Inducing Fiber Entanglement to Achieve Realistic Tow Fiber Volume Fractions in Textile Reinforced Composite Models

Abstract

Meso-scale modeling can be an effective way to predict textile-reinforced composite performance when the geometry of the textile is known. Digital element fiber models can be used to obtain the geometry of the textile reinforcement, but these are frequently too compact because the fibers are parallel within a tow and do not provide as much resistance to compaction as tows with fiber entanglement found in textiles. A novel entanglement simulation procedure was created to obtain more realistic textile geometry. By combining artificial fiber entanglement with manufacturing process simulation, a method was developed to create fiber bundle models using entanglement to control the compaction behavior. To introduce fiber entanglement into a tow, select fibers are swapped with each other in the tow at a cross-section. This allows entanglement to be introduced after the basic textile structure is already made, and prevents individual fibers from leaving the tow and getting entangled into neighboring tows. This fiber entanglement process was controlled by three parameters, which dictate how many, how often, and how far away from each other fibers are swapped. A parametric study was conducted which showed that the entanglement within a fiber bundle could be used to control the compaction pressure versus fiber volume fraction response of the bundle. The method was then applied to a woven textile model where it was found that increasing the amount of entanglement within the tows increased the pressure required to compact the textile to the desired thickness. This method for artificial fiber entanglement and manufacturing process simulation shows the potential to be able to predict the entanglement required to create fiber bundles using a desired mold compression pressure to achieve a desired compaction behavior.