Damping identification in multiple degree-of-freedom systems using an energy balance approach

The dissipation of energy in a vibrating structure is often neglected or oversimplified in engineering design. However, there are many cases where an accurate model of damping is necessary and an effective identification is required in order to predict instabilities or unwanted vibrations of the system. The paper presents a method which balances the energy input by a sinusoidal force with the energy dissipated by damping mechanisms in order to locate and identify damping. If a complete set of measurements is available, there is no need to know or to evaluate the mass and stiffness matrices and the only data needed are the time histories of the response of the structure excited with a set of single-frequency harmonic excitations. The method has been validated by numerical simulations and tested on a real structure, a clamped aluminium beam with a magnetic eddy current dashpot.