Ishbir Singh

Agricultural tractor operators are exposed to high intensity of vibration during working conditions which significantly affect operator's health. In this research work, FEM analysis of tractor seat has been performed to evaluate the transmissibility from seat base to seat pan for the tractor operator representing 95th percentile male population of India. It has been found that tractor seat shows maximum transmissibility between 2 to 6 Hz. This can cause motion sickness, back pain and other health related issues. To improve ride quality of tractor operator, three different spring stiffness i.e. 0.3 kg/mm, 0.55 kg/mm and 0.7 kg/mm have been considered for the minimum transmissibility. Seat suspension with stiffness of 0.55 kg/mm has maximum transmissibility of 1.47 at 3.7 Hz which has been found to be comparatively 16% less than other stiffness values considered in this study.

Human body is exposed to vibration in daily life activities like travelling, heavy machinery work, agriculture operations etc. The aim of present study is to evaluate the effect of whole body vibration on various human body segments. A three layer 3D CAD model has been modelled according to 95th percentile Indian human male anthropometric data with three different layers for defining the properties of human bone, skin and muscles, respectively. Human model has been excited at RMS value of 0.5, 1.0 and 1.5 m/s in a frequency range from 0-20 Hz. 3D model of farm tractor seat has been also developed using reverse engineering. Human model and tractor seat have been assembled with each other and RMS value ranging from 0.5-1.5 m/s has been applied on the seat to find out the seat to head transmissibility. Damping ratio of human body has been considered to be 0.2, 0.3 and 0.5. The seat has been considered with three spring stiffness 0.3, 0.55 and 0.7 kg/mm for suspension system. It has been found that maximum deformation occurs at head and primary resonance frequency has been found to be in the range of 4-6 Hz.