Authors: Jonathan DeShaw; Salam Rahmatalla
Addresses: Center for Computer-Aided Design, College of Engineering, The University of Iowa, Iowa City, IA 52242, USA ' Civil and Environmental Engineering, The University of Iowa, 4121 Seamans Center for Engineering, Iowa City, IA 52242-1527, USA
Abstract: Effective seat-to-head transmissibility (ESTHT) is introduced in this work to objectively evaluate human biodynamical response in a six-degree-of-freedom input/output vibration environment. In ESTHT the complex transmissibility matrix is transformed to simple forms that can be easily interpreted. In this study, human responses were compared using ESTHT under different seated postures, including an upright seated posture with no backrest, a backrest-supported sitting posture, a backrest-supported sitting posture with forearms resting on armrest supports, and a backrest-supported sitting posture in which participants used the armrest supports and rotated their heads to the side. Twelve healthy males participated in the study and were tested under random-vibration files of 0.5-12 Hz with different magnitudes. The results showed the capability of ESTHT to identify the frequency spectrum at which the motion is magnified. The study also revealed that ESTHT was able to detect differences in human response due to different postures and vibration directions.
Keywords: whole-body vibration; seat-to-head transmissibility; seated postures; measurement; accelerometer; transfer function; single-value decomposition; multi-axis motion; vehicle performance; combined-axis vibration; multiple postures; human biodynamics; biodynamic response; vehicle vibration.
International Journal of Vehicle Performance, 2014 Vol.1 No.3/4, pp.235 - 253
Received: 04 May 2013
Accepted: 12 Dec 2013
Published online: 28 Apr 2015 *