EFFECT OF UNIT CELL CONFIGURATION ON BENDING BEHAVIOR OF SPREAD-TOW WOVEN FLAX/PP COMPOSITES IN THE MOLTEN STATE

The use of thermoforming processes to produce thermoplastic composite parts with complex shapes has gained attention due to their ability to integrate favorable mechanical properties, efficient production rates, and economic viability. Among thermoplastic composites, those reinforced with natural fibers like flax stand out for their recyclability and environmental advantages, making them remarkably appealing to industries like automotive.
Spread-tow woven composites, made by weaving thin, flat unidirectional tapes, offer improved fiber alignment, higher fiber content, and better performance per unit weight compared to conventional woven reinforcements [1]. This structure reduces fiber crimp and resin content, resulting in a lighter composite with enhanced mechanical properties. These characteristics make spread-tow woven composites attractive for various industries.
During thermoforming, composites experience various deformation mechanisms. Out-of-plane bending is one of the deformation mechanisms during thermoforming, and its interaction with other mechanisms, such as in-plane shear, can contribute to the formation of wrinkles which can affect the structural integrity of the final product. Understanding this mechanism is essential for accurately predicting and optimizing the forming process. This paper investigates the experimental bending behavior of spread-tow woven flax/polypropylene composites under thermoforming conditions, with a particular focus on the impact of unit-cell configuration on their performance.