Experimental Investigation To Study the Influence of Handle Diameter on Low-Frequency, Hand-Arm Vertical Vibration

Abstract

Handle vibration from equipment or machines influences musculoskeletal activity as well as comfort in handling the same. New technology can be worse than no technology if it was not developed correctly as ergonomic research has clearly demonstrated the relationship between injury risk and poorly designed hand tools. Clinical and epidemiological studies have shown that operators of handheld power tools are prone to develop various vibration-induced disorders of the hand and arm, which are collectively referred to as vibration syndrome.'' The vibration direction has a great influence on the transmitted vibration. The present study focuses the effects of low-frequency vertical vibration on hand to shoulder from handles of different size. The electrodynamic exciter is used for simulating vibration to a vertical handles of four different diameters. PULSE LabShop software is used for evaluating the magnitude of vibration in different frequency bands. The vibration characteristic data were acquired in the yh axis at the wrist, elbow, and shoulder for bent arm and extended arm postures with vibration excitation of 4.5 m/s2. Transmissibility characteristics are computed to determine the influence of handle diameter in yh vibration transmitted to the hand-arm system. The magnitude of vibration transmitted within the hand, elbow, and shoulder was observed to be dependent on the handle size; larger handles cause higher vibration transmissibility. The results also show that the human hand-arm system in an extended arm posture amplifies the vibration transmitted than bent arm in a small difference. © 2011 Wiley Periodicals, Inc.