STUDY OF HAND ARM VIBRATION ON DRILL. OPERATOR

Abstract

The variations in contact force between the hand and a vibrating tool handle affect the nature of vibration transmitted to human hand—arm system, and the stresses imposed on the anatomical structure of the system. Long-term_ use of certain portable power tools tends to cause symptoms in the hand and fingers. This study includes the solid modelling of the human hand and its modal analysis. The solid model created in 'Solidworks' converted into 'PARASOLID' file and exported to `Abaqus' for the modal analysis. `Abaqus' has the ability to generate a tetrahedral mesh from a well conditioned surface mesh. The experiment has been done to compare the transmissibility from `handle to wrist' and `handle to elbow'. In this study, the transmission of z-axis and y-axis handle vibration to the wrist and elbow of the human hand and arm are characterized in the laboratory for the horizontal and vertical direction. The experiments involved six male subjects grasping an impact drill machine of 6.5 mm diameter drill subjected to broad-band random vibration targeted on wooden plank and cast iron plate. The result shows the different mode shapes of the human hand under single degree of freedom system. It also shows the resonance peak occurs at 50 Hz and 200 Hz on both points and the transmissibility is always higher at wrist compared to elbow