Modeling of the temperature rises in multiple friction pendulum bearings by means of thermomechanical rheological elements

Even if the effectiveness of friction pendulum bearings has been extensively proven by means of numerous experimental programs carried out worldwide, many aspects concerning their behavior under seismic action still need to be clarified. One of these is related to the temperature rises induced by the heat generated by friction during the dynamic sliding of the surfaces in contact, which may significantly affect the superficial frictional properties of the sliding surfaces involved, thus reducing the overall performance of the isolating system, up to re-coupling the structure with the ground shaking, in a limit scenario. With the aim to contribute to a better understanding of this aspect, and to develop a simplified tool capable to reproduce the hysteretic force–displacement loops together with the corresponding temperature variations, a thermo-mechanical model for the multiple friction pendulum devices is proposed. The model is based on the combination of simple thermomechanical rheological elements and does not require the evaluation of any convolution integral arising from the solution of the heat conduction problem as it happens with many existing models. The model is numerically implemented under displacement-control and its effectiveness is validated through the numerical simulation of some recent experimental results that shows a good agreement with the observed behavior.