A contribution to the chemomechanics of elastomers surrounded by liquid media: continuum mechanical approach for parameter identification using the example of sorption experiments

摘要

Rubber components are used in almost all areas of industrial applications and are often surrounded by liquid media. Caused by thermodynamical reasons the ambient medium is diffusing into or out of the solid. In consequence, the solid can change in mass, volume and material properties. In this study, the diffusion and swelling behaviour using the example of an application of acrylonitrile-butadiene rubber (NBR) in mesitylene is experimentally investigated. For this purpose, sorption experiments are carried out. Within the framework of continuum mechanical material modelling, a thermodynamically consistent approach is presented, which describes non-linear diffusion of fluids in solids including the swelling phenomenon. Finite strains of the solid as well as an exchange of mass, linear and angular momentum, energy and entropy for open systems are considered. The resulting governing equations of such a multi-field problem are solved using the finite-element method. An optimisation strategy is presented by performing inverse calculations with the numerically converted material model to identify its relevant material parameters. Finally, the swelling of an NBR sealing in mesitylene is simulated.