EVALUATION AND IMPROVEMENT OF SONIC ENVIRONMENT IN ELECTRIC RAILWAY TRAIN

• Main Author: Nadya Hartati (13314037), Gary Sebastian Pangihutan (13314083) , Tasya
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31235
• Institution: Institut Teknologi Bandung

<p align="justify">Electric railway train is one of the most widely used means of mass transportation, so it is necessary to note the convenience aspect for its users. One aspect of comfort that is not less important is the acoustic comfort in the train. From the initial measurement, it is known that the maximum sound pressure level on an electric railway train is 80 dB. Eventhough the value still meets the standard of KM. No. 41 Year 2010, but the value does not provide acoustic comfort for passengers. So it can be said on that electric railway train there are dominant sources of noise. Seen in static and dynamic conditions, both have the same noise profile, so it can be said that this noise is not belong to train activity such as rolling noise, vibration in intercoach gap or bogie. From the identification result in the initial survey, it is shown that the dominant noise source lies in the air conditioning system at the dominant frequency (242 Hz). Further analysis tells that the dominant noise of the source component comes from the fan chamber and ducting. The noise in the fan chamber and ducting comes from rotating motors and blade fan as well as vibration in the ducting structure. Therefore, noise control is done by considering air-borne and structure borne transmission path. Noise control is also done by modeling and simulation with a software based on numerical methods. In controlling noise related by air-borne and structure-borne, the improvement is done using case studies For air-borne related noise is done by giving the acoustic liner that enclose the ducting with porous based absorber materials. This improvement provides a decrease in sound pressure level of 29,3 dB. As for controlling the structure-borne related noise is done by changing the geometry of the structure, ie by giving a parallel stiffer on the bottom of the ducting. This improvement provides a decrease in sound pressure level of 28,9 dB. When combining both of the acoustic liner and stiffener, it provides a decrease in sound pressure level up to 37,1 dB, and overall sound pressure level at 51,2 dBA. <p align="justify"> <br />