BIOFIVAR

There is growing interest in the use of short plant fibers for reinforcing thermoplastics, including for forming parts that can be subjected to high mechanical stress, thanks in particular to the high stiffness/density ratio of these fibers and their biosourced origin. Nonetheless, plant fibers are highly variable in terms of their constituent properties (e.g. cellulose content, number of elementary fibers per bundle, etc.), geometry (length, cross-section, etc.) and mechanical properties (stiffness, strength, adhesion between elementary fibers, etc.). This variability makes it very difficult to model and predict the mechanical behaviour of plant-based short-fibre composites, which is a major obstacle to extending their range of use.

It should be noted that the model currently being developed at LAMIH already allows easy consideration of the specific properties of thermoplastic matrices (viscoelasticity, viscoplasticity, compressible plastic flow, etc...) as well as the complex orientation distributions of short fibers. It is now necessary to introduce the specific features of plant fibers into this model. Multiscale observations will make it possible, on the one hand, to quantify the variability of fiber properties and, on the other, to study particular degradation mechanisms such as intra-bundle decohesion, for example.