Experimental investigation of piezoelectric wafers in monitoring the resin transfer moulding process

The objective of monitoring the composite manufacturing process resin transfer moulding (RTM) is pursued by means of applying piezoelectric wafers. First, the sensitivity of the piezoelectric wafers to their area wetted by a viscous liquid was evaluated to shed light on the possibility of utilizing the wafers for the inspection of the resin flow front during RTM. Further, the wafers were immersed in various liquids of different viscosity, to confirm their ability to distinguish such difference. The ability would then be employed to monitor the curing process before gelling of resins. Thirdly, the experimental set-up proved the validity of the wafers for sensing the change of temperature associated with the curing process around the gel point. The overall capability of the piezoelectric wafers to monitor the injection and curing process of thermosets in RTM was investigated, incorporating the wafers in random glass fibre mats of a preform injected with a thermoset resin. Experimental verification has shown promising results and demonstrated potential for using piezoelectric wafers as a novel method for complete process monitoring of composite manufacturing.