Strain rate sensitivity of a bio-based composite flax/Elium^® thermoplastic matrix.

Flax fiber reinforced composites (FFCR) are remarkable materials for their lightweight, strength and low environmental impact. In this study, an innovative FFRC with a recyclable matrix suitable for industrial applications is tested. Investigations focused on the strain rate sensitivity of this composite over a wide range of strain rates in compression from 0.004 s^-1 (quasi-static) to 2500 s^-1 (dynamic). The dynamic tests are performed with the Split Hopkinson Pressure Bar technique. The tested composite shows an important strain rate sensitivity with an increase of the Young’s modulus and the maximum compressive stress and a decrease in the strain at break. After reaching the maximum compressive stress, significant delamination occurs in the composite. Experimental results allow us to identify an elastic behavior law and model the composite failure. Additional information on the fracture mechanisms is obtained through microscopic observations. This study contributes to a better understanding of the FFRC dynamic mechanical behavior and provides fundamental experimental data to identify models for integration in calculation codes for engineering applications.