GDR CNRS 2024
Multiscale Mechanics of fibrous media

In this paper, the study was focused on the viscoelastic behaviour of Raffia vinifera fibres in the optimization of bio-composites. We designed and constructed a device that was used to carry out the uniaxial tensile creep-recovery test which was validated by the comparative tests carried out on the tensile machine MTS 20/M. Among several models tested, the 8-elements Burger model described better the experimental points and the obtained parameters vary according to the stress. In addition, the creep-recovery behaviour was studied through the Schapery model and its parameters were evaluated. Generally, it appears that these parameters can be modelled by a 3-order polynomial. Then the multiple step loading behaviour was carried out and allowed the 8-elements Burger model to be consolidated with the duration of a load being taken into account to describe it. Finally, from the study of cyclic loading, it showed that the energy dissipated during the first cycle is very important compared to that of the other cycles and it becomes negligible from the 10th cycle. This shows that the Raffia vinifera fibre loses less energy during cyclic stresses.