Modeling frictional heating effects in triple friction pendulum isolators

This paper augments the series spring model for Triple Friction Pendulum (TFP) isolators to predict the relative displacement and velocity at each of its four sliding interfaces. This enables the prediction of the rise in temperature at each sliding interface that results from frictional heating and the introduction of temperature-dependent friction coefficient. Moreover, the model directly accounts for the velocity-dependence of the friction coefficient as it can predict the actual velocities at each sliding interface, whereas the original series model only approximately accounted for the velocity effects. It also accounts for the effects of instantaneous bearing pressure on the friction coefficient. The model has been implemented in program OpenSees and has been verified by comparison to results obtained using a much more advanced and complex model that is unsuitable for computations with a large number of isolators.