A mathematical hysteretic model for elastomeric isolation bearings

Abstract

SUMMARYAn analytical model for high damping elastomeric isolation bearings is presented in this paper. The model is used to describe mathematically the damping force and restoring force of the rubber material and bearing. Ten parameters to be identiÿed from cyclic loading tests are included in the model. The sensitivity of the ten parameters in a ecting the model is examined. These ten parameters are functions of a number of in uence factors on the elastomer such as the rubber compound, Mullins e ect, scragging e ect, frequency, temperature and axial load. In this study, however, only the Mullins e ect, scragging e ect, frequency and temperature are investigated. Both material tests and shaking table tests were performed to validate the proposed model. Based on the comparison between the experimental and the analytical results, it is found that the proposed analytical model is capable of predicting the shear force-displacement hysteresis very accurately for both rubber material and bearing under cyclic loading reversals. The seismic response time histories of the bearing can also be captured, using the proposed analytical model, with a practically acceptable precision.

Dynamic systems with high damping rubber: Nonlinear behaviour and linear approximation

“…Thus, the method proposed by Hwang et al [12], Yoshida et al [13] and Hwang and Ku [14] and accepted by technical codes [16][17][18] provides results that are close to the method proposed by the authors for the stationary response. The only significant approximation introduced is due to the difference of periods between the nonlinear system and the equivalent linear system.…”

“…Papers that aim at describing the seismic behaviour of HDR devices usually propose constitutive laws based on simple models modified to take into account the strongly nonlinear strain dependence and the strain rate dependence [10][11][12]. Few works have attempted to model even the process-dependent behaviour [13].…”

Mechanical Characterization of Laminated Rubber Bearings and Their Modeling Approach"

“…In this regard, the works of Dall'Asta and Ragni [18]; Hwang et al [19] and Tsai et al [20] can be reported. They studied the mechanical behavior of high damping rubber dissipating devices by conducting different experiments such as sinusoidal loading tests at different frequencies, simple cyclic shear tests at different strain-rates along with relaxation tests.…”

“…The general mechanical behavior of laminated rubber bearings mainly concerns with nonlinear rate-dependent hysteretic property [18,19] in addition to other inelastic behavior like Mullin's softening effect [30] and relaxation behavior [31]. All these characteristic behaviors generally originate from the molecular structures of the strength elements of rubber materials used in manufacturing of the bearings.…”

Studying the standard's requirements for elastomeric seismic isolators by virtual testing

“…For representation of variation of isolator's stiffness at repeating cycles due to scragging [16][17][18], the following dependence is accepted in Simulink models:…”