A multi-layer thermo-mechanical coupling hysteretic model for high damping rubber bearings at low temperature

High damping rubber (HDR) bearings have been widely applied in seismic isolation of structures. However, the complex behavior of HDR bearings is influenced by thermal mechanism coupled with the seismic response of the structure, particularly at low ambient temperatures. In order to express the hysteretic restoring force behavior of HDR bearings involving temperature dependence, heating effect, and heat transfer with an improved accuracy, a multi-layer thermo-mechanical coupling model was developed. The thermal mechanism was illustrated by considering the heating effect and heat transfer in the multi-layer thermal-coupled model. A nonlinear hysteretic model including the temperature dependence of the stress-strain relationship of rubber was incorporated. Quasi-static cyclic loading was conducted for parameter identification and real-time hybrid simulation tests were carried out for model validation. The model accurately represented the time-dependent thermal mechanism within the bearing, considering the non-uniform distribution of internal temperature. Numerical results exhibited good agreement with the experimental results, including the hysteresis curve, temperature history, and temperature distribution. The model demonstrated improved accuracy in computing the hysteretic behavior compared with an existing simple model.