Experimental Investigation of Low-Frequency Noise and Vibration in a Bus

Selvaraj, Krishnamoorthy; Padavala, Prasad; Rajamohan, Karalmarx; Medisetti, Jaganmohan Rao

doi:10.4271/2020-01-5082

Cited by 3 publications

(2 citation statements)

References 5 publications

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“…Besides thermal comfort and IAQ, other factors such as noise and lighting [27] impact the well-being and health of exposed commuters in these LTCs. Specifically, noise, vibration, and harshness (NVH) are critical factors, even in buses, that impact comfort, health, and safety [28]. Additionally, for trains, other parameters besides light and noise, such as aural comfort, acceleration effects, vibration, and seat static comfort [29,30], are critical to achieving passenger comfort and safety.…”

Section: Introductionmentioning

confidence: 99%

A Field Survey on Indoor Climate in Land Transport Cabins of Buses and Trains

Ogundiran,

Nyembwe,

Ribeiro

et al. 2024

Atmosphere

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Assessing indoor environmental quality (IEQ) is fundamental to ensuring health, well-being, and safety. A particular type of indoor compartment, land transport cabins (LTCs), specifically those of trains and buses, was surveyed. The global rise in commute and in-cabin exposure time gives relevance to the current study. This study discusses indoor climate (IC) in LTCs to emphasize the risk to the well-being and comfort of exposed occupants linked to poor IEQ, using objective assessment and a communication method following recommendations of the CEN-EN16798-1 standard. The measurement campaign was carried out on 36 trips of real-time travel on 15 buses and 21 trains, mainly in the EU region. Although the measured operative temperature, relative humidity, CO2, and VOC levels followed EN16798-1 requirements in most cabins, compliance gaps were found in the indoor climate of these LTCs as per ventilation requirements. Also, the PMV-PPD index evaluated in two indoor velocity ranges of 0.1 and 0.3 m/s showed that 39% and 56% of the cabins, respectively, were thermally inadequate. Also, ventilation parameters showed that indoor air quality (IAQ) was defective in 83% of the studied LTCs. Therefore, gaps exist concerning the IC of the studied LTCs, suggesting potential risks to well-being and comfort and the need for improved compliance with the IEQ and ventilation criteria of EN16798-1.

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Section: Introductionmentioning

confidence: 99%

A Field Survey on Indoor Climate in Land Transport Cabins of Buses and Trains

Ogundiran,

Nyembwe,

Ribeiro

et al. 2024

Atmosphere

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“…Notably, Kim and Altinsoy [1] concentrated their research on booming noise emanating from engines and powertrain drivetrains. Selvaraj et al [2] analyzed low-frequency noise and vibration problems in bus bodies, which stem from imbalances in large bus propeller shafts, using the operational deflection shape (ODS) technique. Herrmann et al [3] investigated the mechanisms behind the booming noise generated by coupling modes between the rear axle and vehicle body, which subsequently affect the fore-aft behavior of tailgates and the acoustics within the vehicle interior.…”

Section: Introductionmentioning

confidence: 99%

Strategies for Reducing Booming Noise Generated by the Tailgate of an Electric Sport Utility Vehicle

Kim,

Jeon,

Lee

et al. 2023

Applied Sciences

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This article investigates the source of booming noise emanating from the tailgate of an electric sport utility vehicle (SUV), along with proposed strategies to mitigate it. This annoying low-frequency booming noise, which significantly impacts interior sound quality, is less perceptible in conventional internal combustion engine vehicles. However, this noise is more readily detected in electric SUVs, highlighting the necessity for focused measures to reduce it. This study involved the measurement of booming noises during on-road vehicle tests to pinpoint their origins. Additionally, ODSs were extracted from the tailgate vibration signals to gain insight into its dynamic behavior. Modal tests were conducted on the tailgate to determine its dynamic characteristics and compared with driving test results to reveal the mechanism responsible for tailgate-induced booming noise. It was established that such noise is primarily due to the tailgate modes, resulting from a combination of rigid body motion in the fore-aft direction and deformation in the central section of the panel. An analytical model of the tailgate was developed using commercial finite-element analysis software to propose measures for reducing booming noise. Experimental findings validated this model’s accuracy. Structural enhancements were implemented to enhance the panel stiffness and improve the connection between the vehicle and tailgate via bushings to reduce the booming noise resulting from tailgate motion. Under random force inputs, the analytical results demonstrated a 13.8% reduction in maximum deformation in the tailgate model in the improved structural configuration with increased panel stiffness. This study identifies the mechanism generating booming noise, establishes a practical and simple dynamic model, and proposes improvement measures aimed at reducing the booming noise.

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