Abstract
When a whole body is exposed to vertical vibration, the body’s asymmetric shape affects the response to translational and rotational motion. The degree of asymmetry of a body on a seat is affected by posture. In our study, sixteen male subjects sitting on a seat were used to obtain a response to vertical vibration over a frequency range of 3 to 40 Hz. Two kinds of magnitude of the vibration at each frequency were applied (0.224 m/s2 and 0.708 m/s2 RMS). Without a backrest, three kinds of sitting postures (average thigh contact P1, supported thigh contact P2, and minimum thigh contact P3) were set by adjusting the height of the footrest and by using an inclined seat pan. The vertical and rotational responses were measured using a force plate mounted on a rigid seat. The apparent eccentric mass (AEM) is defined in this study as rotational response of body to vertical whole body vibration exposure. In the result, the AEM of P2 posture was bigger than that of P1 and P3 posture, especially in a frequency range of 20 to 40 Hz where idle vibration of the passenger vehicle exists. The apparent mass (AM) was even changed by the three kinds of sitting posture, but the difference was not as much as in the case of the AEM. The bigger difference of the AEM is assumed that the sitting posture mainly affects the asymmetry of the fore-and-aft direction, which is more strongly correlated with the rotational pitch response.
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Min-Seok Kim received his B.S., M.S., and Ph.D degrees from Pusan National University in 2003, 2005, and 2010, respectively. Dr. Kim is currently a full time Research Engineer at the Research Institute of Mechanical Technology at Pusan National University. His research interests are in human vibration and multi-body dynamics.
Gyeoung-Jin Jeon received his B.S. degree from Yeungnam University in 2010. He is currently a candidate for the M.S. degree in Pusan National University from the Department of Mechanical Engineering. His research interest is in human vibration and computer aided engineering analysis of radiated noise.
Jae-Young Lee received his B.S. degree from Pusan National University in 2011. He is currently a candidate for the M.S. degree in Pusan National University from the Department of Mechanical Engineering. His research interest is in human vibration.
Se-Jin Ahn received his B.S., M.S., and Ph.D. degrees from Pusan National University in 1994, 1996, and 2003, respectively. Dr. Ahn is currently a Senior Manager in the Vehicle Quality Engineering Department of the Renault Samsung Motors Company. His research interest is in human vibration.
Wan-Suk Yoo received his B.S. degree from Seoul National University in 1976, the M.S. degree from Korea Advanced Institute of Science and Technology in 1978, and the Ph.D degree from the University of Iowa in 1985. Dr. Yoo is currently a Professor in the School of Mechanical Engineering at Pusan National University, and served as President of Korean Society of Mechanical Engineers in 2011. His main interests are in flexible multi-body dynamics and vehicle dynamics.
Weui-Bong Jeong received his B.S. degree from Seoul National University in 1978, the M.S. degree from Korea Advanced Institute of Science and Technology in 1980, and his Ph.D from Tokyo Institute of Technology in 1990. Dr. Jeong is currently a Professor in the Department of Mechanical Engineering at Pusan National University, Busan, Korea.
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Kim, MS., Jeon, GJ., Lee, JY. et al. Human response of vertical and pitch motion to vertical vibration on whole body according to sitting posture. J Mech Sci Technol 26, 2477–2484 (2012). https://doi.org/10.1007/s12206-012-0626-x
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DOI: https://doi.org/10.1007/s12206-012-0626-x