When we think about means to reduce vibration, we most often think in terms of vibration dampers, devices that convert vibratory energy into heat and thus reduce the vibrational motion. Fluid dampers, using various fluids, have been constructed for many applications, and while they work quite well, it is often necessary to provide for the removal of the heat generated in them.
There is an alternative to dampers, a different class of devices known as absorbers. The idea of an absorber is to briefly absorb the vibrational energy, and then to feed it back to the system but out of phase in such a way as to cancel the motion. Thus the absorber itself is often subject to large motions as it is absorbing, and then reinjecting energy into the system.
The name commonly associated with absorber systems if that of Frahm, a German. For an application of a Frahm absorber in an actual industrial situation, see the attached PDF file.
