Comparative Study on the Mechanical Behavior of Flax and Glass Fiber Multiaxial Fabric-Reinforced Epoxy Composites

TL;DR

This study compares the mechanical performance of composites made with flax and glass fibers, finding that flax composites are viable for lightweight applications.

Contribution

A novel yarn-free flax NCF was developed to improve fiber alignment and composite performance.

Findings

Glass fiber composites have higher absolute strength and stiffness.

Flax NCF composites offer competitive specific properties due to improved fiber alignment.

Flax NCFs are mechanically feasible for semi-structural lightweight applications.

Abstract

This study presents a comparative investigation of the mechanical performance of epoxy-based composites reinforced with ±45° multiaxial non-crimp fabrics (NCFs) made from natural flax fibers and conventional glass fibers. Flax fibers, despite their attractive sustainability profile and favorable specific mechanical properties, are typically processed into twisted yarns for textile reinforcement, which compromises fiber alignment and reduces composite performance. A novel yarn-free flax NCF was developed using false twist stabilization of aligned slivers to eliminate the negative effects of yarn twist. Composite laminates were manufactured via vacuum-assisted resin infusion (VARI) under identical processing conditions for both flax- and glass-based reinforcements and tested for tensile, compressive, and flexural behavior. The results show that, although glass fiber composites exhibit superior absolute strength and stiffness, flax-based NCF composites offer competitive specific properties and benefit significantly from improved fiber alignment compared to yarn-based variants. This work provides a systematic comparison under standardized conditions and confirms the mechanical feasibility of flax NCFs for semi-structural lightweight applications.

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