Tensile load-carrying behaviour of elastomeric bearings

Elastomeric bearings for seismic isolation applications can be subjected to tensile loads depending on the geometrical configuration, high vertical seismic motion or excessive horizontal deformation due to the elongated-period horizontal motion. It is a known fact that cavities develop within elastomeric material when it undergoes a certain amount of tensile force in a very constrained condition since a high hydrostatic tensile stress builds up. Once these cavities have developed, the tensile stiffness of the bearing drops dramatically. This paper contributes to understanding this phenomenon itself and its influence on the basic properties of elastomeric bearings. For this purpose, two types of elastomeric bearing were tested and the cavitation phenomenon observed. Moreover, those test results are compared with the FE simulation results from the modified hyperelastic material model with the cavity damage criterion. The two-phase softening model presented here can simulate the real softening behaviour of elastomeric bearings well, and it may even help us grasp a better insight into the cavitation phenomenon.