An assessment of damping identification methods

A study is carried out into the philosophy and performance of different approaches for the determination of linear viscous damping in elasto-mechanical systems. The methods studied include a closed-form solution, identification methods based on inverting the matrix of receptances, energy expressions developed from single-frequency excitation and responses as well as first-order perturbation methods. The work is concentrated particularly upon modal truncation and how this affects the distribution of matrix terms and the ability of the identified damping (together with known mass and stiffness terms) to reproduce the complex eigenvalues and eigenvectors of the full-order system. A simulated example is used to illustrate various points covered in the theoretical discussion of the methods considered.