Topic: Mechanical Vibrations
In a vibration isolation system, the transmissibility will be less than unity for all values of damping factors, if the ratio of forcing frequency to natural frequency is
- A. equal to 1
- B. less than $\sqrt{2}$
- C. more than $\sqrt{2}$
- D. equal to 2
Answer: C. more than $\sqrt{2}$
Explanation: Transmissibility ratio ($T_r$) is the ratio of force transmitted to the foundation to the force applied. $T_r < 1$ ensures vibration isolation. By analyzing the transmissibility curve, $T_r$ is less than 1 for all values of the damping ratio $\zeta$ only when the frequency ratio $\frac{\omega}{\omega_n} > \sqrt{2}$.