scholarly journals Experimental Study on Vibration Characteristics of Unit-Plate Ballastless Track Systems Laid on Long-Span Bridges Using Full-Scale Test Rigs

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1744 ◽  
Author(s):  
Weiqi Zheng ◽  
Xingwang Sheng ◽  
Zhihui Zhu ◽  
Tianjing Luo ◽  
Zecheng Liu
Keyword(s):  
High Speed ◽  
Vibration Characteristics ◽  
Full Scale ◽  
Long Span Bridges ◽  
Isolation Layer ◽  
Long Span ◽  
Ballastless Track ◽  
Excited Vibration ◽  
Scale Test ◽  
Reduction Effect

In this work, we present a series of hammering tests on full-scale unit-plate ballastless tracks used for long-span bridges. There is no denying that it is a new attempt to pave ballastless tracks on high-speed railway long-span bridges; the related issues deserve to be studied, and especially the vibration characteristics. Hence, the vibration characteristics and transmission rules of the ballastless track with geotextile or rubber isolation layers are explored, and the vibration reduction effect of the rubber isolation layer is analyzed. The main conclusions are as follows: the isolation layers change vibration modes and transmission characteristics of ballastless tracks; the introduction of the rubber isolation layer makes the excited vibration frequency range of the ballastless track concentrated; and the vibrations of the ballastless track with the rubber isolation layers are stable. Moreover, the rubber isolation layer has an obvious attenuation effect on vibration transmission in ballastless track structures. When the vibration is transmitted from the rail to the bridge deck, the vibration level differences of the ballastless track with rubber isolation layers are 20 dB larger than that of the ballastless track with the geotextile isolation layers. The vibration attenuation rate of the rubber isolation layer is about ten times larger than that of geotextile isolation layer.

scholarly journals Analysis of the Vibration Characteristics of Ballastless Track on Bridges Using an Energy Method

2020 ◽  
Vol 10 (7) ◽  
pp. 2289 ◽  
Author(s):  
Hanwen Jiang ◽  
Liang Gao
Keyword(s):  
Energy Method ◽  
High Speed ◽  
Power Flow ◽  
Evaluation Method ◽  
Flow Theory ◽  
Vibration Characteristics ◽  
Vibration Energy ◽  
Ballastless Track ◽  
Track Bridge ◽  
Bridge System

Although the high-speed railway (HSR) system has been widely agreed to be a sustainable and convenient means of transportation, the vibration induced has already been deemed an urgent environmental problem. For the sake of investigating the vibration characteristics of the ballastless track on bridges in the HSR system from the point of view of energy, a numerical model of the vehicle–track–bridge coupled system is developed herein and the energy method based on power flow theory is employed. In addition, a corresponding evaluation method of the power flow theory is developed to evaluate the vibration characteristics of the track–bridge system. The conclusions indicate that (1) the vibration energy gradually attenuates from top to bottom of the track–bridge system in its transfer process. Moreover, the attenuation effects are mainly the result of the elasticity and damping effects of the fasteners and the slab mat layer. (2) With increasing slab mat layer stiffness, the vibration energy of the rail slightly decreases; on the contrary, that of the slab track and the bridge obviously increases. (3) With increasing fastener stiffness, the vibration energy of the entire track–bridge system increases. (4) With increasing running speed, the vibration energy of the entire track–bridge system rises obviously. The results reveal that the reasonable stiffness levels of the fasteners and the slab mat layer are 40 to 60 kN/mm and 40 to 60 MPa/m, respectively, under the investigated condition in this work. This work also presents a novel way to study the vibration characteristics of the ballastless track on bridges of HSRs in terms of energy.

A new methodology for the assessment of the running resistance of trains without knowing the characteristics of the track: Application to full-scale experimental data

2018 ◽  
Vol 232 (6) ◽  
pp. 1814-1827 ◽  
Author(s):  
Claudio Somaschini ◽  
Tommaso Argentini ◽  
Daniele Rocchi ◽  
Paolo Schito ◽  
Gisella Tomasini
Keyword(s):  
High Speed ◽  
High Capacity ◽  
Full Scale ◽  
Design Stage ◽  
Resistance Force ◽  
Full Scale Test ◽  
High Speed Trains ◽  
Scale Test ◽  
Full Scale Tests ◽  
Resistance Coefficients

The resistance to motion of trains is an essential requisite especially while designing high-speed trains and high-capacity railway lines. The optimisation of friction effects and aerodynamic performance can be done during the design stage of a new train but the actual value of the running resistance can be inferred only by means of full-scale tests during the operation of a train. A CEN standard (EN 14067-4) describes the methodologies for the assessment of the running resistance of railway vehicles starting from full-scale test measurements. According to this standard, the speed-dependent terms of the resistance force have to be determined by means of coasting tests on railway lines, whose characteristics must be well known. Since this is not always possible and small errors on the gradient could lead to major uncertainties in the evaluation of the resistance force, a new method for the estimation of the running resistance coefficients, irrespective of the characteristics of the track is proposed in this paper. The reliability of the method is verified by comparing the results with those obtained from the procedure proposed in the CEN standard. The comparison shows that the new methodology is able to evaluate the resistance coefficients with an accuracy equivalent to that of the other methods but with fewer tests and with a more robust procedure relying on a lesser number of parameters.

scholarly journals Full-scale multi-functional test platform for investigating mechanical performance of track–subgrade systems of high-speed railways

2020 ◽  
Vol 28 (3) ◽  
pp. 213-231
Author(s):  
Wanming Zhai ◽  
Kaiyun Wang ◽  
Zhaowei Chen ◽  
Shengyang Zhu ◽  
Chengbiao Cai ◽  
...  
Keyword(s):  
High Speed ◽  
Mechanical Performance ◽  
Full Scale ◽  
Functional Test ◽  
Railway Track ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Railway Infrastructure ◽  
Test Platform

Abstract Motivated by the huge practical engineering demand for the fundamental understanding of mechanical characteristics of high-speed railway infrastructure, a full-scale multi-functional test platform for high-speed railway track–subgrade system is developed in this paper, and its main functions for investigating the mechanical performance of track–subgrade systems are elaborated with three typical experimental examples. Comprising the full-scale subgrade structure and all the five types of track structures adopted in Chinese high-speed railways, namely the CRTS I, the CRTS II and the CRTS III ballastless tracks, the double-block ballastless track and the ballasted track, the test platform is established strictly according to the construction standard of Chinese high-speed railways. Three kinds of effective loading methods are employed, including the real bogie loading, multi-point loading and the impact loading. Various types of sensors are adopted in different components of the five types of track–subgrade systems to measure the displacement, acceleration, pressure, structural strain and deformation, etc. Utilizing this test platform, both dynamic characteristics and long-term performance evolution of high-speed railway track–subgrade systems can be investigated, being able to satisfy the actual demand for large-scale operation of Chinese high-speed railways. As examples, three typical experimental studies are presented to elucidate the comprehensive functionalities of the full-scale multi-functional test platform for exploring the dynamic performance and its long-term evolution of ballastless track systems and for studying the long-term accumulative settlement of the ballasted track–subgrade system in high-speed railways. Some interesting phenomena and meaningful results are captured by the developed test platform, which provide a useful guidance for the scientific operation and maintenance of high-speed railway infrastructure.

Full-scale fatigue test of unit-plate ballastless track laid on long-span cable-stayed bridge

2020 ◽  
Vol 247 ◽  
pp. 118601
Author(s):  
Xing-Wang Sheng ◽  
Wei-Qi Zheng ◽  
Zhi-Hui Zhu ◽  
Yong-Ping Qin ◽  
Jian-Guang Guo
Keyword(s):  
Fatigue Test ◽  
Full Scale ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Ballastless Track

Properties of rubber under-ballast mat used as ballastless track isolation layer in high-speed railway

2020 ◽  
Vol 240 ◽  
pp. 117822 ◽  
Author(s):  
Xing-Wang Sheng ◽  
Wei-Qi Zheng ◽  
Zhi-Hui Zhu ◽  
Tian-Jing Luo ◽  
Yan-Huang Zheng
Keyword(s):  
High Speed ◽  
High Speed Railway ◽  
Isolation Layer ◽  
Ballastless Track

Performance Prediction of a 112m Wave-Piercing Catamaran

2018 ◽  
Vol Vol 160 (A4) ◽  
Author(s):  
E Kay ◽  
J Lavroff ◽  
M R Davis
Keyword(s):  
High Speed ◽  
Water Jet ◽  
Full Scale ◽  
Test Results ◽  
Model Scale ◽  
Shaft Power ◽  
High Froude Number ◽  
Scale Test ◽  
Power Measurements ◽  
Surrounding Fluid

The prediction of power required to propel a high-speed catamaran involves the hydrodynamic interactions between the hull surface and the surrounding fluid that may be difficult to compute numerically. In this study model-scale experiments are used as a basis for comparison to full-scale sea trials data measured on a 112m Incat wave-piercing catamaran to predict the full-scale powering requirements from model-scale testing. By completing water jet shaft power measurements on an Incat vessel during sea trials, comparison of these results was made to model-scale test results to provide good correlation. The work demonstrates that the International Towing Tank Conference (ITTC) extrapolation techniques used provide a good basis for extrapolating the data from model-scale to full-scale to predict the power requirements for the full-scale catamaran vessel operating at high Froude Number with water jet propulsion. This provides a useful tool for future designers and researchers for determining the power requirements of a catamaran vessel through model tests.

PERFORMANCE PREDICTION OF A 112M WAVE-PIERCING CATAMARAN

2021 ◽  
Vol 160 (A4) ◽  
Author(s):  
E Kay ◽  
J Lavroff ◽  
M R Davis
Keyword(s):  
High Speed ◽  
Water Jet ◽  
Full Scale ◽  
Test Results ◽  
Model Scale ◽  
Shaft Power ◽  
High Froude Number ◽  
Scale Test ◽  
Power Measurements ◽  
Surrounding Fluid

The prediction of power required to propel a high-speed catamaran involves the hydrodynamic interactions between the hull surface and the surrounding fluid that may be difficult to compute numerically. In this study model-scale experiments are used as a basis for comparison to full-scale sea trials data measured on a 112m Incat wave-piercing catamaran to predict the full-scale powering requirements from model-scale testing. By completing water jet shaft power measurements on an Incat vessel during sea trials, comparison of these results was made to model-scale test results to provide good correlation. The work demonstrates that the International Towing Tank Conference (ITTC) extrapolation techniques used provide a good basis for extrapolating the data from model-scale to full-scale to predict the power requirements for the full-scale catamaran vessel operating at high Froude Number with water jet propulsion. This provides a useful tool for future designers and researchers for determining the power requirements of a catamaran vessel through model tests.

Computer Aided Analysis of High-Speed Single Row, Spherical Roller Bearings and Comparison With Full-Scale Test Results

1993 ◽  
Author(s):  
A. K. Aggarwal ◽  
D. M. Michaels ◽  
C. H. Keller
Keyword(s):  
Computer Program ◽  
High Speed ◽  
Mathematical Formulation ◽  
Roller Bearing ◽  
Full Scale ◽  
Full Scale Test ◽  
Operating Characteristics ◽  
Single Row ◽  
Roller Bearings ◽  
Scale Test

Abstract Single row, angular contact, spherical roller bearings were designed, analyzed, and tested to study their feasibility in a high speed (1.15 million DN) spiral bevel input pinion application. A mathematical formulation, modeling the mechanics of internal motions, load and stress distributions, lubricant flow, sliding friction, heat generation and heat transfer, was developed to analyze the bearing performance and predict operating characteristics. An interactive computer program, capable of running on a DOS PC, was then developed to solve the bearing model for the given parameters of geometry, materials, loads, and speed. The computer program, named SASHBEAN (Sikorsky Aircraft Spherical Roller High Speed Bearing ANalysis), also provided the capability of “lumped capacity” thermal analyses of the bearing and its supporting mechanical system. Six test bearings, conforming to a 216 cylindrical roller bearing OD (140 mm) and ID (80mm), were manufactured using Carpenter Pyrowear® Alloy 53 steel rings. Both conventional (with steel rollers) and hybrid (with silicon nitride rollers) configurations were built and tested under different setup conditions of loads (radial and axial), speed, and lubrication. Excellent correlation was found between the full scale test data and the computer analyses results. The analysis also provides an excellent comparison of the performance characteristics of an hybrid bearing with those of an “all steel” bearing for this high speed transmission application.

Effects of the highway live load on the additional forces of the continuously welded rails of a long-span suspension bridge

2021 ◽  
pp. 095440972110619
Author(s):  
Xiangdong Yu ◽  
Nengyu Cheng ◽  
Haiquan Jing
Keyword(s):  
High Speed ◽  
Suspension Bridge ◽  
Additional Stress ◽  
Live Load ◽  
Analysis Model ◽  
Maximum Displacement ◽  
Obvious Effect ◽  
Long Span Bridges ◽  
Long Span ◽  
Track Bridge

High-speed running trains have higher regularity requirements for rail tracks. The track-bridge interaction of long-span bridges for high-speed railways has become a key factor for engineers and researchers in the last decade. However, studies on the track-bridge interaction of long-span bridges are rare because the bridges constructed for high-speed railways are mainly short- or moderate-span bridges, and the effects of the highway live load on the additional forces of continuously welded rails (CWRs) have not been reported. In the present study, the effects of the highway live load on the additional forces of a CWR of a long-span suspension bridge are investigated through numerical simulations. A track-bridge spatial analysis model was established using the principle of the double-layer spring model and the bilinear resistance model. The additional stress and displacement of the rail are calculated, and the effects of the highway live load are analyzed and compared with those without a highway live load. The results show that the highway live load has an obvious effect on the additional forces of a CWR. Under a temperature force, the highway live load increases the maximum tensile stress and compressive stress by 10 and 13%, respectively. Under a bending force, the highway live load increases the maximum compressive rail stress and maximum displacement by 50 and 54%, respectively. Under a rail breaking force, when the highway live load is taken into consideration, the rail displacement at both sides of the broken rail varies by 50 and 42%, respectively. The highway live load must be taken into consideration when calculating the additional forces of rails on highway-railway long-span bridges.

Sign in / Sign up

Export Citation Format

Share Document