Accurate Measurement of Effective Dynamic Load of Equipment Transmitted to the Floor

How does one accurately measure the effective dynamic load in frequency domain exerted by heavy equipment (huge vacuum pump, multistage centrifugal pump, and etc.) transmitted to arbitrary floor without reallocating the equipment?

One method I can think of is to work out the FRF of the floor at a point close to equipment foundation with a force hammer when the equipment is in rest and capture the floor response when the machine is operating. The dynamic load can be then be determined by the relationship of input and output. According to theory it should work for cases with single-toned harmonic excitation, however the equipment is expected to emit multi-toned or non-harmonic excitation.

Is there any other established method to deal with this kind of problem?

Is there a sweet spot on the equipment where its acceleration can give us a good approximation of dynamic force generated?


I too am not aware of any established method to deal with this type of problem.

If your equipment is on isolators, you could measured the motion above and below the isolators, the difference multiplied by the stiffness gets you vertical transmitted force. The catch is you know what the stiffness is at that particular pre-load and the isolator is linear enough to make that assumption.

Depending on your floor, measuring transfer function of the floor could be difficult as the acceleration levels could be very low (seismic accelerometers?).

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