Vibration Isolation on Rigid and Nonrigid Foundations.

The problem of isolating machinery vibration from rigid and nonrigid substructures is analyzed in detail. The nonrigid substructures are modeled by clamped-clamped beams and by simply supported plates with small internal damping of the solid type. Both simple and compound mounting systems are analyzed. The advantages that result from the use of the compound mounting system are clearly apparent. The loss in isolation is described that results when nonrigid flanges or feet support the simply mounted item or the intermediate mass of the compound mounting system. The use is also analyzed of dynamic vibration absorbers or lumped masses to load the beamlike and platelike substructures at each mount location. The item of machinery is supported either by eight or by four antivibration mounts that have small damping of the solid type. It is shown how the number of beam and plate resonances that are excited can be reduced by judicious placement of the antivibration mountings. Author