scholarly journals Small Changes in Vehicle Suspension Layouts Could Reduce Interior Road Noise

Vehicles ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 18-34
Author(s):  
Timo von Wysocki ◽  
Jason Chahkar ◽  
Frank Gauterin
Keyword(s):  
Rear Axle ◽  
Layout Design ◽  
Vehicle Suspension ◽  
Noise Levels ◽  
Road Noise ◽  
Transfer Path ◽  
Design Changes ◽  
Early Development Phase ◽  
Passenger Cabin ◽  
Lower Noise

Inside the passenger cabin of modern cars, lower noise levels from quieter engines make road noise more dominant. The main transfer path for road noise below 300 Hz into the car is the suspension. Suspension layouts are mainly determined by driving dynamics, but their influence on road noise is not in focus. Layout design changes for driving dynamics in the early development phase require the modification of structural dynamics Finite Element (FE) models used to predict interior acoustics. This manual modification makes acoustical effects from layout design changes difficult to predict. In the following article, we present a method to adapt suspension FE models automatically to suspension layout changes. This allows an automatic optimization of the suspension layout regarding road noise. As an example, a rear axle suspension layout is modified to decrease road noise between 60 and 90 Hz by moving the connection point between the track rod and the knuckle.

scholarly journals Road Noise Levels in Urban Environment Compared to Specification Limits. The Case of the City of Larissa, Greece

2020 ◽  
Author(s):  
Emmanouil A. Papadimitriou ◽  
Grigorios P. Papageorgiou ◽  
Nikolaos Alamanis ◽  
Theodosia-Niki Diakosavva
Keyword(s):  
Road Traffic ◽  
Traffic Noise ◽  
Road Traffic Noise ◽  
Noise Levels ◽  
Road Noise ◽  
Greek City ◽  
Limit Values ◽  
High Noise ◽  
Specification Limits ◽  
The City

Greece, as well as other developed countries, is facing the growing problem of road traffic noise. It stands for a severe problem in the urban areas of the country, including the city of Larissa. The root cause is the huge increase in traffic volume and the lack of adequate urban infrastructure planning. Estimation of the level of road traffic noise is usually conducted using acoustic meters. It is widely accepted that most of the cities’ population is exposed to high noise levels due to controversial traffic capacity. Moreover, high noise levels are strongly related to phycological and neurological diseases. Thus, it is of utmost importance, the road noise levels to be lower than dictated by relevant specification limits. To develop better noise-environment policies, relative research should focus on the measurement of in-situ noise levels, so as appropriate for each case corrective measures to be taken. The present paper examines the noise levels of a center road of the 5th Greek city, in terms of population, compared to worldwide adopted noise specification limits. The clear aim stands for finding the percentage of road noise that exceeds commonly accepted threshold values, namely limit values of European Union and World Health Organization. The results of this research strongly indicate that measured noise values override upper limit values in a certain extent.

Optimized Asphalt Mixtures for Noise Reduction in Lithuanian Roads

2014 ◽  
Vol 614 ◽  
pp. 618-621
Author(s):  
Audrius Vaitkus ◽  
Tadas Andriejauskas ◽  
Laura Čygaitė ◽  
Jurgita Židanavičiūtė
Keyword(s):  
Noise Reduction ◽  
Noise Pollution ◽  
Low Noise ◽  
Asphalt Pavements ◽  
Noise Levels ◽  
Road Noise ◽  
Negative Effects ◽  
Development Experience ◽  
Growing Economy ◽  
Generation Mechanisms

In the world of growing economy and population, the need of transportation is rapidly increasing also raising problems of noise pollution. Environmental noise levels are increasing in parallel with increasing traffic flows resulting negative effects for society, wildlife and economy. The article gives an overview about the main transport noise source tyre/road noise, its generation mechanisms and influencing factors. One of the most effective and promising tyre/road noise solutions is low noise pavements, which has different noise reduction approaches. Low noise asphalt pavements and theoretical noise reduction principles are analysed in the paper as well as the development experience of particular low noise asphalt pavements for Lithuanian conditions.

scholarly journals Reducing Indoor Noise Levels Using People’s Perception on Greenery

2013 ◽  
Vol 11 ◽  
pp. 19-27
Author(s):  
Christina E. Mediastika ◽  
Floriberta Binarti
Keyword(s):  
Prior Knowledge ◽  
Indoor Environment ◽  
Noise Levels ◽  
People’S Perception ◽  
Open Plan ◽  
Insignificant Difference ◽  
Lower Noise

Abstract Employees working in cubicles of open-plan offices in Indonesia were studied in regard to their perception on the ability of indoor greenery to reduce noise levels. Sansevieria trifasciata and Scindapsus sp were used. Each was placed in the cubicle and noise levels were measured without plants, with Sansevieria, and with Scindapsus in place. The meters showed very insignificant difference. However, responses to surveys indicated a perception of lower noise in the presence of greenery. This seemed to be supported by prior knowledge and preconception and may be useful in creating a “quieter” indoor environment.

A Research for the Planetary Gear Noise Development in FF 6th Speed Automatic Transmission

2011 ◽  
Author(s):  
Hyun-Ku Lee ◽  
Koo-Tae Kang ◽  
Moo-Suk Kim ◽  
Jin-Wook Hur
Keyword(s):  
Gear Tooth ◽  
Automatic Transmission ◽  
Planetary Gear ◽  
The Sun ◽  
Noise Levels ◽  
Noise Sources ◽  
Valve Body ◽  
Gear Noise ◽  
Radiated Noise ◽  
Transfer Path

In order to improve the planetary gear noise of the new developed 6th speed automatic transmission, it needs to understand noise mechanism. Basically, many transmission’s components have an effect on the gear noise. In this paper, planetary gear noise sources which are influenced by gear tooth shapes and backlash among the gears, position of pinion gears, and misalignment of the sun gear are studied and experimented. Also, transfer-path likewise one-way clutch contacted between the carrier and case, and valve-body covers are also researched to reduce the transferred vibration and radiated noise levels. After developing the planetary gear noise, its evaluation specification is adapted to EOL (end of line) equipment to check the transmission’s noise quality in the factory.

Classroom Noise and Teachers' Voice Production

2015 ◽  
Vol 58 (5) ◽  
pp. 1397-1406 ◽  
Author(s):  
Leena M. Rantala ◽  
Suvi Hakala ◽  
Sofia Holmqvist ◽  
Eeva Sala
Keyword(s):  
Fundamental Frequency ◽  
Ambient Noise ◽  
Noise Levels ◽  
Working Environments ◽  
Objective Metrics ◽  
Before And After ◽  
Working Day ◽  
Sound Spectrum ◽  
Voice Use ◽  
Lower Noise

Purpose The aim of this study was to research the associations between noise (ambient and activity noise) and objective metrics of teachers' voices in real working environments (i.e., classrooms). Method Thirty-two female and 8 male teachers from 14 elementary schools were randomly selected for the study. Ambient noise was measured during breaks in unoccupied classrooms and, likewise, the noise caused by pupils' activity during lessons. Voice samples were recorded before and after a working day. Voice variables measured were sound pressure level (voice SPL), fundamental frequency, jitter, shimmer, and the tilt of the sound spectrum slope (alpha ratio). Results The ambient noise correlated most often with the fundamental frequency of men and voice SPL, whereas activity noise correlated with the alpha ratio and perturbation values. Teachers working in louder ambient noise spoke more loudly before work than those working in lower noise levels. Voice variables generally changed less during work among teachers working in loud activity noise than among those working in lower noise levels. Conclusions Ambient and activity noises affect teachers' voice use. Under loud ambient noise teachers seem to speak habitually loudly, and under loud activity noise teachers' ability to react to loading deteriorates.

Reduction of Noise at the Design Stage: A Case Study of a Lightly Loaded Assembly

1969 ◽  
Vol 184 (1) ◽  
pp. 593-614 ◽  
Author(s):  
M. A. Satter ◽  
B. Downs ◽  
G. R. Wray
Keyword(s):  
Analytical Study ◽  
Design Stage ◽  
Acoustic Absorption ◽  
Noise Generation ◽  
Noise Emission ◽  
Design Changes ◽  
Damping Materials ◽  
Lower Noise ◽  
Made In

An experimental and analytical study is made of the noise emission from the drawroll assembly of a textile draw-twisting machine. As an alternative to resorting to acoustic absorption techniques or the use of expensive high damping materials, investigations are made into the basic method of noise generation in the assembly. This leads to the incorporation of small design changes and the significantly lower noise emission thereby achieved is compared with the original emission. Aimed at the machine designer, the presentation is made in a straightforward, non-mathematical fashion.

scholarly journals An Efficient Image Denoising Scheme for Higher Noise Levels Using Spatial Domain Filters

2018 ◽  
Vol 11 (2) ◽  
pp. 625-634 ◽  
Author(s):  
Anchal Anchal ◽  
Sumit Budhiraja ◽  
Bhawna Goyal ◽  
Ayush Dogra ◽  
Sunil Agrawal
Keyword(s):  
Image Denoising ◽  
Analog Circuits ◽  
Anisotropic Diffusion ◽  
Additive White Gaussian Noise ◽  
Bilateral Filter ◽  
Noise Levels ◽  
Significant Information ◽  
Edge Information ◽  
Diffusion Filtering ◽  
Lower Noise

Image denoising is one of the fundamental image processing problem. Images are corrupted with additive white Gaussian noise during image acquisition and transmission over analog circuits. In medical images the prevalence of noise can be perceived as tumours or artefacts and can lead to first diagnosis. Similarly in satellite images the visibility of images is significantly degraded due to noise, hence the image denoising is of vital importance. There are many denoising mechanisms given in literature are able to work well on lower noise levels but their performance degrades with increasing noise levels. If higher amount of filtering is applied it leads to degradation or removal of edges from the image and hence significant information. In this paper, we proposed an algorithm in which we are able to address the problem of image denoising at higher noise levels while preserving the edge information. The standard bilateral filter does not provides good results at higher noise levels. Hence we proposed to combine robust bilateral filtering with anisotropic diffusion filtering as the anisotropic diffusion perform the smoothing of homogenous regions without blurring the edges. Experimental results show that the proposed method works better for higher Nosie levels in terms of PSNR values and Visual quality.

scholarly journals Photometric Properties of the Hubble Space Telescope Fine Guidance Sensors

2000 ◽  
Vol 176 ◽  
pp. 82-82 ◽  
Author(s):  
K. Zwintz ◽  
R. Kuschnig ◽  
W. W. Weiss ◽  
A. Witeschnik
Keyword(s):  
Hubble Space Telescope ◽  
Noise Levels ◽  
Space Telescope ◽  
Systematic Effects ◽  
Lower Noise

AbstractTo reach lower noise levels with the Hubble Space Telescope Fine Guidance Sensors (FGS) the photometric properties as well as the systematic effects affecting the data have been investigated.

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