A QUICK AND PRACTICAL EXPERIMENTAL METHOD FOR SEPARATING WHEEL AND TRACK CONTRIBUTIONS TO ROLLING NOISE
✍ Scribed by A. FRID
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 200 KB
- Volume
- 231
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
A rapid and inexpensive experimental method for the breakdown of wayside rolling noise into direct and indirect wheel and track components has been developed. &&Direct11 in this context refers to the sound radiation from the outside of wheel and track. &&Indirect'' refers to sound radiation from inside wheel/track parts which is "rst re#ected in the running gear, vehicle subframe and ballast before being radiated to the wayside. The separation method requires simultaneous measurements with a close range highly directive parabolic re#ector microphone and a microphone on the track bed. The method gives the sound power for the above-mentioned components in 1/3-octave bands. For validation, synthesized wayside sound pressure time histories in 1/3-octave bands are compared with measured ones at 5 and 25 m distance from the track. The acoustic model for the source separation also allows a rough assessment on the e$ciency of noise reduction measures like shielding, wheel damping, bogie absorption, etc., to be made. The method is demonstrated on pass-bys of X2000 trains and the potential bene"t of damping, absorption and shielding is discussed.