8.11.2. Phase vs Frequency Ratio

Try these first

1. 1.

   What does the phase angle represent?

   Hint

   Think about the relationship between input and output.

2. 2.

   What is the frequency ratio?

   Hint

   Recall how frequency is compared in systems.

3. 3.

   What happens to the phase angle at resonance?

   • 0°
   • 90°
   • 180°

   Hint

   Consider the implications of matching frequencies.

4. 4.

   True or False: Increasing damping decreases the phase lag in a harmonic system.

   • True
   • False

   Hint

   Damping plays a key role in phase relationships.

5. 5.

   A bridge experiences harmonic loading at a frequency ratio of 1.1. Calculate the likely phase angle. Discuss the implications of this phase shift.

   Hint

   Can you recall the phase angles corresponding to different frequency ratios?

6. 6.

   Design a dynamic absorber for a system with known natural frequency of 2 Hz intending to reduce vibrations at 2.2 Hz. Explain your design considerations.

   Hint

   Think about phase shifts and how they apply to countervailing harmonics.