hi.I am trying practically to measure the damping coefficient required for steady operation.Plz help what method I can use to measure the damping coefficient.I have already measured the spring constant for the material.
Assuming it's a "nice" material with a near-constant spring constant, you should be able to just set it vibrating and measure the natural decay of the vibration amplitude...you can back out the damping coefficient from that data.
Don't measure the time it takes to settle, just get a plot (table, whatever) of the positition vs. time for the naturally vibrating system. Or, you can do a forced vibration and measure the phase and amplitude difference between the forcing function and the actual position.
Either way, from that data you can determine the constants in the position vs. time differential equation for simple harmonic motion (see
for a reasonable introduction).
Once you know the constants, you can calculate the damping coefficient.