A constitutive model for rubber bearings submitted to combined compression and cyclic shear loadings: impact of thermal aging
Résumé
Laminated rubber bearings are commonly used for the seismic isolation of civil engineering structures. During an earthquake, the rubber material is supposed to undergo static compressive loading combined with cyclic shear loading. During long term service, the mechanical properties of this material, mainly shear and bulk moduli, can evolve due to environmental conditions such as temperature, humidity, oxygen. . . This evolution can be related to the reorganization of the rubber network due to the chemo-mechanical interaction [1]. In order to highlight this network evolution, an important experimental investigation will be replicated on rubber samples submitted to oxidative thermal ageing.
When it comes to modelling, rubber is generally assumed to be quasi-incompressible. Nevertheless, in the laminated geometry of bearings, exhibiting a high shape factor [2], modelling the relationship between the hydrostatic pressure versus the volume change is of prime importance. In this contribution, an attempt is made to investigate a relevant constitutive model, using a multiphysics coupling approach, such as the one developed in [3], that allows the combined shear and dilational responses to be handled. To this end, an original experimental set-up is used to obtain a reliable database, useful for the finite element modelling. The experimental results will be used to enhance the proposed model by offering a closer look at the ageing effects on the rubber mechanical properties. This may help to improve the residual life-time prediction for related applications.
[1] L. Steinke, J. Spreckels, M. Flamm, and M. Celina. Model for heterogeneous aging of rubber products. Plastics, Rubber and Composites, 40(4):175–179, 2011.
[2] A. Dorfmann, K.N.G. Fuller, and R.W. Ogden. Shear, compressive and dilatational response of rubberlike solids subject to cavitation damage. International Journal of Solids and Structures, 39:1845–1861, 2002.
[3] S. Lejeunes, D. Eyheramendy, A. Boukamel, A. Delattre, S. Méo, and K. D. Ahose. A constitutive multiphysics modeling for nearly incompressible dissipative materials: application to thermo–chemo-mechanical aging of rubbers. Mechanics of Time-Dependent Materials, 22:51–66, 2018.