Railway transport sound measurement

Transcription

1 Railway transport sound measurement Žilina 2010 Tomáš Závodský

2 Contents 1. sound basic information 2. sound measurement 3. sound level meter 4. train sound 5. sound protection

3 Recorded sound of the passing train - model running L paeq [db] time čas

4 Recorded sound of the passing train measured running L paeq [db] Priebeh Sound L paeq of Os the vlaku passenger (prechod train o 12:06), km 35, T p 80 34,2 34,6 35,0 35,4 35,8 36,2 36,6 37,0 37,4 37,8 38,2 38,6 39,0 39,4 time [s] čas [s]

5 1. Sound basic information Sound - is any pressure variation that the human ear can detect. Why is the sound measured? Sound measurement enables sound evaluating. According to measurements carry out the steps. Acoustic measurement important at hearing protection.

6 Sound spreading in surroundings Just like dominoes, a wave motion is set off when an particle of air sets the nearest particle into motion. This motion gradually spreads to next air particle from the source. Sound extends at different speeds: in air m/s (1 200 km/h) in water m/s in steel m/s.

7 Change of pressure related to weather - is too slow - human hearing it does not detect. Sound is - faster pressure change (at least 20 times per second) Frequency - number of pressure variations per 1 second [Hz].

8 Example of the sound with a low frequency drum with a high frequency whistle. Example of the sound: 250 Hz 1000 Hz (1 khz) 4000 Hz (4 khz). Frequency range for the young person hearing: from 20 to Hz (20 khz). Piano frequency range: the lowest tone 28 Hz, the highest tone Hz.

9 The man hear not: frequency lower than 20 Hz infra-sound (hears e.g. elephant) and frequency over 20 khz ultra-sound (hears e.g. dolphin, dog). Sound frequencies frequency [7]

10 Ultra-sound Some animals (e.g. dolphin) use it for orientation and hunting. (they are sending out and receiving ultra-sound), other animals (e.g. dog) can just receive it. Echolocation (of animals) is based on sending out of the high frequency sound in repeated intervals and hearing of the rebounds from the things. In this way they can locate the position and the distance. Ultra-sound using sonar in submarines, for orientation and distance measuring for cleaning (e.g. jewellery).

11 The main acoustic rule In a free space the sound level decrease for 6 db when a distance is doubled. Example: car in a distance 10 m makes the sound 80 db, also at distance 20 m the sound level decrease to 74 db, at distance 40 m at 68 db... Decibel (db) the measurement unit for expressing the relative intensity of sound. Scale in Pa to the measurement of the sound pressure leads to large numbers.

12 Usual sounds and their values in μpa and db. When acoustic pressure increases 10 times = increase for 20 db. surroundings (sound) threshold of hearing typical sound pressure level 20 μpa 0 db in library μpa 34 db loud conversation μpa 54 db truck μpa 94 db concert μpa 104 db plane take off μpa 124 db plane - video

13 2. Sound measurement Placement at sound measurement in an outdoors is: - in front of the building wall - at the distance 1,5 m apart from the wall - at the highness of 1,5 m above the floor level.

14 Podvysoka, beside the railway track Čadca-Makov, March 4, Placement at measurement: - 1,5 m apart from the wall - highness 1,5 m.

15 Podvysoka, March 4. The microphone is about 25 m from the railway track, which runs in front of the trees.

16 Measured value: p L = 10 log A Aeq 2 T p T T 1 ( t) dt A-weighted equivalent level of acoustic pressure. 0 p A(t) p 0 = 20 μpa T - A-weighted immediate sound pressure [Pa] - referenced sound pressure, - evaluating time. db - is a logarithmic ratio of the measured value to a reference value.

17 Allowed transportation noise values are set in regulation 549/2007 about the noise in surroundings [5]. In an outdoor surroundings is evaluating mainly noise from: a) road and water b) railway c) air transport.

18 Allowed transportation noise values (L Aeq ): area category area description time road and water rail air I Area with an special noise protection (e. g. spa). day Area in front of the school II windows, flats and houses, day recreational area. III Area as in category II in a motorways, main roads, railway tracks and airports surrounding, town centres. day even. night IV Industrial areas. 24 h

19 3. Sound level meter Sound level meter - detects the sound in similar way as human hearing - enables sound level measurement. Sound level meter of ŽSR VVÚŽ: - hand held analyzer B K accuracy class 1 - measurement range db - special conical shape - for less sound reflection from device itself.

20 4. Train sound measurement Sound measurement in the railway transport is in compliance with an EN ISO 3095:2001 Railways Acoustics Measurement of noise by railway vehicles [2], which describes measurement conditions.

21 Measurement conditions 1. Acoustic surroundings - ground is within 1 m above the rail. - place should be without snow, high plants or water. 2. Meteorological conditions - the wind speed is within 5 m/s - without raining or snowing. 3. Train composition behind the locomotive is at least 1 acoustic similar wagon followed by at least two measured wagons and at least 1 acoustic similar wagon.

22 4. The track - is usually used on the railway network - dry, without icing - good maintained - track slope is most The microphone placement - on both track sides - 7,5 m from the track axle - at the height 1,2 m above the rail.

23 Recorded sound of the passing train - model running [2] L paeq [db] time čas

24 Recorded sound of the passing train - measured running [VVÚŽ] L paeq [db] Sound Priebeh of the train L paeq vlaku ,2 34,6 35,0 35,4 35,8 36,2 36,6 37,0 37,4 37,8 38,2 38,6 39,0 39,4 Question: time [s] How many wagons has this train? čas [s]

25 Recorded sound of the passing train - measured running (with locomotive and wagons) [VVÚŽ] L paeq [db] Priebeh Sound L paeq of the Os Os vlaku train (prechod o 12:06), km 35, T p 80 34,2 34,6 35,0 35,4 35,8 36,2 36,6 37,0 37,4 37,8 38,2 38,6 39,0 39,4 time čas [s]

26 Railways of the Slovak republik (Železnice Slovenskej republiky) Research institute (Výskumný a vývojový ústav železníc) carries out: - sound measurement of wagons. Place of the measurement railway track Žilina-Bratislava, between: Cífer and Šenkvice km 34,7 34,8.

27 Measured wagons: series Sggrss and Sggmrss (for containers), -2 parts, - 3 carriages. [8]

28 Sggmrss 90 wagon [8] S - flat carriage wagon with 2 parts, gg - for containers, loading length over 60 foots m - with 2 parts, loading length over 27 m r - hinge wagon ss - speed 120 km/h [8]. Sv 1 video

29 The sound of wagons recorded at measurement [VVÚŽ] L paeq [db] T p ,9 25,4 25,9 26,4 26,9 27,4 27,9 28,4 28,9 29,4 29,9 30,4 30,9 31,4 čas time [s]

30 The sound of wagons recorded at measurement - detail [VVÚŽ] L paeq, Tp [db] Priebeh meranej veličiny vlaku Sv 1 v čase T p The sound of wagons T p 27,6 27,8 28,0 28,2 28,4 28,6 28,8 29,0 29,2 29,4 29,6 čas [s]

31 Allowed values L paeq, Tp for wagons passing with speed 80 km/h: values also depends of apl - axles per unit length [m -1 ]. wagons new wagons (apl within 0,15/m) modernised wagons (apl within 0,15/m) L paeq, Tp 82 db 84 db

32 Air transport noise Place of measurement: - highness 4 m above the surface, - in the place, where the reflecting from buildings around is minimal (e. g. at the roof of the highest building).

33 Supersonic civil planes TU December 1968 first flight - June 1969 supersonic flight mail and cargo flights from Moscow to Alma-Ata passenger flights (1 per week). Supersonic plane TU-144 [11]

34 May end of passenger flights 16 planes made. Supersonic plane TU-144 [11]

35 Concorde -nameisfromlatinword unity - French-british supersonic plane - 15 years development - had reached the supersonic speed above the Atlantic Concorde in London [12]

36 Development: - March 1969 first flight - October 1969 supersonic flight flights over Atlantic in one day line London New York first flight around the world 30 hours Atlantic flight in 2 h 53 min London - New York flight ticket - about Euro. Travelling speed km/h, passenger number: 100 to 144 [12].

37 5. How to prevent from the noise: 1. shorten staying in a noisy surrounding 2. reduce noisy concerts and disco attending 3. TV, radio, mp3 players - choose appropriate sound volume 4. noisy activities - do not carry out in a small room - (repairing in a flat) do in a daily time 5. time spending in the delightful silent surroundings (in a park, outdoors).

38 Literature 1. Měření zvuku. Príručka B a K. 2. STN EN ISO 3095 Železnice. Akustika. Meranie hluku emitovaného koľajovými vozidlami. 3. Ručný analyzátor zvuku Technická dokumentácia. 4. Hand held analyzer type Product data. 5. Vyhláška Ministerstva zdravotníctva SR 549/ Servan-Schreiber, E; Stapleton, M.: Lexikon der griechischen und römischen Mythologie, Xenos Verlagsgesellschaft, Hamburg Česká hudební společnost. CD en.wikipedia.org 10. sk.wikipedia.org/wiki/zvuk 11. aero.sme.sk

39 Thank you for your attention