Finite element analysis of elastomeric sliding isolator system (ESI)

Mozaheb, Seyed Alireza; Behnamfar, ّFarhad

doi:10.22065/jsce.2024.408072.3181

Finite element analysis of elastomeric sliding isolator system (ESI)

Document Type : Original Article

Authors

Seyed Alireza Mozaheb ¹

ّFarhad Behnamfar ²

¹ Department of Civil Engineering, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran.

² Professor, Department of Civil and Environment Engineering, Isfahan University of Technology, Isfahan, Iran

10.22065/jsce.2024.408072.3181

Abstract

This paper presents a new elastomeric sliding seismic isolator system. This isolator is made of a rubber core which is confined by sliding steel rings. In this system, the vertical load is applied directly on the rubber core. The friction mechanism existing in the mentioned system controls the lateral force due to winds, ambient vibrations and mild earthquakes, and also decreases transfer of lateral force to the superstructure during severe earthquakes. At the end of vibraion, the elasticity of rubber creates a restoring force and decreases residual deformation of the bearing device. Features of the proposed system are assessed by means of the finite element software ANSYS and the stress distribution of various components is obtained under compression and compression-shear loading. Contact elements were used to model the contact surfaces, and Solid185 elements were used to simulate the rubber. The studies show that an appropriate vertical and lateral stiffness is created by interaction of the steel rings and the elastomeric core. In addition, under vertical loading, all the stress components are far less than the allowable limit. Due to lateral movement, a part of the vertical load is transferred to the steel rings which not only de-escalates the stress at the rubber core, but also increases damping due to friction in the system. Steel rings effectively enhance the vertical stiffness of the system by controlling the lateral strains experienced by the rubber material. In the specific sample being examined, a vertical load of 100 kN leads to a vertical stiffness value of 131 kN/mm in the system. Under a vertical load of 100 kN, the stress values sx (along lateral displacement), sz, and sy in the rubber core, subjected to a 200% shear strain, were reduced by 25%, 50%, and 51%, respectively, compared to the scenario without lateral displacement.

Keywords

Sliding-elastomeric isolator

vertical and lateral stiffness

confined rubber core

frictional damping

finite element analysis

Subjects

Active and Passive Control of Structures

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