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 shea r deformation, but it does not consider the damping effect. In order to stu dy the behavior of isolation bearings which possess an energy-dissipation c apacity, the explicit formulas for the horizontal stiffness of viscoelastic columns and the corresponded height reduction are derived by the method of variable separation. These explicit formulas are then applied to develop a n identification procedure to find the shear modulus and loss factor of the rubber using the cyclic shear tests of isolation bearings. Through this id entification procedure, the empirical formulas for the shear modulus and th e loss factor of rubber are established as functions of the strain amplitud e and the excitation frequency. (C) 2000 Elsevier Science Ltd. All rights r eserved.