Optimal Design of Inertial Amplifier Base Isolators for Dynamic Response Control of Multi-Storey Buildings

Abstract

The optimal design of inertial amplifier base isolators (IABI) for dynamic response mitigation of multi-storey buildings subjected to base excitations has been studied in this paper. In order to achieve the closed-form expressions for optimal design parameters of IABI, [Formula: see text] optimization method has been employed. The effectiveness of the closed-form expressions for optimal design parameters was evaluated by determining the isolated structures’ frequency and time domain responses and comparing them to the corresponding responses obtained from equivalent uncontrolled structures. A numerical study employing the Newmark-beta method is conducted to obtain time-domain responses using near-field earthquake base excitation. The response reduction capacity (%) of the optimum inertial amplifier base isolator is compared to the response reduction capacity (%) of the optimum traditional base isolators, demonstrating that inertial amplifiers have increased the vibration reduction performance of traditional base isolators by 50% to 60%. All the outcomes from the study are mathematically accurate and also feasible for practical design purposes.

The optimum enhanced viscoelastic tuned mass dampers: Exact closed-form expressions

“…The inertial amplifiers (Frandsen et al, 2016) have been applied to the conventional base isolators and conventional TMD to increase their vibration reduction capacities without affecting the static mass of the entire system (Chowdhury et al, 2022b, 2023b), like inerters with different mass amplification mechanisms (Chowdhury et al, 2021, 2022b). These inertial amplifier-inspired passive vibration control devices (Chowdhury et al, 2022a) are installed in the single and multi-degree of freedom systems to mitigate the dynamic responses during vibratory situations (Chowdhury et al, 2022a, 2023a; Chowdhury and Banerjee, 2022b]. Apart from the different structural configurations for enhancement of the vibration reduction performance, from the material perspective, the viscoelastic materials can also be applied to the traditional tuned mass damper to improve their dynamic response capacity (Batou and Adhikari, 2019).…”

The exact closed-form equations for optimal design parameters of enhanced inerter-based isolation systems

“…In the field of metamaterials, analogous combinations of negative stiffness with inertial amplifiers have also been acknowledged [Banerjee et al (2021); Dwivedi et al (2020); Yuksel and Yilmaz (2020)]. On the other hand, tuned mass dampers [Tsai (1995)], tuned mass damper inerters [De Domenico and Ricciardi (2018)], negative stiffness inertial amplifier tuned mass dampers Chowdhury et al (2022b), and tuned inerter dampers [De Domenico et al (2018)] are generally utilized in hybrid mode at the structural level to improve the performance of the base isolators [Adhikari and Banerjee (2021); Banerjee et al (2019); Chowdhury et al (2021); Chowdhury et al (2022a), (2022c)]. However, state-of-the-art on the base-isolation system may not incorporate neither the use of an enhanced inerter at the base isolator level to improve overall vibration reduction capability nor provided rigorous explicit analytical closed-form equations for optimal design parameters for its design.…”