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Frequency response analysis of vibration system with parametric excitation of damping coefficient

This paper proposes a new method for the frequency response analysis of a vibration system with parametric excitation of damping coefficient. A base-excited single-degree-of-freedom model with a variable damper is considered. The variable damping coefficient can be changed to that in the case of a sine wave, i.e., a parametric excitation whose frequency can be arbitrarily selected. One of the external forces acting on the mass through the damper from the base is equivalent to the product of the damping coefficient and the input velocity. The product of the input sine wave and the frequency-controlled sine wave for variable damping, yields a new vibration that has a frequency different from the input frequency. Therefore, the oscillation of the damping coefficient at a suitable frequency can generate a new vibrational component that has the same frequency as that of the eigen-oscillation of the vibration system. As a result, the vibration amplitude increases because of resonance. In this study, first, we carry out theoretical analysis and obtain the frequency response of the proposed system. Subsequently, we confirm the effectiveness of the proposed analysis method by comparing the analysis result with previous simulation results.