Comprational Vibration In India

Chapter - I

INTRODUCTION

India is the seventh largest country by area and the second most populated country in the world with a population of 1,210.6 million (623.1 million males and 587.5 million females). Seventy per cent of the country's population is reliant on agriculture and related activities. The agriculture sector offers a livelihood to about 64 per cent of the labor. This force contributes nearly 26 per cent of GDP and accounts for about 18 per cent share of the total value of the country’s exports. The net sown area is 141.5 million ha. The area and production of pulses, cereal and oilseeds crops in the year 2011 was 26.4, 100.27 and 272.24 million ha. and 17.09, 242.2 and 29.8 millions tons respectively (India, 2014).

Many important mechanical vibrations in tractors lie in the very high frequency range corresponding to rotation speed of 60-6000 rpm. Vibration describes the physical energy from a vibrating object, and also what we feel when that energy is transmitted to us. The main terms used to define this movement are “amplitude” and “frequency”. There are two of vibration occurs on Tractors operators : “segmental vibration” exposure, and “whole body vibration” exposure. Segmental vibration exposure refers to exposure that is mainly transmitted to, and concentrated on, a specific part of the body – such as the hand, arm, or leg. Whole body vibration exposure is when vibration is transmitted throughout all or most of the body. The control of vibration has been limited to vertical vibration effects with respect to a seated operation. Horizontal (lateral and longitudinal) and angular (pitch, roll and yaw) accelerator inputs are also experienced by the seated operations. Design for vibration isolation and control requires detailed analysis or complex vibrations. The amplitude of average mechanical vibration measured at the tractor, which are functionally important with the engine running at its rated speed both on load and unload conditions. Exposure of the human body to vibration can result in biological, mechanical, physiological and psychological effects. The

The allowable exposure time is doubled For every 5 dB decrease in noise level,. OSHA assumed All time/intensity values to have equal risk to each other, for examples 16 hours at 85 dB carries the same auditory risk as 8hours at 90 dB, 4 hours at 95 dB, 2 hours at 100 dB, and so on. Whereas, National Institute for Occupational Safety and Health (NIOSH, 1998) recommends an exposure limit of 85 dBA for 8 hours per day, and uses a 3 dB time intensity tradeoff: for every 3 dB increase in noise level, the allowable exposure time is reduced by half. For every 3 dB decrease in noise level, the allowable exposure time is doubled. The time/intensity values shown on the NIOSH REL line are assumed to have equal risk to each other, that is, 8 hours at 85 dB carries the same auditory risk as 4 hours at 88 dB, 2 hours at 91 dB, and so on. The OSHA and NIOSH noise exposure sacle are presented in Table