Real-time monitoring of vacuum-assisted resin infusion using electrical resistance and corresponding bernoulli analyses for resin impregnation

초록

Carbon fiber-reinforced plastics (CFRPs) have attracted significant attention in aerospace and automotive applications owing to their high specific strength and lightweight characteristics. However, compared with conventional materials, CFRP manufacturing requires longer processing times and higher production costs, highlighting the need for reliable real-time monitoring systems. Although various monitoring approaches have been developed for vacuum-assisted resin infusion (VARI), accurately identifying resin flow and evaluating impregnation quality in large and curved composite structures remain challenging. In this study, a real-time monitoring system for VARI manufacturing was proposed based on electrical resistance changes of carbon fibers using cost-effective copper-wire electrodes. The proposed system enables detection of resin arrival at multiple locations and evaluation of impregnation behavior without additional embedded sensing devices. Furthermore, Darcy’s law and Bernoulli’s equation were integrated to quantitatively analyze resin flow characteristics considering different specimen tilt angles and resin reservoir locations. The proposed monitoring method successfully identified the resin arrival time at multiple electrode locations within 4 s. In addition, the experimentally measured resin flow velocity showed good agreement with the numerical predictions, with discrepancies of only 8.43% and 9.42% under the horizontal (0°) condition. The proposed real-time monitoring system provides not only in-process evaluation of resin impregnation status but also quantitative guidance for optimizing resin reservoir conditions, demonstrating its potential for improving the reliability and quality of VARI-manufactured CFRP structures. © 2026 Published by Elsevier B.V.

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