Multiphase Flow Coupling Behavior of Bubbles Based on Computational Fluid Dynamics during AFP Process: The Behavior Characteristics of Bubbles during AFP Process

To investigate the mechanism of the effect of process parameters on bubble flow behavior during automated fiber placement (AFP) and the relationship between the bubble and voids, mechanical properties of laminates, this paper analyzes the multiphase flow coupling behavior of the bubble and fiber formation using computational fluid dynamics (CFD) and finite element (FE) method under different AFP process parameters. The effects of AFP process parameters on bubble characteristics and fiber deformation are then discussed, respectively, including bubble displacement, maximum cross-sectional area, the lowest internal temperature of the bubble, bubble breakup, and maximum deformation of the fiber. Furthermore, the AFP and corresponding test experiments are performed to investigate the relationships between different bubble characteristics and void content, mechanical properties, mainly interlaminar shear strength (ILSS) and flexural strength (FS). The results show that the maximum cross-sectional area of bubbles is closely related to the AFP process parameters. The FS and ILSS are positively correlated with the maximum cross-sectional area. With the increase of bubble displacement and fiber maximum deformation, FS and ILSS are first increased and then decreased.