Rubber-layer roller bearings (RLRB) for base isolation: The non-linear dynamic behavior

We focus this study on the dynamics of a Rubber-Layer Roller Bearing (RLRB) for vibrational base isolation. By exploiting viscoelastic friction arising from rigid cylinders rolling on concave rigid plates padded with rubber layers, the device is able to provide a nonlinear damping behavior. Specifically, we consider the case of a two degrees of freedom system, in which an inertial mass is base-isolated from ground motion by mean of RLRB. We firstly investigate the system dynamic response under sinusoidal ground motion, then we focus on a real earthquake excitation. In both cases, the system equipped with nonlinear RLRB device presents smaller inertial load and displacement compared to the case of a system exploiting linear damping. Further, we show that an optimization can be performed on the physical parameters of the device (i.e. the viscoelastic material relaxation time and the cylinders spacing) in order to further enhance the system dynamic behavior.