Evaluating the influence of a multiaxial static preload on the dynamic properties of elastomers
Résumé
A general experimental procedure is proposed to characterize the dynamic properties of elas- tomers under large static multiaxial preloads through tension-torsion tests.The experimental set-up is presented, before paying attention to the post-treatment. Because of the heterogeneity of the strain induced by torsion, calculating stresses is too complex, and it is proposed to use some global equivalent quantities. Storage and loss moduli in both tension and shear are then deduced from these quantities, extending classical definitions of dynamic moduli around an undeformed state to a deformed one. Then, the influence of frequency and amplitude on loss and storage moduli is studied, as well as the influence of the preload. The preload is represented either by measures of the strain, through invariants of the Hencky strain tensor, either by its static moduli in tension
and shear. Finally, the validity of the proposed procedure