Abstract

Use of hand-held grinding machines can cause excessive vibrations of the hand-arm system. Continued use of these vibrating tools has been found to be connected with various patterns of diseases affecting the blood vessels, nerves, bones, joints and muscles of the hand and forearm. The most severe symptom of prolonged exposure to hand-transmitted vibrations is the Vibration Induced White Finger (VWF) disease. The development of these disorders depends on the level of acceleration produced by the tool. In this thesis, the tool vibrations transmitted to the operator's hand and arm is investigated. A grinder model is developed and the calculated natural frequencies have been validated through laboratory experiments. Further, a two degrees-of-freedom (DOF) lumped parameter model of the human hand-arm system is developed, along each of the three orthogonal directions in order to identify the parameters of the hand-arm vibration (HAV) models using the reported mechanical impedance data and nonlinear programming based optimization technique.