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COBEM 2023
27th International Congress of Mechanical Engineering
THE APPLICATION OF MAGNETO-RHEOLOGICAL ELASTOMER IN A BASE INSOLATION SYSTEM FOR SEISMIC MITIGATION OF HIGHWAY BRIDGES
Submission Author:
Fernanda Almeida , SP
Co-Authors:
Fernanda Almeida, Matheus Proença, Henrique Edno Leoncini de Carvalho, Daniel Henrique de Sousa Obata, Jeferson Camargo Fukushima, Amarildo Tabone Paschoalini
Presenter: Fernanda Almeida
doi://10.26678/ABCM.COBEM2023.COB2023-1516
Abstract
In recent years, the implementation of damping systems in civil structures has gained considerable attention, with particular emphasis on special building projects. For instance, systems composed of intelligent materials are being developed and investigated to optimize the behavior of bridges structure under dynamic loadings. In this scenario, due to its mechanical simplicity and controllable properties, Magneto-Rheological Elastomer (MRE) has stood out as an interesting alternative for vibration isolation. In these materials, the magnetic particles present in the elastomeric matrix are easily polarized in the presence of an external magnetic source, generating non-linear and reversible changes in the material, within a few milliseconds. In this way, the present work investigated numerically the efficiency of a certain damping system with MRE in isolating vibrations at the base of a bridge superstructure. The elastomer pictured has a matrix consisting of white silicone rubber and carbonyl iron magnetic particles (Sigma > 97%). Its elastic and viscous properties were previously characterized in experimental tests for different stresses and magnetic fields. In the numerical implementations, the elastomer was simulated as a visco-elastic material of Kelvin-Voigt, and its stiffness and viscosity were regulated for five different scenarios. The unidimensional equivalent mechanical model was considered as a single-degree-of-freedom (SDOF) system, and the ground motion generated by seismic excitations corresponded to shear excitations at the base. The base-isolated tests provided acceleration transmissibility under the different applied magnetic fields. It was observed that the viscoelastic support (VS) was able to shift the resonance frequency and the attenuation of transmissibility peak efficiently through field control. Moreover, with an adequate approach in the frequency domain, the random signal of a real earthquake was also inserted into the system for the evaluation of the isolator material. The finds demonstrated the good performance of the proposed MRE and its possibility of seismic vibrations mitigation.
Keywords
Magnetorheological Elastomers, MRE, Vibration Isolator
