Full-field monitoring of resin flow using an area-sensor array in a VaRTM process

Conventional resin flow monitoring relies on point measurements even if using grid sensing, and it is difficult to estimate an accurate flow front or defect figuration. The current work investigates full-field monitoring of resin flow during a vacuum-assisted resin transfer molding (VaRTM) process using an area-sensor array. The squared area sensors are aligned as a matrix on a thin polyimide film without any un-sensing space; thus the film measures the full-field flow monitoring, and does not miss a dry spot that may occur anywhere on the film. To identify the precise flow front and dry spots, the impregnated area is estimated by minimizing the residual sum of squares between the measured and estimated impregnated area ratios. To demonstrate the applicability of the proposed method, the area-sensor array is applied to monitoring a VaRTM resin flow on glass fiber reinforced plastic (GFRP) and foam-cored structures. As a result, the precise figurations of the flow front and the dry spot were successfully estimated in real time.