Presenting the Potential of Optimum Torsionally Coupled Base Isolators for Vibration Control of Torsionally Coupled Structures: Exact Closed-Form Expressions

Abstract

This paper explores the potential of optimum torsionally coupled base isolators for the vibration control of torsionally coupled structures. Newton’s second law is used to derive the governing equations of motion, and the H2 optimization method is used to derive the optimal design parameters. The frequency response function is formed to analyze the dynamic responses of the torsionally coupled isolated structures. Time history analysis is performed to validate the accuracy of the optimized design parameters. The Newmark-beta method is used to solve the governing equations of motion. The study found that a higher value of isolator mass and eccentricity ratios is recommended for optimal design. The dynamic reduction capacity of the isolator of this study is significantly higher than the conventional isolator, with a displacement reduction capacity of 24.80% and an acceleration reduction capacity of 42.02%. The load-bearing capacity of the isolator is maintained, and a higher eccentricity value can generate torsion significantly. This is essential for a cost-effective design and enhances the load-bearing capacity of the isolator. This paper looks into how optimum torsionally coupled base isolators can control vibrations in a single degree of freedom, a conceptualized model of buildings, bridges, and other public safety-related structures. Newton’s second law is used to find the governing equations of motion, and the H2 optimization method is used to find the optimal design parameters. It is possible to look at the dynamic responses of single-degree-of-freedom systems by making the frequency response function. Time history analysis is further used by considering real earthquake excitations to make sure that the optimized design parameters are correct. The Newmark-beta method is applied for the time history analysis. The study found that for the optimal design, the isolator mass and eccentricity ratios should be higher. The optimum isolator has a much higher dynamic reduction capacity than a normal isolator. It can reduce displacement by 24.80% and acceleration by 42.02%. The isolator’s load-bearing capacity stays the same, and a higher eccentricity value can make torsion happen in a big way. For a design to be cost effective, this must be done. It also makes the isolator stronger.