Variable friction-tuned viscous mass damper and power-flow-based control

The passive tuned viscous mass damper (TVMD), i.e., a classic inerter system, has been proven as an efficient vibration mitigation device that is characterized by a damping-enhancement effect for enhanced energy absorption and dissipation. However, due to the sensitivity of the tuning frequency, the effective frequency band of TVMD for vibration reduction is limited, so that the enhanced energy absorption and dissipation are limited. Dealing with this, this study proposes a novel variable friction TVMD (VF-TVMD) by incorporating a sub-device with variable friction forces into the TVMD, successively maximizing the energy dissipation efficiency of VF-TVMD by employing a power-flow-based algorithm. A power-flow analysis is performed for TVMD-structures, which explicitly determine the optimal phase deviation of the dashpot-deformation in TVMD with respect to structural displacement. Given this finding, the friction device in VF-TVMD is employed by the proposed power-flow-based control strategy to adjust the asynchronous vibration between the TVMD and primary structure. Through the implementation of VF-TVMD, the feasibility and effectiveness are illustrated by numerical examples. The results show that a desired phase lag of the TVMD with respect to the structure is -90 degrees to guarantee TVMD the maximum power flow for energy dissipation. Benefitting from the variable friction force, the VF-TVMD is more effective for structural vibration control and exhibits a more significant damping-enhancement effect, in comparison with the TVMD. Applicable in a wider frequency band, the structural vibration can be significantly mitigated by the optimized VF-TVMD or even by VF-TVMD with un-optimized stiffness and damping ratios.

Automated summary

This study introduces a novel variable friction TVMD system, which effectively addresses the limitations of traditional TVMD systems in vibration reduction. Through power-flow analysis and control strategy, the energy dissipation efficiency of VF-TVMD is successfully maximized. Numerical examples demonstrate that the VF-TVMD system has better control effectiveness and damping-enhancement effect.