About Nonlinear Behavior of Unidirectional Plant Fibre Composite

At room condition and standard strain rate, unidirectional glass fiber reinforced organic polymers show linear behavior under longitudinal loading (the same with carbon fiber). Oppositely, plant-based reinforced organic polymers show often nonlinear behavior. We describe a viscoelastoplastic model based on eight independent parameters dedicated to simulation of plant fiber composite mechanical behavior. This model has been previously validated with flax twisted yarn/epoxy composite at room condition. We analyse now an unidirectional flax/epoxy composite at different strain rates to promote a mechanical behaviour with `three apparent regions' visible in case of longitudinal loading. We show that adding of a strengthening phenomenon is a good solution to improve phenomenological model of plant fibre composite.