scholarly journals Fatigue Performance of the CA Mortar Used in CRTS I Ballastless Slab Track under Simulated Servicing Condition

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2259 ◽  
Author(s):  
Yuchuan Shan ◽  
Shuguang Zheng ◽  
Xuefeng Zhang ◽  
Wei Luo ◽  
Jingda Mao ◽  
...  
Keyword(s):  
Fatigue Test ◽  
High Frequency ◽  
High Speed ◽  
Comfort Level ◽  
Polymer Emulsion ◽  
High Speed Railway ◽  
High Frequency Vibration ◽  
Vibration Load ◽  
Slab Track ◽  
Ca Mortar

The cement and asphalt mortar (CA mortar) used in the China Railway Track System (CRTS) I ballastless slab track may encounter a coupling fatigue effect under the high-frequency vibration, load and high-and-low temperature cycles, and the deterioration under fatigue may happen during service of the high-speed railway. In this study, the performance degradation and its mechanism of the CA mortar with and without polymer emulsion incorporated under the coupling fatigue effects of the high-frequency vibration, load and temperature were studied by using an anti-fatigue testing device specially developed for the CA mortar used in the ballastless slab track of the high-speed railway. The results showed that the deformation capacity of the CA mortar for CRTS I slab ballastless slab track decreased after fatigue test under simulated service environment, presenting a typical brittle characteristic and an obvious reduction of the ductility and toughness. The Scanning Electron Microscopy (SEM) observation and the mercury intrusion porosimetry (MIP) analysis showed that the volume of the macropore decreased whereas that of the micropore increased after the fatigue test. The asphalt in the hardened CA mortar revealed a softening and migration from the bulk paste to fill the pore and make the structure denser and even ooze out of the CA mortar under the high-frequency vibration and high temperature. Through incorporating the polymer emulsion, the anti-fatigue property of the CA mortar was obviously improved, which can prevent the CA mortar from losing its elastic adjustment function too early. Though increase of the strength and elastic modulus for the CA mortar after severe service is beneficial to the stability of train running, the comfort level and safety of the train operation may decline due to the gradual reduction of the ductility & toughness and the gradual loss of the elastic damping adjustment function of the CA mortar between the base concrete slab and the track slab.

Research and Progress on CA Mortar Emulsifying Asphalt of Ballast-Less Slab Track

2011 ◽  
Vol 239-242 ◽  
pp. 2399-2402 ◽  
Author(s):  
Ming Chao Qi ◽  
Xiao Xuan Li ◽  
Zhong Qi Jia
Keyword(s):  
Primary Structure ◽  
High Speed ◽  
Track Structure ◽  
Structure Form ◽  
High Speed Railway ◽  
Slab Track ◽  
Ca Mortar

Ballast-less slab track is the primary structure form of the modern high-speed railway, and cements phalt mortar is the most important component of flexible adjusting layer of slab track structure. This article introduces simply development and application of ballast-less track，then detailed explain the production and research of cements phalt mortar special asphalt lotion .

scholarly journals 1212 Analysis on High Frequency Vibration Characteristic of Passenger-Seat in High Speed Railway Vehicle

2011 ◽  
Vol 2011.20 (0) ◽  
pp. 111-114
Author(s):  
Sotaro SAITO ◽  
Ryuzo HAYASHI ◽  
Masao NAGAI ◽  
Ryohei SHIMAMUNE ◽  
Masahiko MIZUGUCHI ◽  
...  
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Railway Vehicle ◽  
Vibration Characteristic ◽  
High Speed Railway ◽  
High Frequency Vibration ◽  
Passenger Seat

scholarly journals Research into Correlation between the Lubrication Mode of Contact Surfaces and Dynamic Parameters of Turbo-Generator Transmissions

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Marek Kočiško ◽  
Petr Baron ◽  
Monika Telíšková ◽  
Jozef Török ◽  
Anna Bašistová
Keyword(s):  
Acoustic Emission ◽  
High Frequency ◽  
High Speed ◽  
Oil Quality ◽  
The State ◽  
Dynamic Parameters ◽  
High Frequency Vibration ◽  
Turbo Generator ◽  
Friction Mode ◽  
Contact Surfaces

The paper presents the results of an experimental study aimed at assessing the correlation between the measurement of dynamic parameters (vibration, high-frequency vibration, and acoustic emission) and the analysis of friction mode and the state of lubrication of the contact surfaces of two gearboxes in the turbo-generator assembly (high-speed single-body steam turbine—gearbox—generator) with the transmission power of no more than 50 MW. The analysis confirmed the assumption of a significant correlation of the monitored high-frequency vibration signal with the unsatisfactory engagement of the gear teeth. Through vibration analysis, an increased level of the tooth vibration component and vibration multiples with increased acoustic emission were identified in gearbox operation. The gear oil of one of the gearboxes examined showed a loss of additive elements in the real operation of the contact surfaces of the teeth engagement. The trend analysis confirmed the complexity of the monitored transmission operation in terms of the friction mode and the influence of the oil quality on the state of the tooth flank microgeometry.

scholarly journals An Ultra-High Frequency Vibration-Based Fatigue Test and Its Comparative Study of a Titanium Alloy in the VHCF Regime

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1415
Author(s):  
Wei Xu ◽  
Yanguang Zhao ◽  
Xin Chen ◽  
Bin Zhong ◽  
Huichen Yu ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Fatigue Test ◽  
High Frequency ◽  
High Efficiency ◽  
Fatigue Tests ◽  
Loading Frequency ◽  
Fatigue Specimen ◽  
Ultra High Frequency ◽  
High Frequency Vibration ◽  
Testing Data

This paper proposes an ultra-high frequency (UHF) fatigue test of a titanium alloy TA11 based on electrodynamic shaker in order to develop a feasible testing method in the VHCF regime. Firstly, a type of UHF fatigue specimen is designed to make its actual testing frequency reach as high as 1756 Hz. Then the influences of the loading frequency and loading types on the testing results are considered separately, and a series of comparative fatigue tests are hence conducted. The results show the testing data from the present UHF fatigue specimen agree well with those from the conventional vibration fatigue specimen with the loading frequency of 240 Hz. Furthermore, the present UHF testing data show good consistency with those from the axial-loading fatigue and rotating bending fatigue tests. But the obtained fatigue life from ultrasonic fatigue test with the loading frequency of 20 kHz is significantly higher than all other fatigue test results. Thus the proposed ultra-high frequency vibration-based fatigue test shows a balance of high efficiency and similarity with the conventional testing results.

Key Issues on Train Line Planning for Beijing-Shanghai High Speed Railway

2010 ◽  
Author(s):  
L. Nie ◽  
D. B. Fei ◽  
S. D. Zhou ◽  
H. L. Fu ◽  
L. Tong
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Travel Demand ◽  
Time Window ◽  
Long Distance ◽  
Line Planning ◽  
High Speed Railway ◽  
Passenger Flow ◽  
Train Operation ◽  
Service Plan

The Beijing-Shanghai High speed railway line (Hereinafter referred to as “Jing-Hu HSL”) is one of the most important railway lines in the Chinese rapid passenger transportation network and will be put into operation at the end of 2011. Train line planning directly reflects the quality and competition ability of train services. The characteristics of operational conditions and passenger flow of this corridor HSL bring about a few new issues on train line planning like night train operation, train OD sets, cyclic operation, and train stop schedule. For the first issue, a large amount of long distance travel demand put forward the demand for night services, which causes great conflict with the time-window for maintenance work. The confliction can be solved by harmoniously utilizing the parallel lines. For the second one, in view of the differences of technical and economic factors between HSL and conventional railways, high frequency and medium-long distance train will dominate HSL’s train service plan rather than low frequency and long distance trains on conventional railways. Thus, part of long-distance passenger flow has to transfer at some stations. Considering the whole possible ODs over Jing-Hu HSL and the transfer condition of related stations, the optimal OD sets and corresponding transfer plan is suggested. High frequency makes HSL possible to operate trains cyclically to improve service quality. However, with too many train ODs and some special trains, e.g. night train, an incomplete cyclic train operation mode is more practical. The ODs which can provide cyclic service for Jing-Hu HSL need to be identified. For the last issue, although non-stop long-distance train is a very popular kind of service in China, it should be reconsidered for Jing-Hu HSL line because of massive intercity travel demand and regular stops required. Each of the above issues is very complex. What is more, they have close relationship between each other. Due to limited space, the methods used to solve these issues are given in conceptual way rather than detailed description of mathematical model. The research paves the way for future integration study to design an efficient, economic, convenient, and regular train service plan for Jing-Hu HSL.

scholarly journals Structural Improvement of the ω-Type High-Speed Rail Clip Based on a Study of Its Failure Mechanism

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Xiaogang Gao ◽  
Anbin Wang ◽  
Yu He ◽  
Xiaohan Gu
Keyword(s):  
Failure Mechanism ◽  
Fatigue Test ◽  
High Frequency ◽  
High Speed ◽  
Excitation Frequency ◽  
Test System ◽  
Vibration Measurement ◽  
High Speed Rail ◽  
Resonant Frequencies ◽  
Rail Wear

In the circumstances of high-speed railways, the wheel-rail vibration is significantly aggravated by polygonal wheel wear and rail corrugation, which subsequently leads to the wheel-rail interaction at higher frequencies and potential failure of the rail fastening. In this paper, a ω-type clip of the fastening in the CRH high-speed rail was used to investigate the failure mechanism. First, a dynamic wheel-rail coupling model and a finite element analysis of the rail clip were developed, from which the rail vibration frequency and modal frequencies of the clip with different installation torques were obtained. The experimental tests and modal simulation results were mutually verified. In addition, the real-time vibration measurement and the wheel-rail wear monitoring were carried out at a CRH high-speed railway site. It was found that the resonant frequencies of the ω-type clip in the installation condition coincided with the excitation frequencies of the wheel-rail interaction induced by wheel-rail wear. The high-frequency dynamic failure mechanism of a typical ω-type clip, W300-1, is put forward for the first time. Moreover, a high-frequency rail clip fatigue test system was designed and developed specifically for this study. The loading excitation frequency of the clip test used was set as 590 Hz, and the loading amplitude was 0.05 mm. After 125-minute operation of the test system, the clip was broken at the expected location predicted by the FEA model. The high-frequency fatigue test result further verified that the failure mechanism of the ω-type clip was due to the resonance of the clip with its excitation force from the wheel-rail interaction. Finally, the clip was then structurally improved taking into account the stiffness and mass, which led to its resonant frequencies shifting away from the high-frequency excitation range, hence avoiding resonance failure of the subject clip.

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