Resonance of damping

Considered is a linear forced vibrating structure (primary structure) to which another linear passive structure (absorber) is attached at a number of points. It is shown analytically that the vibration power flow from the primary structure to the absorber reaches its absolute maximum if two conditions are met simultaneously. The first condition is well known: there must be a frequency resonance when the forcing frequency coincides with one of the eigen frequencies of the primary structure/absorber system. The second condition is also of the resonant type: at the frequency resonance vibration mode, the amount of damping in the absorber must be equal to the amount of damping in the primary structure. This can be called the resonance of damping. The vibration or sound absorber that satisfies both resonance conditions can be called the best or the perfect absorber. The theoretical result obtained has been verified in a laboratory experiment with a simple primary structure and a dynamic vibration absorber as well as in an impedance tube on a resonant sound absorber. Relation to results known from the literature and possible applications using metamaterials are discussed.