Designed multifunctional sensor to monitor resin permeation and thickness variation in liquid composite molding process

Abstract

Process monitoring of resin permeation in fiber preform and fabric thickness variation in liquid composite molding (LCM) is important to ensure the quality of the composite parts. However, existing technologies cannot monitor both of them by a single sensor and may disrupt resin flow patterns or fiber deformation inside the part due to their large thickness or rigidity. To achieve accurate monitoring of the signals within the part during the LCM process, a thin and flexible Pt-coated film capacitive sensor was designed to minimize the effect of sensor on flow behaviour. The accuracy of the embedded sensor was verified by the consistent resin flow front and the negligible fiber deformation around the sensor. Moreover, the flow front, thickness variation and curing inside composites preform in LCM can be captured based on the variation of the capacitance curve and its second derivative. These results demonstrated that this multifunctional sensor offers a new solution to obtain signals accurately in the part in LCM.