Question:
Why is critical damping desirable in many engineering applications?
Answer:
All damped oscillations return to the equilibrium position eventually as the damping force saps energy continously from the oscillation. However, the manner in which the oscillations cease depends on the degree of damping.
If underdamped (aka light damping), the pendulum overshoots the equilibrium position and comes to rest only after a number of oscillations.
If critically-damped, the pendulum returns to the equilibrium position without overshooting the equilibrium position.
If overdamped (aka heavy damping), the pendulum does not overshoot the equilibrium position, but returns to the equilibrium position more slowly (compared to critical damping).
Did you notice that the critically-damped oscillation comes to rest at the equilibrium position most quickly? Watch the collage at the end of the video again if you don’t believe me.
In many engineering applications, oscillations are a nuisance at best and safety hazards at worst. For example, a car’s suspension system is set into oscillation whenever the car hits a hump on an uneven road (kind of like an inverted spring-mass system). If the oscillation is not removed quickly, the passengers are going to puke. Also, tall buildings are set into oscillation whenever the ground shakes due to reasons such earthquakes or heavy construction (kind of like an inverted pendulum). If the oscillation is not suppressed, the buildings may snap. In such scenarios, critical damping is desired so that the oscillations are removed in the shortest possible time.
xmPhysics 