Modelling the effects of various contents of fillers on the relaxation rate of elastomers

This paper describes numerical investigations conducted on filled rubbers. Some experimental data on stress relaxation tests carried out on various filled elastomers evidenced that increasing the content of rigid particles such as fillers or changes in the crystallization index, result in higher values of the stress relaxation rate. This result seems to indicate that higher rigid particle contents promote macroscopic viscoelastic strain. To better understand this effect, finite element analyses were carried out on axi-symmetric unit cells as well as unit cell for numerical homogenization with periodic computations.

► Data from stress relaxation tests on various filled rubbers: rigid particle + matrix.
► Increasing stress relaxation rate with the fillers or crystallites content increase.
► Unit and periodic cells for finite element simulation of complex microstructure.
► Evidence of non-linear strain amplification of the matrix between two fillers.
► Increase in stress relaxation rate due to this strain amplification.