Development of woven and quasi-unidirectional reinforcement fabrics with hemp fibers: study of mechanical and preforming behaviors

The use of hemp fibers for the manufacturing of reinforcements for composite materials is not well common, despite a growing interest of natural fibers in this field of application. In addition to the choice of the type of fiber used, the choice of the type of reinforcement plays an important role in the final properties of the composite material. Unidirectional or woven fabrics are widely used as reinforcement to achieve advanced properties at the scale of composite, depending on the specifications of the final material. In this study, a quasi-unidirectional fabric and two woven fabrics (one balanced and one unbalanced in terms of fiber content) are studied to compare their properties at different levels: mechanical and preforming properties of the reinforcements in dry state and mechanical properties of composite materials reinforced by these fabrics. The objective is to highlight the advantages and drawbacks of both types of reinforcements (woven fabrics and quasi-unidirectional fabrics) in order to be able to select the most suitable reinforcement according to the specifications of the final composite part. As a result, the quasi-unidirectional reinforcement showed enhanced properties both at fabric and composite scale. These structures based on hemp fibers present promising properties that concur structures made of flax and already available on the market.