Multibody Biomechanical Modelling of Human Body Response to Direct and Cross Axis Vibration

Abstract Operators of the vehicles and heavy earth moving machinery are continuously exposed to low frequency whole-body vibration (WBV) of comprehensive magnitudes arising from tire/track-terrain interactions. Research studies shown a high presence of back disorders such as disc degeneration, muscular pain, among the occupational vehicle drivers subjected to whole-body vibration. The modelling and measurement of the biodynamic response of human body is major research topic, with applications to ergonomics, paasive or active suspension control system technologies, adverse effects on the human body that causes discomfort and some health issues. The risk of the vibration exposure depends on three different factors: the time span, the amplitude and the frequency of the transmitted vibration. In the field of automotive engineering, manufacturers and designers require to understand how the acceleration signals are amplified or damped by the human-seat interface in order to increase human comfort. Most of human body models reported in literature are lumped parameter. The limitation with lumped parameter model is that they can be analysed in one direction only. Human body is having complex motion so minimum two dimensional (2D) model need for analysing human body response. The models considered two objective functions with considering vertical or fore and aft vibrations. Multibody human body models of 20 degree of freedom (DOF) developed for seated human, and model parameters are optimized using genetic algorithm (GA) for published experimental data from literature. Model is able to match the published experimental data for Seat to Head Transmissibility (STHT) and Apparent Mass (AM).