Analysis and optimization of the deformability of flax fiber nonwoven tapes during the tape-laying process

Abstract The use of natural fibers as recyclable and environmentally friendly materials in technologically advanced products such as composites is widely increasing. Automated tape-laying (ATL) technology is one of the more widely used manufacturing techniques for composites, as it allows process interruptions and facilitates changes of direction. It is especially useful for producing components with complex contours. However, the density and width of the tape-laying preforms, along with the laying angle, can influence the process, potentially leading to defects such as wrinkles. This paper investigates a new approach to mitigating these defects by analyzing the deformation patterns of nonwoven fiber strips during tape-laying through an in-plane bending model. Optical measurements in plane tape-laying tests evaluate the effects of laying path direction, tape width, and elastic modulus on bending resistance. Results show that at a room temperature of 25 °C and a uniform laying rate, fabric tapes exhibit no more than 10% tensile or compressive strain during initial stretching. The high deformation potential of nonwoven is further demonstrated, as large curvature paths can be laid without visible defects when the correct dimensional parameters and reinforcement orientation are chosen. Additionally, a mechanical model based on bias theory is proposed to provide geometric optimization solutions for ATL performs.