This standard specifies the measurement method of radiated noise of railway locomotives and rolling stock. This standard applies to the measurement of radiated noise of railway locomotives and rolling stock during type inspection and supervisory inspection. GB/T 5111-1995 Acoustics Measurement of radiated noise of railway locomotives and rolling stock GB/T5111-1995 Standard download decompression password: www.bzxz.net
This standard specifies the measurement method of radiated noise of railway locomotives and rolling stock. This standard applies to the measurement of radiated noise of railway locomotives and rolling stock during type inspection and supervisory inspection.

National Standard of the People's Republic of China
Measurement of noise emitted by railbound vehicles
Acoustics--Measurement of noise emitted by railbound vehicles
1 Subject content and scope of application
This standard specifies the measurement method of noise emitted by railbound vehicles. This standard applies to the measurement of noise emitted by railbound vehicles during type inspection and supervisory inspection. 2 Referenced standards
GB3785 Electrical and acoustic properties and test methods of sound level meters GB3241 1/1 and 1/3 octave filters for sound and vibration analysis JJG699 Verification procedures for integrating sound level meters
3 Terminology
3.1 Noise emitted by railbound vehicles Noise radiated outward from the noise source of a locomotive or vehicle using air as the medium. 3.2 Background noise of railway Noise at the measuring point when the locomotive or vehicle under inspection is not on site during the entire measurement time. 4 Basic technical requirements
GB/T 5111---1995
Replaces 5111-85
The measurement conditions of radiated noise for type inspection shall fully comply with the requirements of this standard. The measurement conditions for supervisory inspection may differ slightly from those specified in this standard. Any differences shall be noted in the inspection report. 5 Measuring instruments
5.1 All electroacoustic properties of measuring instruments shall be verified by the acoustic metrology department. Before and after each measurement, a sound calibrator with an accuracy equal to or better than ±0.5dB shall be used for calibration. The difference between the two calibrations shall not exceed 1dB. 5.2 Sound level meters or integrating sound level meters shall comply with the relevant provisions of GB3785 on type 1 instruments and JJG699. Filters for spectrum analysis shall comply with the provisions of GB3241.
5.3 Sound level meters and sound calibrators shall be calibrated regularly by the metrology department. The maximum calibration period shall not exceed 1 year. 5.4 When measuring, a suitable windshield should be used to reduce the influence of wind on the reading. 6 Measured quantities
6.1 All measured values ​​of the sound level meter are the "fast gear" A-weighted sound pressure level (LpAr), in dBA. 6.2 The measured value of the spectrum analysis is the octave band sound pressure level or the 1/3 octave band sound pressure level (L,), in dB. Approved by the State Administration of Technical Supervision on July 3, 1995 104
Implemented on February 1, 1996
7 Acoustic environment, meteorological conditions, background noise GB/T 5111--1995
7.1 The measurement site should be an open area with a basically flat ground. There should be no large sound reflectors (such as obstacles, hills, stones, bridges or buildings, etc.) around the microphone within three times the measurement distance. There should be no obstacles that interfere with the sound field near the microphone, and no people between the microphone and the noise source; the observer should be in a position that does not affect the reading of the sound level meter. 7.2 There should be no sound absorbing covering (such as cultivated land, grassland, etc.) between the microphone and the locomotive and vehicle being measured. 7.3 Measurement cannot be performed under the following conditions:
Cold weather with frozen ballast;
b. Snow on the ground;||t t||c When it is raining or snowing;
d. The wind speed at 2m above the rail surface exceeds 8m/s. 7.4 Railway background noise (such as other locomotives and vehicles, factory noise or wind noise, etc.) should be at least 10dBA lower than the noise of the locomotive and vehicle being tested. During spectrum analysis, the above differences in each frequency band should also meet the requirements of this article. 8 Line conditions
8.1 The line in the constant speed measurement section should meet the following requirements: a. It should be paved with gravel ballast and sleepers, and the minimum thickness of the slag under the sleepers should be 0.15m, and the slag should be flush with the sleepers; b. The track should be a continuous welded track, and the track surface should be at least 1.0m above the ground at the measurement site, and there should be no scratches, peeling, or falling blocks, etc. Abnormal defects;
c. When the speed is less than 120km/h, the track curve radius should not be less than 3000m, and when the speed is equal to or higher than 120km/h, the track curve radius should not be less than 5000m;
d. The maximum line slope should not exceed 10%. 8.2 The locomotive and rolling stock for fixed-position measurement should be parked on the track paved with sleepers and gravel ballast, and the track surface should be at least 0.5m above the ground at the measurement site.
9 Rolling stock conditions
9.1 General requirements
9.1.1 The power unit should be in normal operating condition and comply with the manufacturer's regulations. 9.1.2 Rolling stock Except for crew members, no cargo or people can be carried. The power vehicle should be of normal working quality. 9.1.3 All doors and windows should be closed at all times during measurement. If required under normal working conditions, the fan exhaust device must be fully opened. 9.2 Constant speed measurement
9.2.1 Before measurement, the locomotive vehicle should have run for at least 1000km and been subjected to multiple routine braking to ensure that the wheels and rails meet normal good running-in conditions. The wheels should avoid sliding and scratching the tread. This situation should be described in the inspection report. 9.2.2 The test train length of non-powered freight cars and passenger cars should be at least three times the measurement distance. 9.2.3 The locomotive can be measured alone without any vehicles attached. 9.2.4 If the noise of auxiliary equipment that is automatically turned on when the locomotive and vehicle are running has a significant impact on the measured value (A-weighted sound pressure level or octave band and 1/3 octave band sound pressure level) at the microphone position, it should be measured under the turned-on condition; but if it only appears occasionally or the appearance time does not exceed 1 minute, or the impact on the noise level and the sound pressure level of each octave band is less than 5dB, it can be ignored. 9.2.5 In the measurement section, the test locomotive and vehicle should be driven at the following specified speeds (the error does not exceed ±5%): a. 95% of the maximum speed of the locomotive and vehicle, but not exceeding the maximum allowable speed of the test line; b. Passenger locomotives and passenger cars at a speed of 90km/h; freight locomotives and freight cars at a speed of 70km/h; c. Trains with a speed greater than 150km/h and less than 200km/h at a speed of 150km/h. If it cannot be achieved, it should be measured at a speed reduced by 20km/h.
9.3 Fixed-position measurement
GB/T 5111—1995
9.3.1 All devices that can be started when electric locomotives and passenger cars are parked should be measured under the running condition; auxiliary equipment that is normally parked and running should be measured under the maximum load.
9.3.2 Diesel locomotives are measured under the following working conditions: diesel engine is unloaded and at the lowest speed, the fan is at the minimum speed, the auxiliary equipment is at the corresponding load, and the compressor is fully loaded. a.
The diesel engine is at the highest speed, the fan is at the highest speed, the auxiliary equipment is rated load, and the compressor is fully loaded. b.
Non-powered passenger cars or freight cars equipped with air conditioning or refrigeration systems, which can be operated when parked, should be measured under the maximum load specified by the manufacturer. 9.3.3
|||10 Microphone position
The microphone should be pointed vertically to the vertical plane passing through the center line of the track. 10.1 For constant speed measurement, the microphone shall be placed 25m from the vertical plane of the track centerline and 3.5±0.2m from the track surface. 10.2 For fixed-position measurement, the microphone shall be placed on both sides of the locomotive vehicle at a distance of 7.5m from the vertical plane of the track centerline and 3.5±0.2m from the track surface, and symmetrical to the center axis of the locomotive vehicle (see Appendix A for details). 11 Measurement method
11.1 Constant speed measurement
11.7.1 The maximum A sound level LpaF.max when the locomotive vehicle passes by shall be measured at least three times. If the maximum difference is greater than 2dB, the measurement shall continue until the difference is less than or equal to 2dB. The arithmetic average of the two maximum values ​​that meet the above requirements shall be taken as the maximum noise level of the locomotive vehicle under inspection.
11.1.2 If there is obvious pure tone or impulse noise, it shall be stated in the inspection report. 11.2 Fixed-position measurement
11.2.7 Read the "fast" A-level sound level at each measuring point, and take its arithmetic mean as the measurement result for type inspection. 11.2.2 If the sound level fluctuation is greater than 3dB, the equivalent continuous A-level sound level for at least 10s or more than one fluctuation cycle should be measured, and the arithmetic mean of the equivalent continuous A-level sound level at each microphone position shall be taken as the measurement result for type inspection. 11.2.3 If there is obvious pure tone or impulse noise, it should be stated in the inspection report. 12 Inspection report
The inspection report should include the following contents:
Nature of inspection;
Test site, track conditions and track running-in process of constant speed measurement; Measuring instruments;
Background noise level:
Locomotive and rolling stock, engine and its test speed, running-in process of constant speed measurement locomotive and rolling stock, auxiliary equipment and its operating conditions;
Locomotive and rolling stock load;
Microphone position;Www.bzxZ.net
"Fast gear A sound level, maximum A sound level; equivalent A sound level at time T and its average value; Noise spectrum measurement;
Presence of pure tone and impulse noise;
Measurement date and measurer.
A1 Microphone position
GB/T 5111—1995
Appendix A
Microphone positions for fixed rolling stock measurements (supplement)
The microphone should be placed 7.5m from the vertical plane passing through the center line of the track and should be on the outer perimeter of the vehicle as shown in Figure A1. The microphone spacing α parallel to the side of the rolling stock should be between 3 and 5m, so that three microphone positions can be obtained on each side. When the vehicle body length exceeds 20m, in addition to the six microphone positions at the front and rear of the vehicle, there will be more than six microphone positions parallel to the sides of the vehicle. The microphone positions should include the positions of the driver's cab and the lateral center of the diesel engine. Microphone It should be placed at 3.5 ± 0.2m above the track surface. When the main sound source appears at the bottom of the locomotive vehicle being inspected, it is recommended that the microphone be located between 1.2 and 1.5m above the track surface.
The microphone should be perpendicular to the outer plane of the vehicle. If you want to measure the sound level of the air intake or exhaust port of the engine, air conditioner and cooling system, it is recommended to place the microphone outside the airflow, 1m away from the inlet or outlet, at an angle of 30° to the airflow direction (see Figure A2), and as far away from the reflective surface as possible. Figure A1 Positions of measuring points around fixed locomotive vehicles 107
A2 Locomotive vehicle conditions
GB/T 51111995
Figure A2 Microphone positions at the air intake or exhaust port 1-Measurement microphone 2-Intake or exhaust pipe; 3-Airflow The rolling stock conditions shall comply with the provisions of 9.3. If the throttle valve of the no-load engine is fully opened, the short-term strong noise that occurs before the normal operation of the engine shall be recorded separately.
The fan noise shall be evaluated at the minimum and maximum speeds, and if possible, the intermediate speed may also be selected. Additional remarks:
This standard is proposed and coordinated by the National Technical Committee for Acoustic Standardization. This standard is drafted by the Institute of Labor Hygiene of the Ministry of Railways. The main drafters of this standard are Zheng Tianen and Wang Side. 108
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