Thickness Variation Model of Liquid Composite Molding Based on Zero‐Leakage Resin Infusion Process

In liquid composite molding (LCM) processes, controlling the final thickness of the laminate is critical for ensuring dimensional accuracy and performance reliability, yet it remains a significant challenge due to the complex interplay between resin flow and preform compaction. This paper introduces a Zero‐leakage Resin Infusion (ZRI) process designed to enhance control over resin impregnation and part quality. A comprehensive analytical model is developed to predict the dynamic thickness variation of a fabric preform throughout the entire ZRI process. The model systematically addresses three distinct physical stages: (i) the initial flow and mold‐filling stage, where resin pressure gradients cause spatial thickness variations; (ii) a resin impregnation stage, where continued resin influx leads to preform swelling; and (iii) a final continuous impregnation stage, where pressure homogenization and fabric relaxation occur. To validate the model, infusion experiments were conducted on carbon fiber laminates, with preform thickness monitored in situ using a non‐contact 3D optical measurement system. The model's predictions show good agreement with the experimental results for all three stages, confirming the model's accuracy and robustness. This work not only reveals the underlying mechanisms of thickness evolution in the ZRI process but also provides a valuable analytical tool for process optimization and engineering applications requiring precise dimensional control.