VIBRATION
*Vibration refers to mechanical oscillations about an equilibrium point.
*In its simplest form,vibration can be considered to be the oscillation (or) repetitive motion of an object around an equilibrium position.
1.Longitudinal Vibration
*When the particle of the body moves parallel to the axis of body then vibrations are known as longitudinal vibration.
2. Transverse Vibration
*When the particle of the body moves perpendicular to the body axis then vibrations are known as transverse vibration.
3. Torsional Vibration
*When the particles of the body moves in a circle about the axis of the body then vibrations are known as torsional vibrations.
4. Free (or) Natural Vibration
*When no external force acts on a body, then it give an initial displacement and then body undergoes vibratory motion, is known as natural vibration.
5. Forced vibration
*When body vibrates under an external force then the body is said to be under force vibration. The vibration has the same frequency at the external force.
6. Damped Vibration
*When there is a reduction in amplitude over every cycle of vibration, the motion of the body to be damped vibration.
WHIRLING SPEED OF THE SHAFT
*Whirling speed of the shaft is also known as critical speed of the shaft.
*It is defined as the speed at which the shaft runs so that the additional deflection of the shaft form the axis of rotation becomes infinite.
