Biodynamic Response and Spinal Load Estimation of Seated Body in Vibration Using Finite Element Modeling

Abstract

Trunk biomechanical models play an indispensable role in predicting muscle forces and spinal loads under whole-body vibration (WBV) exposures. Earlier measurements on the force-motion biodynamic response (impedance, apparent mass) at the body-seat interface and vibration transmissibility (seat to head) have led to the development of different mechanical models. Such models could simulate the overall passive response and serve as an important tool for vehicle seat design. They cannot, however, evaluate physiological parameters of interest under the WBV. On the contrary, anatomical models simulating human's physiological characteristics can predict activities in muscles and their dynamic effects on the spine. In this study, a kinematics-driven nonlinear finite element model of the spine, in which the kinematics data are prescribed, is used to analyse the trunk response in seated WBV. Predictions of the active model (i.e., with varying muscle forces) as compared with the passive model (i.e., with no muscle forces) compared satisfactorily with measurements on vertical apparent mass and seat-to-head transmissibility biodynamic responses. Results demonstrated the crucial role of muscle forces in the dynamic response of the trunk. Muscle forces, while maintaining trunk equilibrium, substantially increased the compression and shear forces on the spine and, hence, the risk of tissue injury.

An active head–neck model in whole-body vibration: Vibration magnitude and softening

“…Previous studies have been conducted with the goal of investigating and finding an explanation for the nonlinearity of the upper body in response to different vibration magnitudes (Nawayseh and Griffin, 2005;Hinz et al, 2010;Wang et al, 2010). The objective of this work is to investigate the types of nonlinearity in the head-neck response under fore-aft WBV of different magnitudes.…”

“…While experimentations may provide significant insight into human biodynamics during vibration Griffin, 1988, 1998;Rahmatalla et al, 2010;Rahmatalla and DeShaw, 2011a;Mandapuram et al, 2011;Madakashira-Pranesh, 2011), computer human models (Boileau et al, 1997;Griffin, 2001) may present less expensive tools with a potential for evaluations that go beyond the experimentation's allowable ethical limits and would help in the development of more effective vibration suspension systems. Still, due to the complexity of the motion in whole-body vibration (WBV) (Griffin et al, 1979), the nonlinearity, and the involuntary muscle activation of the human body (Nawayseh and Griffin, 2005;Wang et al, 2010;Hinz et al, 2010), advances in predictive computer human modeling become a challenging issue.…”

“…In these models, discrete massspring-dampers (Qassem et al, 1994;Boileau and Rakheja, 1998;Smith, 2008), rigid bodies connected by viscoelastic elements and muscle groups (Amirouche, 1987;Luo and Goldsmith, 1991), and finite element models (Pankoke et al, 2001;Bazrgari et al, 2008;Wang et al, 2010) were used to model the human body response to vibration. Some of the models (Luo and Goldsmith, 1991;Fritz, 1998;Pankoke et al, 2001) showed good potential in predicting muscle forces and stresses, using in some instances (Buck and Wolfel, 1998) very detailed finite-element-based schemes; however, the validity of these models have to be shown.…”

Measures of internal lumbar load in professional drivers – the use of a whole-body finite-element model for the evaluation of adverse health effects of multi-axis vibration

“…There are other anatomically based FE models, but these are often restricted to only two or three vertebral segments (Niemeyer, Wilke, and Schmidt 2012;Quasim et al 2012;Rohlmann et al 2009;Schmidt et al 2007;Wang et al 2010). Other models include the entire lumbar section L1-L5 or L1 -S1 (Ayari et al 2009;Ayari, Thomas, and Doré 2011;Dreischarf et al 2013Dreischarf et al , 2014Rohlmann et al 2007Rohlmann et al , 2010Schmidt et al 2010).…”

“…Other models include the entire lumbar section L1-L5 or L1 -S1 (Ayari et al 2009;Ayari, Thomas, and Doré 2011;Dreischarf et al 2013Dreischarf et al , 2014Rohlmann et al 2007Rohlmann et al , 2010Schmidt et al 2010). The most comprehensive model was described by Wang et al (2010). Wang's FE model of T12 -S1 spinal motion segments includes the head and is combined with a connector element to simulate the buttock -seat interface (head-to-buttock model).…”