal of the cone penetration method of determining soil plasticity

2006 ◽  
Vol 43 (8) ◽  
pp. 884-888 ◽  
Author(s):  
K Prakash ◽  
A Sridharan
Keyword(s):  
Laboratory Tests ◽  
Critical Appraisal ◽  
Soil Classification ◽  
Liquid Limit ◽  
Cone Penetration ◽  
Soil Plasticity ◽  
Testing Procedures ◽  
Thread Rolling ◽  
Rolling Method ◽  
Undrained Strength

Plasticity is a characteristic feature that all plastic soils possess. It is shown that the soil plasticity is mainly due to undrained cohesion. Soil plasticity characteristics obtained from laboratory tests are reasonable for use only when the testing procedures adopted to determine them measure the factors responsible for the soil plasticity. It is shown that this is the case with the percussion method of liquid limit determination and the 3 mm thread rolling method of plastic limit determination. Further, it is also shown that the results obtained from the cone penetration method cannot represent the soil plasticity fully, as the mechanisms that come into play during testing relate to undrained strength due to both undrained cohesion and undrained friction. It is stressed that the percussion and 3 mm thread rolling methods must be the only ones used to determine the plasticity of soils. The circumstance under which the cone penetration method can be used is also indicated.Key words: clays, laboratory tests, plasticity, soil classification.

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