Dynamic analysis and response attenuation of a two-degree-of-freedom structure with a variable inertia rotational mechanism subjected to ground excitation

Rotational inertia mechanisms offer innovative possibilities for mitigating the effects of dynamic loads on structures. While conventional approaches to structural response modification involve modifying stiffness, strength and damping, a promising alternative lies in the variable inertia rotational mechanism (VIRM), which represents a novel approach for variably shifting the effective mass of a structure. Despite its potential, the vibration mitigation effectiveness of the VIRM under seismic loads and its influence on frequency shifts with complex loading environments remain a gap in current understanding. This study explores the impact of the VIRM on a two-degree-of-freedom (2DOF) structure subjected to white noise loading and seismic ground motions. Through a numerical assessment of this structure with single and multiple VIRMs and considering different inertance ratios and load amplitudes, this study seeks to investigate the frequency shifts and the efficacy of VIRM in reducing structural response. The findings of this study highlight the potential of VIRM’s to alter natural frequencies and mitigate structural response under different load scenarios. This study addresses existing gaps in knowledge and contributes valuable insights into the interplay of VIRM parameters, frequency shifts, and the effectiveness of VIRMs for enhancing structural performance and seismic protection. •Passive control device investigated is variable inertia rotational mechanism (VIRM).•VIRM’s impact on a multi-degree-of-freedom structure is explored.•The study analyzes VIRM’s effect on modes and compares with fixed inertia devices.•Numerical assessment revealed VIRM's potential in altering natural frequencies.•Enhanced performance in story drift mitigation with higher flywheel mass ratios.