Investigation of Pantograph Effect on High-Speed Train Noise

2012 ◽  
Vol 233 ◽  
pp. 239-242
Author(s):  
Xiao Feng Zhang ◽  
You Gang Xiao ◽  
He Lian Deng ◽  
Jian Feng Huang
Keyword(s):  
High Speed ◽  
Microphone Array ◽  
Broad Band ◽  
Side Wall ◽  
Sound Field ◽  
Noise Spectrum ◽  
Low Noise ◽  
Sound Insulation ◽  
Vehicle Noise ◽  
Sealing Performance

Using microphone and removable planar microphone array, the exterior and interior vehicle noise near pantograph were investigated when the train ran at 250-350km/h, the noise spectrum characters of these areas were obtained. The results show that at the pantograph seat and in the vehicle below pantograph, the noise spectrum show a broad band distribution, and the noise energy is mainly concentrated within the range of 100Hz-2kHz. Interior vehicle noise below pantograph is a non-uniform reverberant sound field, the regions with larger sound pressure level (SPL) are distributed near the roof, the floor, the side wall below the luggage. For reducing interior vehicle noise below pantograph, such measures as using low noise pantograph, adding sound insulation pad, filling sound absorption materials and improving sealing performance should be taken, and these measures should be effective at 100Hz-2kHz.

Effect of Pantograph and Bogie on Interior Noise of High-Speed Train in Tunnel

2013 ◽  
Vol 664 ◽  
pp. 191-196
Author(s):  
You Gang Xiao ◽  
Yu Shi
Keyword(s):  
High Speed ◽  
Sound Pressure ◽  
Broad Band ◽  
Pressure Level ◽  
Channel Noise ◽  
High Speed Train ◽  
Noise Sources ◽  
Vehicle Noise ◽  
Measurement And Analysis ◽  
Analysis System

For clarifying the noise in tunnel affected by pantograph and bogie, which are the most important noise sources, the noises near pantograph and bogie in a high-speed train were tested by multi-channel noise measurement and analysis system in tunnel, and compared with those measured outside the High-speed train and on an open field. The results show that the interior vehicle noise is spatially non-homogeneous in the whole carriage, the larger sound pressure level (SPL) near pantograph are next to ceiling, and near bogie next to floor. The noise spectra show a broad band feature, and dominated by the frequency contents among 100Hz-2kHz, so the countermeasures against noise should be within these range.

Investigation of the Internal Carrier Distribution in 4H-SiC Pin-Diodes by Laser Absorption Experiments

2008 ◽  
Vol 600-603 ◽  
pp. 493-496 ◽  
Author(s):  
Dorothea Werber ◽  
Martin Aigner ◽  
D. Denoth ◽  
F. Wittmann ◽  
Gerhard Wachutka
Keyword(s):  
Charge Carrier ◽  
High Speed ◽  
Hole Concentration ◽  
Broad Band ◽  
Low Noise ◽  
Blue Laser ◽  
Charge Carrier Density ◽  
Carrier Distribution ◽  
Pin Diodes ◽  
Laser Absorption

We present an experimental equipment for studying the charge carrier distribution in the interior of bipolar 4H-SiC high power devices by means of laser absorption measurements. Since the light absorption coefficient in a semiconductor depends on the electron and hole concentration, the attenuation of a laser beam transmitted through a sample is an integral function of the local charge carrier density. In order to detect the tiny changes in the light intensity caused by the plasma-optical effect, a highly sensitive measurement set-up has been developed. Its crucial components are a low-noise blue laser and a high-speed and broad-band photo-diode amplifier circuit. Sample preparation is sophisticated and requires special care. We investigated charge carrier profiles in 4H-SiC pin-diodes in the high-injection regime at current densities between 175 A/cm² and 350 A/cm². The measured charge carrier profiles are in good agreement with computer simulations.

scholarly journals Optimization of Fixed Microphone Array in High Speed Train Noises Identification Based on Far-Field Acoustic Holography

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Rujia Wang ◽  
Shaoyi Bei
Keyword(s):  
Objective Function ◽  
Sound Source ◽  
Source Identification ◽  
High Speed ◽  
Microphone Array ◽  
Sound Field ◽  
Optimization Method ◽  
Far Field ◽  
Acoustic Holography ◽  
Sound Source Identification

Acoustical holography has been widely applied for noise sources location and sound field measurement. Performance of the microphones array directly determines the sound source recognition method. Therefore, research is very important to the performance of the microphone array, its array of applications, selection, and how to design instructive. In this paper, based on acoustic holography moving sound source identification theory, the optimization method is applied in design of the microphone array, we select the main side lobe ratio and the main lobe area as the optimization objective function and then put the optimization method use in the sound source identification based on holography, and finally we designed this paper to optimize microphone array and compare the original array of equally spaced array with optimization results; by analyzing the optimization results and objectives, we get that the array can be achieved which is optimized not only to reduce the microphone but also to change objective function results, while improving the far-field acoustic holography resolving effect. Validation experiments have showed that the optimization method is suitable for high speed trains sound source identification microphone array optimization.

Analysis of source contribution to pass-by noise for a moving high-speed train based on microphone array measurement

Measurement ◽  
2021 ◽  
Vol 174 ◽  
pp. 109058
Author(s):  
Muxiao Li ◽  
Shuoqiao Zhong ◽  
Tiesong Deng ◽  
Ziwei Zhu ◽  
Xiaozhen Sheng
Keyword(s):  
High Speed ◽  
Microphone Array ◽  
High Speed Train ◽  
Source Contribution ◽  
Array Measurement

scholarly journals Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Performance Test ◽  
High Reliability ◽  
High Vacuum ◽  
Test System ◽  
Low Noise ◽  
Speed Ratio ◽  
Space Harmonic ◽  
Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

Whitecap coverage measurements in laboratory modeling of wind-wave interaction in presence of induced wave breaking

2021 ◽  
Author(s):  
Alexander Kandaurov ◽  
Yuliya Troitskaya ◽  
Vasiliy Kazakov ◽  
Daniil Sergeev
Keyword(s):  
Wave Breaking ◽  
Water Surface ◽  
High Speed ◽  
Wind Wave ◽  
Wave Train ◽  
Side Wall ◽  
Channel Cross Section ◽  
Whitecap Coverage ◽  
Wave Channel ◽  
Manual Processing

<p>Whitecap coverage were retrieved from high-speed video recordings of the water surface obtained on the unique laboratory faculty The Large Thermostratified Test Tank with wind-wave channel (cross-section from 0.7×0.7 to 0.7×0.9 m<sup>2</sup> at the end, 12 m fetch, wind velocity up to 35 m/s, U<sub>10</sub> up to 65 m/s). The wind wave was induced using a wave generator installed at the beginning of the channel (a submerged horizontal plate, frequency 1.042 Hz, amplitude 93 mm) working in a pulsed operation (three periods). Wave breaking was induced in working area by a submerged plate (1.2×0.7 m<sup>2</sup>, up to 12 depth, AOA -11,7°). Experiments were carried out for equivalent wind velocities U<sub>10</sub> from 17.8 to 40.1 m/s. Wire wave gauge was used to control the shape and phase of the incident wave.</p><p>To obtain the surface area occupied by wave breaking, we used two Cygnet CY2MP-CL-SN cameras with 50 mm lenses. The cameras are installed above the channel at a height of 273 cm from the water surface, separated by 89 cm. The image scale was 302 μm/px, the size of the image obtained from each camera is 2048x1088 px<sup>2</sup>, which corresponds to 619x328 mm<sup>2</sup> (the long side of the frame along the channel). The shooting was carried out with a frequency of 50 Hz, an exposure time of 3 ms, 250 frames were recorded for each wave train. To illuminate the image areas to the side of the measurement area, a diffuse screen was placed on the side wall, which was illuminated by powerful LED lamps to create a uniform illumination source covering the entire side wall of the section.</p><p>Using specially developed software for automatic detection of areas of wave breaking, the values of the whitecap coverage area were obtained. Automatic image processing was performed using morphological analysis in combination with manual processing of part of the frames for tweaking the algorithm parameters: for each mode, manual processing of several frames was performed, based on the results of which automatic algorithm parameters were selected to ensure that the resulting whitecap coverage corresponded. Comparison of images obtained from different angles made it possible to detect and exclude areas of glare on the surface from the whitecap coverage.</p><p>The repeatability of the created wave breakings allows carrying out independent measurements for the same conditions, for example the parameters of spray generation will give estimations of the average number of fragmentation events per unit area of the wave breaking area.</p><p>The work was supported by the RFBR grants 21-55-50005 and 20-05-00322 (conducting an experiment), President grant for young scientists МК-5503.2021.1.5 (software development) and the RSF grant No. 19-17-00209 (data processing).</p>

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