An Analysis of Vibration

2299 WordsFeb 17, 20189 Pages
An oscillating motion of a particle or body about a reference point which is fixed is known as vibration. This motion is sinusoidal i.e., simple harmonic or otherwise non sinusoidal i.e., complex. This can occur in different modes as translational or bending modes and, since the vibration can occur in more modes at a time, vibration analysis is very much difficult. Units of vibration The units of vibration depend on the vibrational parameter as follows: • Acceleration in units of m/s2. • Velocity in units of m/s. • Displacement in units of m. Some effects of vibration Vibration can cause damage to structures and machine sub-assembly, resulting in mis-operation, excessive wear, or even fatigue failure. Vibration may have adverse effects on human beings. The primary effects are task-performance interference; motion sickness; breathing and speech disturbance; and a hand-tool disease known as “white finger”, where the nerves in the fingers are permanently damaged, resulting in loss of touch sensitivity. Characteristics of vibration Vibration may be characterized by: a) The frequency in Hz; b) The amplitude of the measured parameter, which may be displacement, velocity, or acceleration. This is normally referred to as the vibration amplitude when expressed in units, but vibration level when expressed in decibels. Decibel notation applied to vibration measurement Because of the wide range of vibration amplitudes found in engineering, it is convenient to express the
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