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Study on “Valley” Phenomenon of Vibration Frequency Response Curve Based on Free Damping Structure

When studying the vibration suppression effect of the free damper beam, it is found that the frequency response curve shows a distinct “valley” at a specific frequency, showing a sudden drop in response at this frequency, which is similar to the “band gap” phenomenon in phononic crystals, which is inconsistent with general experience. Starting from the damping energy dissipation and the vibration of the damping layer itself, this paper draws the conclusion that the “valley” is caused by the resonance of the damping layer at a specific frequency and the dissipation of a large amount of energy, which makes the frequency response curve of the base beam “valley”, and then this paper analyses the influence of the geometrical and material parameters of the damping layer on the “valley” frequency and the “valley” value. In addition, the vibration response experiment of the free-damped beam is carried out, and the results are in good agreement with the simulation results, which verifies the correctness of the theoretical analysis.