Constitutive model to predict the viscoplastic behaviour of natural fibres based composites

The mechanical behaviour of traditional composites is usually assumed as linear-elastic up to failure. However, composites based on natural fibres are characterized by non-linear elasticity, viscous effects and plastic strains before failure. This study presents a rheological model to predict the viscoplastic behaviour of natural fibres based composites. The model was calibrated using a stress-strain curve and two relaxation tests for three different composites reinforced with flax, jute and cotton fibres. The model predicted successfully the behaviour of biocomposites loaded at different strain rates. (C) 2016 Elsevier Ltd. All rights reserved.