Mechanical properties of isolation bearings identified by a viscoelastic model

The Haringx theory is usually employed to describe the mechanical behavior of rubber bearings subjected to a compressive axial load and a lateral shear deformation, but it does not consider the damping e€ect. In order to study the behavior of isolation bearings which possess an energy-dissipation capacity, the explicit formulas for the horizontal sti€ness of viscoelastic columns and the corresponded height reduction are derived by the method of variable separation. These explicit formulas are then applied to develop an identi®cation procedure to ®nd the shear modulus and loss factor of the rubber using the cyclic shear tests of isolation bearings. Through this identi®cation procedure, the empirical formulas for the shear modulus and the loss factor of rubber are established as functions of the strain amplitude and the excitation frequency