Constraints on monitoring resin flow in the resin transfer molding (RTM) process by using thermocouple sensors

Composite materials – modelling, prediction and optimization

“…Although the existing simulation codes, developed thanks to the efforts of several research groups, have led to better understanding and more effective planning of LCM processes, a further open question is the development of online monitoring and control systems able to optimally handle unpredicted variations in the processing conditions. Different approaches to fl ow monitoring, based on image analysis, electrical signal processing, thermocouples, fi bre optics, ultrasonic methods and dielectric measurements, have been proposed, compared and discussed in the literature [99][100][101][102][103][104][105][106][107], showing advantages but also limitations related to invasiveness, excessive noise, delay or tooling cost, depending on the specifi c choice. An automatic control system should have decision skills, based on a proper consideration of the different possible fl ow scenarios, in order to be effectively applied.…”

Monitoring of resin flow in the resin transfer molding (RTM) process using point-voltage sensors

“…Thus, thermocouples can also be used for cure monitoring. The limitations on the thermocouple usage are discussed in [13].…”

“…To monitor resin flow and/or cure in LCM processes, the most frequently used sensors are SMARTweave [2][3][4], dielectric [5][6][7][8], ultrasonic [9,10], fiberoptic [11,12], thermocouple [13], pressure transducer [5,14,15], and point-and lineal-voltage sensors [16,17].…”

Processing

“…Such methods include SMARTweave sensor grids [44], dielectric sensors [1,45À47], ultrasonic sensors [48,49], sensors based on fiberoptic [50À54] and Fiber Bragg Grating (FBG) systems [47,55,56], thermocouples [1,57], pressure transducers, digital camera-and photo-based systems, time-domain reflectometry (TDR) [3,58], and point-and linealvoltage sensors [59]. One basic distinction between the sensor systems can be made between sensors that collect information on the cure state or the resin position at specific locations of the mold (point-wise detection, majority of the available sensors) and sensors that cover a larger area of the mold as in, for instance, digital camera systems.…”