Separation and determination of combined dampings from free vibrations

An Approach to Parameter Identification for a Single-Degree-of-Freedom Dynamical System Based on Short Free Acceleration Response

“…model in which the free vibrations are governed by equation (1). This can be a "nal model or just a "rst approach to the problem.…”

“…2. Estimation of the parameters is achieved by a least-squares "t of the chi-squared merit function, equation (2), deduced from the equation of motion, equation (1). Since the equation of motion (1) is valid for any given time, the values of the equation for all the discrete times can be summed, and thus the merit function can be created as…”

“…One study [1] considered the free vibrations of a single-degree-of-freedom (s.d.o.f.) system with combined viscous damping and Coulomb dry friction.…”

Phase Portraits of the Autonomous Duffing Single-Degree-of-Freedom Oscillator with Coulomb Dry Friction

“…Both mechanisms of energy dissipation have been used in many studies concerning the forced system, for example, [7][8][9]. It was shown that separating the viscous damping and frictional damping from the system response is possible, but difficult [10,11]. Hence, the interactions between both mechanisms of energy dissipation should be well understood.…”