MODAL MASS, STIFFNESS AND DAMPING

For classically damped structures, modal mass, stiffness and damping can be defined directly from formulas that relate the full mass, stiffness and damping matrices to the transfer function matrix. The modal mass, stiffness, and damping definitions are derived in a previous paper [1], and are restated here for convenience. The transfer function is defined over the complex Laplace plane, as a function of the variable ) j s ( ω + σ = . Experimentally, the values of a transfer function are measured only along the ω j -axis in the s-plane, that is for ) j s ( ω = . These values are referred to as the Frequency Response Function (FRF).