Transmissibility function given in Eq. (1) was derived for a SDOF system considering a massless isolator model. This assumption works well for low frequency vibrations, whereas it has led to significant problems at high frequencies. In reality, vibration isolators have mass therefore, specific vibration characteristics, thus, transmitted vibration may amplify due to isolator resonance frequencies [23], [44] and [45]. These frequencies are usually called as surge frequencies. Surge frequencies are mostly critical for steel spring type vibration isolators and can be estimated using Eq. (2).