Influence analysis of parameters of thermal aging laminated rubber bearing under cyclic shear loads

Abstract

Composite rubber bearing is an important supporting component in bridge structure system, its aging and shear performance will affect the safety of the whole structure. However, due to the complexity of LRB specifications and sizes, the shear properties of aging LRB under different parameters were studied. In this study, the thermal aging and shear tests of 12 LRBs of the same specifications were first carried out, and the test results were taken as a reference, and the finite element model was established to select the constitutive model and determine the parameters, and finally the constitutive model and parameters consistent with the test were determined. Then, LRBs with different shape coefficient, diameter and number of layers were established, and shear simulation was carried out respectively to compare with the shear performance of the test supports, and the changes of parameters such as maximum shear force, energy dissipation, equivalent shear stiffness, initial sliding displacement and sliding distance generated by LRBs of different specifications at different shear stages were studied. The results show that for LRB of the same specifications, aging does not affect the maximum shear force, but the hardness and energy dissipation of rubber material increase with the aging time, and the initial sliding distance decreases with the aging time. For LRB with different parameters, under the same aging time, the maximum shear force and energy dissipation increase with the increase of shear deformation, and the equivalent shear stiffness decreases with the increase of shear degree. The maximum shear force, energy dissipation and initial shear stiffness of LRB increase with the increase of shape coefficient and diameter. The number of layers of the LRB does not affect the maximum shear force, but the energy dissipation increases with the increase of the number of layers, and the equivalent shear stiffness decreases with the increase of the number of layers. The larger the shape factor, diameter and layer number of LRB, the more likely it is to slip. Therefore, the influence of bearing parameters on the shear performance of LRB should be considered comprehensively when designing LRB in actual engineering.