Damping constant and angular frequency

The first one is more commonly used in textbooks and the second one is more commonly used in research papers. In summary, when discussing the angular frequency of a damped harmonic oscillator, the book states that if the damping constant b is small but not zero, and b is much smaller than the square root of the product of the springiness k and mass m, then the damped angular frequency ω^{'} is approximately equal to the undamped angular frequency ω. However, another expression, b \ll \sqrt{2km}, can also be used to represent this relationship. This difference in notation is not significant when discussing quantities that are much, much smaller than another.
  • #1
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While discussing [itex]ω^{'}[/itex], the angular frequency of a damped harmonic oscillator, given by:
[itex]ω^{'}=\sqrt{\frac{k}{m}-\frac{b^{2}}{4m^{2}}}[/itex]
where k is the "springiness", m is the mass, and b is the damping constant,
my book, Halliday, Resnick and Walker, says if b is small but not zero,[itex]b<<\sqrt{km}[/itex] then [itex]ω^{'}\approxω[/itex]. [itex]ω=\frac{k}{m}[/itex], the undamped frequency.

If I say that [itex]\frac{k}{m}>>\frac{b^{2}}{4m^{2}}[/itex]and go through the algebra to get the relation in the book, I get [itex]b<<\sqrt{2km}[/itex]
Is this a meaningful difference when talking about a quantity that is much, much less than another?
Thanks for any help.
 
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  • #2
The two statements, [itex]b \ll \sqrt{km} \text{ and } b \ll \sqrt{2km}[/itex], are essentially considered to be equivalent statements.
 

What is the relationship between damping constant and angular frequency?

The damping constant and angular frequency are related through the equation: damping constant = 2 * mass * angular frequency. This means that an increase in the damping constant will result in a decrease in the angular frequency, and vice versa.

What is the significance of the damping constant and angular frequency in a system?

The damping constant and angular frequency are important parameters in a system that experiences oscillation or vibration. They determine the rate at which the system's energy dissipates and how quickly the system returns to its equilibrium state.

How does the damping constant affect the behavior of a system?

The damping constant determines whether a system is underdamped, critically damped, or overdamped. Underdamped systems have a lower damping constant and exhibit oscillatory behavior, while overdamped systems have a higher damping constant and do not oscillate. Critically damped systems have a damping constant that results in the quickest return to equilibrium without oscillation.

What factors can affect the value of the damping constant and angular frequency in a system?

The damping constant can be affected by the type of material used in the system, the shape and size of the system, and any external forces acting on the system. The angular frequency is primarily determined by the stiffness of the system and the mass of the object experiencing oscillation.

How do engineers use the knowledge of damping constant and angular frequency in practical applications?

Engineers use the knowledge of damping constant and angular frequency to design and control systems that experience oscillation or vibration. By adjusting these parameters, engineers can optimize the performance and stability of a system, such as in car suspensions, buildings, and bridges.

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