Rheometric, transient, and cyclic tests to assess the viscoelastic behavior of natural rubber-based compounds used for rubber bearings

Abstract

The damping capacity of rubber bearings used as passive energy dissipators in bridges, buildings, and power generation plants is defined by the characteristic viscoelastic behavior of elastomers. Therefore, in this study, the viscoelastic behavior of natural rubber-based compounds used in rubber bearings with different content of carbon black is evaluated. Rheometric tests were performed to study the damping properties and curing parameters of the compounds. Transient tests, which are representative of the operating conditions of rubber bearings, were carried out to study the isochronous stress-strain relation evidencing a non-linear behavior under specific deformation states. Compression, shear, and tensile tests exhibited time-dependent mechanical properties. Moreover, energy dissipation in compression and shear increased for the higher carbon black content compound. Compression set exhibited permanent deformation of the compounds tested at accelerated temperature conditions. Experimental results obtained in this work have great importance for designers in order to evaluate the damping and mechanical behavior of natural rubber compounds related to rubber bearings performance.