Strutt|Vibration|Isolation Design|Isolation Efficiency calculates the vibration isolation performance of a vibration isolator by modelling it as a lumped mass spring-mass-damper system
The force transmissibility ratio `TR` is calculated as:
`TR=sqrt((1 + (2 * zeta * (f/f_0)) ^ 2) / ((1 - (f/f_0) ^ 2) ^ 2 + (2 * zeta* (f/f_0)) ^ 2))`
where:
`zeta` is the damping ratio of the system
`f` is the input frequency
`f_0` is the natural frequency of the system
The isolation efficiency is calculated as `100*(1-TR)` (%)
Reference: Ogata, K (2004) System Dynamics, Fourth Edition, eq 9-14