Experimental and finite element study on the compression properties of Modified Rectangular Fiber-Reinforced Elastomeric Isolators (MR-FREIs)

This study investigates the compressive behavior of Modified Rectangular Fiber-Reinforced Elastomeric Isolators (MR-FREIs). The geometric modifications are introduced to reduce the horizontal stiffness and increase the energy dissipation of the isolation system, allowing long rectangular isolators that provide uniform support along walls to be utilized. It is of critical importance that MR-FREIs maintain adequate vertical stiffness to satisfy the requirements for an isolation system. Experimental data from vertical tests of four rectangular FREIs with and without geometric modifications is used to evaluate a three-dimensional (3D) finite element (FE) model. The 3D FE model is then used to conduct a parametric study on two MR-FREI configurations with varying geometry. The parametric study investigates the effect of the geometric modifications on the vertical stiffness and compression modulus in addition to stress and strain distributions in the elastomer and fiber reinforcement. The study identifies that, similar to annular isolators, introducing a minor geometric modification to the interior of the isolator results in a significant decrease in vertical stiffness and compression modulus. This influence is considerably less for geometric modifications positioned on the exterior of the isolator.