Vibration‐Assisted Out‐of‐Autoclave Curing of Fiber‐Reinforced Composites: Vibration Propagation Modeling and Its Implications for Resin Flow and Void Suppression

ABSTRACT Mechanical vibration‐assisted molding, as an out‐of‐autoclave curing process, enables high‐quality manufacturing of resin‐based composite components under low‐pressure conditions. However, current research on this process mainly focuses on experimental phenomena of the effect of vibration energy fields, with few studies addressing the mechanisms, often neglecting resin viscosity changes and the influence of fiber structures on vibration propagation, thus limiting guidance for process parameter selection. In this study, a vibration propagation model considering the solid–liquid two‐phase characteristics of composites was developed. The propagation patterns and influencing factors of vibration during the curing process were analyzed, and curing experiments with vibration‐assisted composite preforms were conducted to explore the impact of mechanical vibration on resin flow and void formation. Simulation results show greater attenuation of high‐frequency vibrations in composite preforms, with a larger vibration influence area along the thickness direction than in‐plane. Vibration attenuation decreases with lower resin viscosity but remains significant within the viscosity range during curing. Curing experiment results confirm that vibration‐assisted preforms exhibit more thorough resin flow than vacuum‐pressure‐only areas, with layer thickness increasing along the vibration direction, validating simulation results. Furthermore, compared to vibration applied only within the low‐viscosity range, full‐process vibration leads to a better resin flow and a substantial reduction in void ratio, from 4.31% to 0.58%, optimizing the curing process for composite components with high quality and low void ratio.