Comparison on General Track Spectrum for Chinese Main Railway Lines and Track Spectrum of American Railway Lines

2011 ◽  
Vol 250-253 ◽  
pp. 3822-3826 ◽  
Author(s):  
Xian Mai Chen ◽  
Xia Xin Tao ◽  
Gao Hang Cui ◽  
Fu Tong Wang
Keyword(s):  
Dynamic Performance ◽  
Dynamic Responses ◽  
Wave Band ◽  
Wheel Load ◽  
Railway Line ◽  
Acceleration Rate ◽  
Time Histories ◽  
Railway System ◽  
Dynamic Performances ◽  
Track Irregularity

The general track spectrum of Chinese main railway lines (ChinaRLS) and the track spectrum of American railway lines (AmericaRLS) are compared in terms of character of frequency domain, statistical property of time domain samples and dynamic performance. That the wavelength range of the ChinaRLS, which is characterized by the three levels according to the class of railway line, is less than AmericaRLS at common wave band of 1~50m is calculated. Simultaneously, the mean square values of two kinds of track spectra are provided at the detrimental wave bands of 5~10m, 10~20m, and so on. The time-histories of ChinaRLS and AmericaRLS are simulated according to the trigonometric method, and the digital statistical nature of simulated time samples is analyzed. With inputting the two kinds of time-histories into the vehicle-railway system, the comparative analysis of the two kinds of dynamic performances for ChinaRLS and AmericaRLS is done in terms of car body acceleration, rate of wheel load reduction, wheel/rail force, and the dynamic responses of track structure. The result shows that ChinaRLS can characterize the feature of the Chinese track irregularity better than AmericaRLS, the track irregularity with the ChinaRLS of 200km/h is superior to the AmericaRLS, and the track irregularity with the ChinaRLS of 160km/h corresponds to with the sixth of AmericaRLS.

Effect of Track Geometric Irregularity on Dynamic Characteristics of Gear Transmission in a Locomotive

2017 ◽  
Author(s):  
Tao Zhang ◽  
Zaigang Chen ◽  
Jie Zhang ◽  
Shunqi Sui ◽  
Cheng Pan
Keyword(s):  
Dynamic Characteristics ◽  
Life Prediction ◽  
Dynamic Performance ◽  
Gear Transmission ◽  
Fatigue Life Prediction ◽  
Dynamic Responses ◽  
Mean Square ◽  
Track Irregularity ◽  
Working Performance ◽  
Statistical Indicators

Gear transmission is a key component in locomotive where it delivers the traction or braking forces between the motor and the wheelset. Its working performance has a direct effect on the operating reliability and safety. Therefore, investigation on the dynamic characteristics of the gear transmission in locomotives is very meaningful. In this study, a gear transmission-locomotive-track spatial coupled dynamic model is established based on the classical locomotive-track coupled dynamics and the gear dynamics theory. Based on this model, the dynamic responses of the gear transmission can be analysed under excitations from different track geometrical irregularity, and the dynamic performance of the gear transmission can be obtained. This paper also studies the effect law of the track irregularity on the vibration of the gear transmission by using statistical indicators RMS (Root Mean Square) and PtP (Peak-to-Peak). The results indicate that the track geometrical irregularity has an obvious impact to the dynamic performance of gear transmission. The dynamic response of the gear transmission will increase violently when the locomotive runs on the track in a worse condition. The results are expected to be capable of providing some references for fatigue life prediction and reliability analysis of the gear transmissions in locomotive.

Dynamic Performance of Vehicle-Turnout-Bridge Coupling System in High-Speed Railway

2011 ◽  
Vol 50-51 ◽  
pp. 654-658
Author(s):  
Rong Chen ◽  
Wang Ping ◽  
Shun Xi Quan
Keyword(s):  
Relative Position ◽  
High Speed ◽  
Dynamic Performance ◽  
Dynamic Responses ◽  
Continuous Beam ◽  
Analysis Model ◽  
Wheel Load ◽  
System A ◽  
Coupling System ◽  
Contact Relation

In order to study dynamic behavior of vehicle-turnout-bridge coupling system, a vehicle-turnout-bridge dynamic analysis model is established by employing the dynamic finite element method (FEM). When No.18 crossover turnouts(with a speed of 350km/h) are laid symmetrically on the 6×32m continuous beam, influences of turnout/bridge relative position and wheel/rail contact relation in turnout zone on the system dynamic responses are analyzed. The result shows that: wheel/rail contact of turnout zone (especially the frog) has great effect on dynamic responses of turnout on bridge, thus the nose rail height of frog should be optimized to mitigate the wheel load transition and its longitudinal gradient. In terms of the 32m-span continuous beam, the best relative position is frog part of turnout arranged in the range of 1/8 and 1/4 of span.

scholarly journals Dynamic Wheel-Rail Force-Based Track-Irregularity Evaluation for Ballasted Track on Serviced Railway by Adjacent Excavation

2021 ◽  
Vol 12 (1) ◽  
pp. 375
Author(s):  
Jung-Youl Choi ◽  
Dong-Ryong Park ◽  
Jee-Seung Chung ◽  
Sun-Hee Kim
Keyword(s):  
Impact Load ◽  
Field Measurements ◽  
Interaction Force ◽  
Wheel Load ◽  
Track Geometry ◽  
Railway Line ◽  
Before And After ◽  
Track Irregularity ◽  
The Impact ◽  
Track Irregularities

This study investigates a load-based, track-irregularity-analysis technique for ballasted tracks on a serviced railway line with respect to excavation work conducted in adjacent sites. A numerical analysis and field measurements (railbed-settlement-monitoring sensor, track-geometry-measurement system, wheel-load measurements) were analyzed comparatively to demonstrate the correlation between the track irregularities and the Wheel-Rail interaction force. In this way, we highlight the necessity for load-based track-irregularity-management methods. The analyzed results show that the maximum dynamic wheel load was measured in the range of approximately 10 m before and after the location where the maximum track irregularities occurred, and that even if the maintenance criteria of track irregularities were satisfied, the design dynamic wheel load could still be exceeded depending on the train speed, thus indicating that track damage can be caused by the impact load.

Experimental Study on the Dynamic Performance of Long-Span Steel Arch Bridge in Passenger Dedicated Line

2012 ◽  
Vol 490-495 ◽  
pp. 2347-2351
Author(s):  
Xian Feng Wei ◽  
Jian Qing Bu ◽  
Jian Guo Chen
Keyword(s):  
Dynamic Performance ◽  
Dynamic Responses ◽  
Security Requirements ◽  
Arch Bridge ◽  
Vertical Stiffness ◽  
Box Section ◽  
Long Span ◽  
Dynamic Performances ◽  
Tied Arch Bridge ◽  
Passenger Dedicated Line

By the experiment on dynamic performance of long-span steel arch bridge, the natural frequency and dynamic responses of the 140m steel box-section tied arch bridge over the Ting Si River Bridge in the Wuhan-Guangzhou Passenger Dedicated Line are tested. the tested results of the bridge dynamic responses show that the bridge structure can meet the security requirements when CRH2 EMU runs on it in the speed of 250 to 350km/h.the lateral and vertical stiffness are larger, the vertical and lateral natural frequencies and the other dynamic performances of the bridge can meet the requirements of the relevant norms, When the CRH2 EMU runs across the steel box-section arch bridge in different speeds

Micro-pressure sensor dynamic performance analysis

Sensor Review ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 367-373 ◽  
Author(s):  
Bian Tian ◽  
Yulong Zhao ◽  
Zhe Niu ◽  
Jiang Zhuangde
Keyword(s):  
Dynamic Characteristics ◽  
Pressure Sensor ◽  
Dynamic Pressure ◽  
Dynamic Performance ◽  
Pressure Sensors ◽  
Dynamic Responses ◽  
Content Type ◽  
Dynamic Performances ◽  
Traditional Structures ◽  
Dynamic Performance Analysis

Purpose – The purpose of this paper is to report on a piezoresistive pressure sensor for micro-pressure measurement with a cross-beam membrane (CBM) structure. This study analyzes the dynamic characteristics of the proposed device. Design/methodology/approach – This CBM sensor possesses high stiffness and sensitivity, measuring dynamic pressure more effectively in a high-frequency environment compared with other piezoresistive structures. The dynamic characteristics are derived using the finite element method to analyze the dynamic responses of the new structure, including natural frequency and lateral effect performances. The CBM dynamic performances are compared with traditional structures. Findings – The pressure sensor performance was evaluated, and the experimental results indicate that they all exhibit similar dynamic characteristics as the designed model. Compared with traditional structures such as the single island, the CBM proves to be superior in evaluating the dynamic performances of pressure sensors at high frequencies of > 30 kHz. Originality/value – Most studies of this micro pressure sensors attempt to promote the sensitivity or focus on the static performance of pressure sensor with micro gauge. This study is concerned with analyze the dynamic characterism of micro pressure sensor and compared with the traditional structures, that prove the CBM structure has stable dynamic performance and is a better option for measuring dynamic micro pressure in biomedical applications.

scholarly journals Vibrations Induced by Mechanical Rock Excavation on R.C. Buildings in an Urban Area

Buildings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Valeria Leggieri ◽  
Annamaria di Lernia ◽  
Gaetano Elia ◽  
Domenico Raffaele ◽  
Giuseppina Uva
Keyword(s):  
Urban Area ◽  
Dynamic Performance ◽  
Numerical Approach ◽  
Fe Model ◽  
Railway Line ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Input Motion ◽  
Impulse Force ◽  
Construction Works

The paper describes the numerical approach adopted to investigate the effects of vibrations induced on reinforced concrete (R.C.) buildings by the excavation works needed to bury an existing railway line crossing an urban area in the south of Italy. The construction works are carried out in dolomitic rocks, characterized by a high resistance to excavation. Therefore, they may have a great impact on the surrounding environment in terms of induced vibrations. The study is conducted through an uncoupled approach, investigating the dynamic response of the geotechnical system and the above-surface structure, separately. The impulse force equivalent to the dynamic action of a breaker hammer is used as input motion for 2D finite element (FE) geotechnical simulations of the wave propagation process occurring during the excavation. Then, the acceleration time histories obtained from the geotechnical analyses are adopted to study the dynamic performance of an “index” R.C. building, representing the most recurrent structural typology in the examined area, through a 3D FE model. The results show how the adoption of a mitigation strategy consisting in the execution of a preliminary vertical cut followed by a rock crushing treatment allows to significantly reduce the vibrations induced by the excavation processes on existing buildings.

Evaluation for Dynamic Performance of Simple-Continuous Bridge

2011 ◽  
Vol 250-253 ◽  
pp. 1360-1365
Author(s):  
Ke Jian Sheng ◽  
Zong Lin Wang
Keyword(s):  
Vibration Amplitude ◽  
Dynamic Performance ◽  
Influential Factors ◽  
Dynamic Responses ◽  
Coupled Vibration ◽  
Vehicle Model ◽  
Structural Dynamic ◽  
Standard Design ◽  
Dynamic Performances ◽  
Traveling Speed

It is necessary to study the dynamic responses of simple-continuous bridges under traveling vehicles action, which may benefit the improvement of their dynamic performances. According to “Standard Design Drawings” issued by Ministry of Communications of PRC, this paper considers the alterations of span length, decking width and sectional style and the differences of vehicle model and traveling speed, and calculates separately dynamic response of these structures with the “vehicle-bridge coupled vibration program”. As two key influential factors, vibration amplitude and acceleration are applied for the evaluation of structural dynamic performance. The results show that dynamic performance of simple-continuous cored slab bridge is deficiency in some degree.

Influencing Factors of Dynamic Performance of Jointless Turnout on Bridge in High-Speed Railway

2010 ◽  
Author(s):  
R. Chen ◽  
P. Wang ◽  
X. P. Chen
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Dynamic Responses ◽  
Wheel Load ◽  
Longitudinal Gradient ◽  
High Speed Railway ◽  
Coupling Vibration ◽  
Vertical Stiffness ◽  
Coupling System ◽  
Chinese Standard

Taking the case of 18# turnout (350km/h) laid on 6×32m continuous girder, a dynamic model for coupling system of vehicle and jointless turnout on bridge was established to analyze the factors that affected dynamic performance of jointless turnout on bridge, and several aspects were taken into consideration, i.e. train’s running quality, rail stress of turnout, vibration of turnout and bridge, and deformation, etc. It is shown that influenced by vibration and deformation of bridge, the train, turnout and bridge form a coupling vibration system, whose dynamic responses are stronger than those caused by train/turnout interaction on subgrade. Wheel/rail contact of turnout zone (especially the frog) has great effect on dynamic responses of jointless turnout on bridge, thus the nose rail height of frog should be optimized to mitigate the wheel load transition and its longitudinal gradient. When a train is passing a jointless turnout on bridge, a reasonable vertical stiffness for bridge is the key to keep its safety and comfort; as for the 32m continuous girder, the ratio of deflection to span should be ≤1/9000 under the ZK load (Chinese standard).

Influences of Wind Barriers on the Train Running Safety on a Highway-Railway One-Story Bridge

2021 ◽  
pp. 2140009
Author(s):  
Ye Liu ◽  
Yan Han ◽  
Peng Hu ◽  
C. S. Cai ◽  
Xuhui He
Keyword(s):  
Dynamic Responses ◽  
Response Analysis ◽  
Train Track ◽  
Wheel Load ◽  
Wind Barrier ◽  
The Mean ◽  
Wind Pressures ◽  
Track Bridge ◽  
Fluctuating Wind ◽  
Bridge System

In this study, the influences of wind barriers on the aerodynamic characteristics of trains (e.g. a CRH2 train) on a highway-railway one-story bridge were investigated by using wind pressure measurement tests, and a reduction factor of overturning moment coefficients was analyzed for trains under wind barriers. Subsequently, based on a joint simulation employing SIMPACK and ANSYS, a wind–train–track–bridge system coupled vibration model was established, and the safety and comfort indexes of trains on the bridge were studied under different wind barrier parameters. The results show that the mean wind pressures and fluctuating wind pressures on the trains’ surface decrease generally if wind barriers are used. As a result, the dynamic responses of the trains also decrease in the whole process of crossing the bridge. Of particular note, the rate of the wheel load reductions and lateral wheel-axle forces can change from unsafe states to relative safe states due to the wind barriers. The influence of the porosity of the wind barriers on the mean wind pressures and fluctuating wind pressures on the windward sides and near the top corner surfaces of the trains are significantly greater than the influence from the height of the wind barriers. Within a certain range, decreasing the wind barrier porosities and increasing the wind barrier heights will significantly reduce the safety and comfort index values of trains on the bridge. It is found that when the porosity of the wind barrier is 40%, the optimal height of the wind barrier is determined as approximately 3.5[Formula: see text]m. At this height, the trains on the bridges are safer and run more smoothly and comfortably. Besides, through the dynamic response analysis of the wind–train–track–bridge system, it is found that the installation of wind barriers in cases with high wind speeds (30[Formula: see text]m/s) may have an adverse effect on the vertical vibration of the train–track–bridge system.

Dynamic Performance Analysis on High-Speed Railway Continuous Girder Bridge

2011 ◽  
Vol 280 ◽  
pp. 186-190
Author(s):  
Shou Tan Song ◽  
Ji Wen Zhang ◽  
Xin Yuan
Keyword(s):  
High Speed ◽  
Moving Load ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Wheel Load ◽  
Dynamic Coefficients ◽  
Bridge Structures ◽  
Continuous Girder Bridge ◽  
Girder Bridge ◽  
Dynamic Performance Analysis

The dynamic performance of continuous girder under the train in a series of speed is studied through examples, and the main conclusions are given in the following. The resonance mechanism of continuous girder is similar to simply supported beam. The vehicle wheel load forms regular moving load series, which induces periodical action and resonance of the bridge. The damping ratio of bridge itself has less effect on the amplitude at the loading stage, but significant effects appear when the load departs from the bridge. The count of continuous spans also has less impact on the dynamic coefficients, so three continuous spans can be adopted for calculation and analysis. Span and fundamental frequency have significant influence on dynamic coefficients of bridge structures. To extend the span of the bridge structure can reduce the dynamic coefficient while keeping its frequency invariant. The fundamental frequencies of different bridges are corresponding to certain resonant speeds, which calls for the attention in the design.

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