Mechanical Vibration

The study of vibration is concerned with the oscillatory motion of bodies and the forces associated with them. All bodies possessing mass and elasticity are capable of vibrating. Thus most engineering machines and structures experiences vibration to some degree. Undesirable vibration in machines may cause the loosening of parts

Cause of vibration
1. Unbalanced forces –within machine itself,non-uniform material distribution
2. Dry friction between the two mating surfaces
3. External Excitation
4. Elastic nature of the system
5. Earth Quakes
6. Winds


Effect of vibration
• Excessive stress
• Undesirable noise
• Loosening of parts
• Partial or complete failure of parts



Uses
• Musical instruments
• Vibrating screen
• Shakers
• Stress relieving


Methods to reduce vibration
1. Removing the cause of vibration
2. Putting in screens if noise is the only objection
3. Resting the machinery in proper type of isolators
4. Shock Absorbers
5. Dynamic vibration absorber