Equivalent model and parameter analysis of non-packed particle damper

Abstract A non-packed particle damper (NPPD) is an advantageous passive damping device with a wide frequency band and good robustness. However, its damping mechanism remains unclear, and its application for controlling vibrations in civil engineering structures is being explored. By analysing the particle motion state, this paper proposes a double inertia mass equivalent model (DIMEM) to reflect the interaction between particles. The effect of inertia was introduced in the DIMEM to consider the rolling effect of particles on the damping performance of the NPPD. An electromagnetic vibration table test of a single-storey frame structure with an NPPD was designed and performed. The parameter determination method and applicability of the DIMEM were also evaluated based on experimental and theoretical analyses. Furthermore, the effects of the parameters on the damping performance of the NPPD were systematically analysed. The results confirm that the equivalent model can reflect the damping performance and mechanism of the NPPD. The particle group inertia is an inherent property of the NPPD. With an increase in the ratio of inertance to particle mass, the optimal vibration damping performance deteriorates under harmonic excitation, and the corresponding equivalent connection stiffness gradually increases. The equivalent connection stiffness, additional mass ratio, recovery coefficient, and acceleration normalised collision distance significantly affect the damping performance and mechanism. However, the effects of the equivalent connection damping coefficient and rolling friction coefficient are negligible. The proposed DIMEM and the corresponding parameter analysis can provide an important reference for the application of NPPDs in civil engineering.