2013-05-01 12:00 - Messages

Identification of quality attributes of automotive idle sounds and whole-body vibrations

The aims of this study are the generation and comparison of the semantic spaces of vehicle idling sounds and vibrations and the determination of their quality dimensions. In this study, two different sets of quality attributes were developed for idling sounds (34 attributes) and whole-body vibrations (22 attributes). In contrast to prior investigations, the results demonstrated that the sound level alone is an insufficient attribute for describing the complexity of idle sounds and vibration perceptions. The qualities of both idle sounds and idle vibrations have multidimensional, complex characters. The results show that intensity-dependent attributes, signal-based attributes in terms of spectrum and temporal properties, and comfort- and emotion-based attributes are all required to characterise the idling noise, vibration, and harshness (NVH) performance of vehicles. Therefore, an index was proposed based on psychoacoustic metrics such as loudness, sharpness, roughness, fluctuation strength, and relative approach. The results also show that emotional aspects play an important role for the assessment of sound and vibrations.

Source :
M. Ercan Altinsoy ,International Journal of Vehicle Noise and Vibration, Vol. 9, No. 1/2, 2013. http://dx.doi.org/10.1504/IJVNV.2013.053814

Comprehensive measurement in whole-body vibration

Accurate measurements of human response to whole-body vibration are essential to any conclusions about the health risks, discomfort, and assessment of suspension systems in vibration environments. While accelerometers are traditionally considered the main measurement tools in whole-body vibration studies, their measurements become questionable when they are attached to inclined surfaces or when the motion has coupled components in multiple directions. Current measurement correction methodologies are subjective and limited to simple cases. A comprehensive correction methodology using inertial sensors was used in this work to quantify human response under single fore-aft, single-vertical, and multiple-axis whole-body vibration of twelve seated subjects with supported-backrest and unsupported-backrest upright posture. Vibration files of white noise random signals with frequency content of 0.5-12 Hz and vibration magnitude of 1.8 m/s2 RMS were used in the testing. The results have shown considerable differences in the transmissibility measurements without proper correction. The work presented has the potential to standardize experimentation in whole-body vibration and make measurements more accurate and defined across labs.

Source :
Jonathan DeShaw, Salam Rahmatalla. Noise Notes, vol. 12, no 1, 2013, p. 27-38.

Survey of noise emission and risk information suppllied with a range of work machinery - RR962

Previous work has shown that the noise emission data provided by the manufacturers can be of variable quality and be based on standards that no longer exist. In some cases no noise emission data are provided at all. The Health and Safety Executive (HSE) needs to be in a position to challenge or support the validity of noise emission data or other information provided by manufacturers, to offer robust advice to dutyholders on the management of noise exposure based on this information, and facilitate the promotion of low noise machinery on a general or machine specific basis. The aim of the project was to assess the suitability of information on noise emission required under the Supply of Machinery (Safety) Regulations and the Noise Emission in the Environment by Equipment for Use Outdoors Regulations for workplace risk assessment. The noise information provided by manufacturers and suppliers of a wide range of machine types for which noise declaration is required was assessed.

Source : http://www.hse.gov.uk/research/rrpdf/rr962.pdf

Promoting Hearing Health among Fire Fighters

Exposure to high noise levels among fire fighters is well documented and increases the risk for noise-induced hearing loss. NIOSH recommends measures to promote better hearing health through the use of quieter equipment, better work practices, hearing protection devices, and implementation of effective hearing loss
prevention programs.

Source : http://www.cdc.gov/niosh/docs/wp-solutions/2013-142/pdfs/2013-142.pdf

Emotional stress may affect sound perception

A fresh article by researchers including Dan Hasson at Karolinska Institute and the Stress Research Institute in Stockholm, Sweden concludes that emotional exhaustion in women affects their sound perception in a negative way. The sample of subjects were taken from SLOSH (Swedish Longitudinal Occupational Survey of Health) and followed up with additional data collection. After being provoked with an acute stress task women who had scored high on emotional exhaustion also showed a greater sensitivity to sounds. This study supports the theory that hearing problems such as hyperacusis (auditory sensitivity) may be stress induced and that emotional exhaustion should be taken into account in the diagnosis and treatment of hearing problems.

Source : Hasson D, Theorell T, Bergquist J, Canlon B .  Acute Stress Induces Hyperacusis in Women with High Levels of Emotional Exhaustion. PLoS ONE 8(1) 2013. http://dx.doi.org/10.1371/journal.pone.0052945


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