3.3. Damping Ratio and Logarithmic Decrement

Try these first

1. 1.

   What is the damping ratio for an undamped system?

   Hint

   Think about the condition where no energy is lost.

2. 2.

   How does an underdamped system behave?

   Hint

   Consider how you would describe a swing slowing down.

3. 3.

   What is the damping ratio for a critically damped system?

   • 0
   • 1
   • >1
   • <1

   Hint

   Remember the definition of critically damped.

4. 4.

   True or False: Logarithmic decrement can only be calculated from experimental data.

   • True
   • False

   Hint

   Think about the formula; it relies on amplitudes.

5. 5.

   A building has a damping ratio of 0.1. Explain how you would advise an engineer about its design against seismic activity.

   Hint

   Consider the relationship between damping and safety.

6. 6.

   Given a system with a logarithmic decrement of 1.5, calculate the damping ratio and discuss its implications for structural design.

   Hint

   Remember the formulas when estimating damping.