Damped Oscillations
Forced oscillator with damping resistance force is proportional to speed : Equation of motion
For convenience: Also, k=mw02 In ‘complex’ method
Solution of damped harmonic motion Define
Maximum amplitude at
or
-q SB
Damped oscillation movie © Walter Fendt (2006) http://www.walter-fendt.de/ph14e/springpendulum.htm
Average energy of the oscillator
Plot of r2 vs w (near resonance)
Work done by the force per second Power
Stored Energy
Mean power
Mean stored energy
Efficiency of the oscillator Stored energy in oscillator Work done by force per cycle
Another measure of response Q factor
Summary Damped forced oscillation Effect of damping is negligible at low and high frequency regime Effect of damping is large near resonance Increase in width and shift in resonance frequency with an increase in damping