Influence of rubber compressibility on the compressive stiffness of steel-reinforced elastomeric bearings in finite element simulations considering the shape factor
November 2022, Polymer Engineering and Science
Skender, Ana; Damjanović, Domagoj; Bartolac, Marko; Duvnjak, Ivan
University of Zagreb
Faculty of Civil Engineering
Structural Testing Laboratory
Abstract: In finite element analysis of steel-reinforced elastomeric bearings (SREB) under compression, modeling of rubber as a nearly or fully incompressible material requires special attention. In this study, finite element simulations of circular elastomeric pads and rectangular SREB under compression were performed to analyze the effects of rubber compressibility with respect to different pad geometries and shape factor values. The ratio of the compressive modulus for a compressible rubber to that of an incompressible rubber was also introduced based on the previously derived exact solutions as well as the ad hoc approximations. This ratio accurately represents the influence of compressibility on compressive stiffness in terms of relative compressibility (K/G) and shape factor values. Numerical results were also compared with the experimental results on rectangular SREB with moderate shape factors. Recommended values for relative compressibility of carbon black-filled rubbers in the range of 50–200 result in underestimated compressive stiffness, especially for bearings with shape factor values greater than five. It is recommended to adjust the relative compressibility, considering the shape factor, so that the compressive stiffness does not decrease by more than 50% compared to the incompressible case.