In vibration isolation, which one of the following statements is NOT correct regarding Transmissibility (T)?
T can be always reduced by using higher damping at any excitation frequency
Increasing damping reduces the resonance peak but increases transmissibility in the isolation region above frequency ratio √2. Thus higher damping does not always reduce T. T tends to 1 at low frequency, equals 1 at √2, and is unbounded at undamped resonance.
Important Questions from Transmissibility and Magnification Factor
When ω/ωn = 1, the transmissibility is
where ω = frequency of excitation, rad/s
ωn = Natural frequency, rad/s
The Transmissibility of a vibrating system, for the values of (ω/ωn) >√2, will be
A vibrating system having a mass of 30 kg is supported by 4 springs, each having a stiffness of k. The system runs at 420 rpm. If only 10% of the shaking force is allowed to be transmitted to the supporting structure, then the value of stiffness k will be close to:
For a single degree of freedom viscous damped system, if the frequency ratio is greater than √2, it implies that:
Dynamic Magnification Factor is computed as:
