“Vibration”, a term that tends to induce the same in once's mind when someone hears it. Invariably everything vibrates in the world, some vibrations are good and useful, some are really negligible, some are tolerable, some annoying and the rest fall under the dangerous category.
A vibrating guitar tends to produce soothing music for our ears; a vibrating sieve separates particles of fine sand and coarse sand; the vibrating mode in our mobile phone to alert us without disturbing others. Some good examples of what useful things vibration does to us.
Well some examples of unwanted things vibration does to us; an old running engine vibrating a lot creating a lot of noise unbearable to us; the most dreaded vibration of all the “Earthquake” a random vibration of the earth.
These small vital examples tend to give a glance of the importance that needs to be given to this field. Most of the results arising due to vibration lead to failures, damage of equipment and in worst cases loss of life. Knowing more about vibration helps us to control damage and take preventive measures from damages to occur.
Every machine or appliance that tends to do work by reciprocating or rotating has vibration induced into itself due to its own characteristics. The control of vibration is only possible by measuring it. Some of the important units for the measurement of vibration are
- Displacement , mm or inches
- Velocity, mm/sec or m/sec
- Acceleration, mm/sec^2
There are various type of vibration that tend to get induced due to various reasons. The various types of vibration are
1. Free Vibration: This is a type of vibration which can neither be induced nor stopped. They tend to vibrate forever. Some good known example known to me is the movement of electrons.
2. Forced Vibration: This is a type of vibration occurs due to forcing of a system to vibrate. The vibration of the leaves or the movements of the leaves in the trees or plants are good examples. But they tend to be damped or stopped due to the systems nature.
3. Damped Vibration: This is a type of vibration where a forced vibration or a self induced vibration is damped or stopped from causing further inconvenience. A good example of this would be dampening of vibrations in the automobile using shock absorbers.
4. Random Vibration: These occur very rarely and randomly in nature. A good example for this would be the earthquake, with nothing to tell us really about its magnitude and nature. These vibrations are hence very difficult for controlling.