Measurement and bio-dynamic model development of seated human subjects exposed to low frequency vibration environment

Abstract

In this study, the effect of posture, vibration magnitude and frequency on seat-to-head (STH) and back support-tohead (BTH) transfer functions has been studied under vertical sinusoidal vibration. Twelve healthy male subjects were participated in experimental work to measure vertical vibration transmitted to the occupants head in three representative postures (erect, vertical back on and forward lean on table) under three magnitudes of vibration (0.4, 0.8 and 1.2 m/s 2 r.m.s.) in frequency range 1 to 20 Hz. From collected data sets, the effect of vibration magnitude, vibration frequency and postures on STH and BTH transmissibility's and phase has been drawn over the prescribed frequency range. The result suggested that inclusion of all possible variables in optimal design of vehicle seat, suspension and comfort analysis most benefit for better design and analysis. The comparison of experimental and model response reveals that both models matched with mean experimental data sets most closely and the models provide best description about biodynamic response study of seated human subjects under vertical whole body vibration.

Modal analysis of human body vibration model for Indian subjects under sitting posture

“…Results obtained clearly establish decoupling of vertical and fore-and-aft oscillations. The results have been compared with the values available in the literature and it was found that the eigenvalues evaluated in the present work are comparable with the resonant frequency peaks obtained from the experimental data given by Harsha et al (2014), Gupta (2007), Griffin (1997, 1998) and Rutzel, Hinz, and Wolfel (2006).…”

“…The present study deals with a nine-DOF lumped parameter model developed by Harsha et al (2014) in order to study the response of seated human body to the vertical and horizontal whole-body vibrations, considering five segments of masses interconnected by four vertical and two horizontal springs and dampers such that seat and feet are fixed with respect to floor with the help of two vertical and two horizontal springs and dampers with hands resting on the lap. This model has been modified in the present study for which anthropometric data of Indian male subjects have been taken from Chakrabarti (1997).…”

“…Nigam and Malik (1987) used anthropometric model of Bartz and Gianotti (1975) to identify the body segments (as shown in Figure 1) and modelled a 15-DOF vibratory model (as shown in Figure 2) to calculate stiffness of 14 interconnecting springs and corresponding mass, stiffness and natural frequency of 15 segments. In this study, a nine-DOF lumped parameter model developed by Harsha et al (2014) has been modified, as explained earlier. Its symbolic representation of human body model parameters is given in Table 1.…”

“…Based on ellipsoidal mass segments shown in Figure 1 (Bartz and Gianotti 1975), Nigam and Malik (1987) have established a technique for evaluating the stiffness of body segments (shown in Figure 2), which have been further used by Gupta (2007) and others. Harsha et al (2014) conducted experimentation on 12 Indian male subjects and developed a biodynamic model for seated subjects and came to the conclusion that mathematical models provide best description for biodynamic response study of seated human subjects under vertical whole-body vibration.…”

An improved spinal injury parameter model for underbody impulsive loading scenarios

“…The magnitudes also varied considerably from the standardized values . It can be seen from Figure that the STHT values of the model were within the variations available in the literature …”