Abstract: Now a days, the vibration causes rapid wear of machine parts such as bearings and gears. Most common causes of machine vibration is wear, looseness, misalignment /shaft runout, imbalance then need of the day is producing noiseless and vibration free devices. Unwanted vibrations may cause loosening of parts from the machine. Because of improper design or material distribution, the wheels of locomotive can leave the track due to excessive vibration which results in accident or heavy loss. Sometimes because of heavy vibrations proper readings of instrument cannot be taken. Also some time machine will be destroys but some time vibration can be used for useful purposes such as vibration testing equipment's, vibratory conveyors, hoppers, and comparators. Vibration is found to be very fruitful in mechanical workshops such as improving the efficiency of machining, casting, forging and welding techniques. The transfer of noise can also be reduced by decoupling the components in such a way that the noise path is interrupted. This can be achieved by adding noise reducing treatments to the structure such as elastic elements, masses, local shielding or damping layers. In the present investigation, the use of viscoelastic damping layers as a noise reducing measure in rotating machinery is considered. Here in this investigation the result obtained will give frequency value in random manner and the use of testing hypothesis will show us that vibrations are really reduced or not.

Keywords: Fast Fourier Transform (FFT analyser), T-TEST(Statistical Test), Viscoelastic Material, Vibration Reduction.