Hello Geovanna,

This website has a good explanation of the equations for simple harmonic motion.

If you start with a specification on the acceleration amplitude of 1G = 9810 mm/s^2, use the third set of equations that has the constant C for the amplitude.

In the example above, f = 30 Hz so w = 2*Pi*30 = 188.5 radians/sec.

The displacement amplitude is C/w^2 = 9810/188^2 = 0.276 mm.

In the description of your project, you mention the HP of the engine, and the RPM, but that doesn't help to define either an acceleration or a displacement base vibration amplitude that engine creates. The best way to know the base vibration amplitude that engine creates is to fasten an accelerometer to the base and record the vibration using a data acquisition system. I have experience with that instrumentation if you would like to discuss it further.