Effects of sitting postures on biodynamic response of seated occupants under vertical vibration

Wang, W.; Rakheja, S.; Boileau, P.-É.

Affiliations

¹Department of Mechanical engineering, CONCAVE Research Centre, Concordia University, 1455 de Maisonneuve West, Montreal, Québec, Canada H3G 1M8

²Institut de recherché Robert-Sauvé en santé et en sécurité du travail, 505 de Maisonneuve West, Montreal, Québec, Canada H3A 3C2

Abstract and keywords

The biodynamic response characteristics of 13 male and 14 female seated subjects, exposed to vertical vibration, are characterized under different postural conditions. The measurements are performed for a total of 36 different sitting postural configurations realized through variations in hands position (in lap and on steering wheel), three seat heights (510, 460 and 410 mm), and seat design factors involving two different pan orientations (0° and 7.5°) and three different back support conditions (no support, and support with vertical and inclined backrest). The measured data, expressed in terms of the vertical apparent mass (APMS), are analyzed to study the effects of sitting posture on the biodynamic response under whole-body vertical vibration. Owing to the complex dependence of apparent mass response on the body mass, the statistical analyses are performed with body mass as a covariant. The results suggest that the hands in lap posture yields larger primary resonant frequency and considerably higher APMS magnitude response in the vicinity of primary resonant frequency than the hands on the steering wheel posture, when the back is supported with an inclined backrest. The apparent mass magnitudes at frequencies above the primary resonance tend to increase when the back is supported irrespective of the hands position. A higher seat height yields higher peak magnitude response which is attributed to relatively larger portion of the body mass supported by the seat, while the influence of seat pan inclination is observed to be negligible for range of inclination investigated.

Relevance to industry: The apparent mass of seated occupants exposed to whole body vibration yields significant information on human response to vibration, and forms the basis for developing analytical models representing the seated human body, and for potential applications in assessment of coupled occupant system and design of automotive seat. The knowledge of influence of various design and operating factors, and some of the anthropometric factors is vital to realize better seat design.

Keywords: Apparent mass; Biodynamic response of seated occupants; Sitting posture; Whole-body vibration; Body mass effect; Sitting posture variations; Hands position; Seat height; Covariance analysis

Links

DOI: 10.1016/j.ergon.2004.04.009

WoS: 000224001400005

History

Received: 2004-01-05

Accepted: 2004-04-26

Online: 2004-06-15

Cited Works (8)

Year	Entry
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Cited By (12)

Year	Entry
2008	Patra SK, Rakheja S, Boileau P-É, Nelisse H, Boutin J. Defining reference values of vertical apparent mass of a seated body exposed to vibration. In: Proceedings of the 2nd American Conference on Human Vibration. June 4-6, 2008; Chicago, IL.57-58.
2012	Dewangan KN, Shahmir A, Rakheja S, Marcotte P. Gender effect on the seated body apparent mass response to vertical whole body vibration. In: Proceedings of the 4th American Conference on Human Vibration. June 13-15, 2012; Farmington, CT.10-11.
2012	Harnish C, Eger T, Godwin A, Dickey JP. Examining the impact of non-neutral sitting postures on vibration transmissibility from seat to head. In: Proceedings of the 4th American Conference on Human Vibration. June 13-15, 2012; Farmington, CT.62-63.
2019	Cavacece M, Aghilone G. Influence of leg posture on vibration characteristics of a passenger car. In: 54th UK Conference on Human Response to Vibration. September 24-26, 2019; Edinburgh, UK.
2014	Zhou Z, Griffin MJ. Response of the seated human body to whole-body vertical vibration: biodynamic responses to sinusoidal and random vibration. Ergonomics. May 2014;57(5):693-713.
2008	Liang C-C, Chiang C-F. Modeling of a seated human body exposed to vertical vibrations in various automotive postures. Ind Health. April 2008;46(2):125-137.
2007	Mansfield NJ, Maeda S. The apparent mass of the seated human exposed to single-axis and multi-axis whole-body vibration. J Biomech. 2007;40(11):2543-2551.
2011	Zheng G, Qiu Y, Griffin MJ. An analytic model of the in-line and cross-axis apparent mass of the seated human body exposed to vertical vibration with and without a backrest. J Sound Vibrat. December 19, 2011;330(26):6509-6525.
2011	Madakashira-Pranesh A. Experimental and Analytical Study of Transmission of Whole-Body Vibration to Segments of the Seated Human Body [PhD thesis]. Concordia University; March 2011.
2016	Byrnell HK. Personal Protective Equipment as a Control Strategy to Reduce Foot-Transmitted Vibration [Master's thesis]. Sudbury, ON: Laurentian University; 2016.
2015	Solbiati S. Human Body Response to Multi-Axial Dynamical Vibrations [PhD thesis]. Milano, Italy: Politecnico Di Milano; January 2015.
2011	Conrad LF. Whole-Body Vibration on Mobile Machines Within the Steel Making Industry: Assisting Industries With Proper Seat Selection to Retrofit Existing Machines [Master's thesis]. Guelph, ON: University of Guelph; January 2011.