Michael's observation is true. Whenever, a vibration happens at the site, a stress engineer is the first one who is always called upon even without proper root cause analysis.

I believe, it's always a good start to find the root cause before anything is done on the piping side.

Solving the vibration problem is a complex task. Giving it to a consultant who has vast experience in solving problems of this kind would be advisable.

Sometimes the solution is a trial and error, and it's hard to guarantee to a client that after giving the recommendation the vibration will reach its acceptable level.

As a start, you can request the vibration levels at critical points (displacement/velocity vs. frequency) and compare them to industry guidelines. Normally, it will show above the limits if severe vibration is observed.

Secondly, you can model the vibration characteristics of the piping system by performing the modal analysis (making sure that the boundary condition is as accurate as possible). In the end, you will want to avoid resonance by keeping the natural frequency of the piping system away from the excitation frequency (+/- 20%).

Another tool is performing harmonic analysis to check the stress levels at critical points. But normally, harmonic analysis will have a dramatic effect if the two frequencies are very near each other (in which amplification of vibration occurs).

If you are preparing a report, make sure that you cover all your basis. In the end, it is difficult to define the excitation frequency as it can be broadband, in which even if you increase the frequency of the piping, it may happen that it will coincide with the excitation frequency which does not occur currently (but it is just there in the system waiting to be excited).

So yes, there is no straightforward answer to a vibration problem as you need to establish firmly the source of excitation.

As a saying goes, prevention is always better than cure.

But in this case, since the problem is already there, something needs to be done anyway.

Cheers!!