I have had a look through the forum and don't think this topic has been covered before but would like to try and get some advice / opinions on modelling to equipment which is mounted on anti vibration mounts.

It has been suggested that the stiffness should be obtained from the equipment manufacturer and then modeled as springs. I can see that point of view but that would not give any information regarding the equipment displacement or amplitude.

Any opinions would be appreciated

Presumably the mounts are put in place at the recommendation / direction of the vibrating equipment manufacturer, and they should also be able to provide the response frequency and amplitude.

Presumably your pipe routing is not so restrictive that it impairs the anti-vibration mounts.