ABSTRACT

Vibration is dened as motion that repeatedly alternates in direction. e motion of tides and ocean waves, the shaking of the Earth’s crust during earthquakes, the movement of pistons within the cylinders of engines, the disturbances generated in aircra ying through turbulent air, and the disturbances in vehicles travelling over uneven terrain are all forms of vibration. ey are also examples of vibration that can be transmitted to the human body and may result in a range of physiological and psychological eects. Vibration generally is transmitted to the body through direct contact with a vibrating structure. In these conditions, signicant levels of vibrational energy can be transferred to the body, with potentially harmful consequences. Vibration may also reach the body by transmission through air. Airborne vibration, if in the appropriate frequency range, is perceived as sound, but at low sonic and subsonic frequencies it may exert other physiological eects.