Numerical modeling of elastomeric seismic isolators for determining force–displacement curve from cyclic loading

Abstract

The ideal performance of seismic isolating systems during the past earthquakes has proved them to be very useful in protecting structures against earthquakes. The cyclic loading experimental tests are an important part in the process of completing the design of the isolators, yet they are very expensive and time consuming. Using the accurate analytical modeling of hysteresis tests and knowing the limitations and the amount of error of the finite elements model and its effect on designing the isolated structure make it possible to reduce the financial and time expenses involved in designing seismic isolators along with experimental tests. In the present study, the cyclic loading of two different isolating systems, namely, the high damping rubber bearing (HDRB) and lead rubber bearing (LRB) have been modeled and analyzed in ABAQUS and the outcomes were compared with the experimental results attained by other researchers. Regarding the fact that the most important and complicated component of the elastomeric isolating system is rubber, it was modeled using various strain energy functions. Other factors affecting the finite elements models of elastomeric isolators were also studied. After comparing the effective stiffness of the experimental sample with the analytical model of HDRB, the Yeoh function had the best performance in determining the effective stiffness of the isolating system with an error of less than 7%. In studying LRBs, too, three types of bearings with different dimensions and lateral strain values were studied; the polynomial function in shear strain value of 150% had the best performance in estimating effective stiffness and damping with errors of less than 3% and 18%, respectively.

Analysis of the seismic response of an RC frame structure with lead rubber bearings

“…It has been confirmed that the lead core provides an adequate level of energy dissipation [4,[10][11][12][13]. The numerical models for the analysis of the properties of a LRB were also developed [12,[14][15][16][17]. The seismic analysis of base isolated structures confirmed that the use of LRB has a favourable effect on the structural response [18][19][20].…”

Advancements in base isolation for seismic mitigation: Perspectives on elastomeric and lead rubber bearings

“…These values are crucial for numerical analysis of the rubber hyper elastic properties. [114][115][116][117] 𝑈 = µ{ The strain energy function for the Marlow form are as follows:…”

Development of Rectangular Vibration Isolators with Double Core Systems for Structures

“…Inserting a lead material into an isolation system is meant to give the hysteresis curve an elastic perfectly plastic behaviour [8]. The stress of lead material reaches the yield point under cyclic shear force at low tension stresses of 10 MPa and demonstrates a stable hysteric behaviour due to repeated yields under cyclic load [19]. The parameters of the lead material used in this study are listed in Table 3.…”

“…Isotropic, elastic, isothermal, and incompressible behaviour can be used to model such materials. The time and loading frequency have no effect on their behaviour during the test [19]. The ABAQUS software [27] has a number of hyperelastic material types, each of which defines the strain energy function differently.…”

“…The maximum mean displacements of the mass and shear centre at each level are then described as structural responses (Figs. 19,20). As shown in Fig.…”