An alternative method to the identification of the modal damping factor based on the dissipated energy

• A new method for the identification of the modal damping factor is presented.
• The starting point is the dissipated energy per vibration cycle.
• Identification is made directly from measured Frequency Response Functions.
• It is a simple and easy to implement method.
• It is accurate for lightly damped structures with spaced mode shapes.

The identification of the modal parameters from frequency response functions is a subject that is not new. However, the starting point often comes from the equations that govern the dynamic motion. In this paper, a novel approach is shown, resulting from an analysis that starts on the dissipated energy per cycle of vibration. Numerical and experimental examples were used in order to assess the effectiveness of the proposed method. It was shown that, for lightly damped systems with conveniently spaced modes, it produced quite accurate results when compared to those obtained from the method of the inverse. The technique also proved to be simple enough to be used for quick estimates of the modal damping factors. Finally, this paper is a contribution to modal analysis and identification methods, as the developed technique has never been proposed before.