Sensor technology for composites

The National Composites Centre (NCC) in the UK has developed new dielectric sensor technology designed to capture data during liquid resin processes.

The research was started at Cranfield University and demonstrated by aerospace engineering company Meggitt.

The NCC conducted trials of the dielectric sensors, which use capacitance to measure the dielectric permittivity of a surrounding medium, at aerospace material processing conditions of 7 Bar and 180°C. According to the center, the sensors could precisely detect resin as it flowed inside the preform, as well as its cure progression. The sensors provided no adverse effects on either the process or part quality.

The team next worked with the Advanced Manufacturing Research Centre (AMRC) in Sheffield and Meggitt to integrate the sensors into a closed resin transfer molding (RTM) tool, with no modifications to the tool being required. In trials, the sensors successfully captured data on the resin flow progression and degree of cure, agreeing with results from previous reports and theoretical models.

“The sensor system is a significant step toward the digitalisation of resin RTM by providing accurate data capture of resin infusion,” the NCC said in a press release. “This can be used to validate computer simulations of the process, enabling industry to reduce the number of initial experimental trials, facilitate a ‘right first time’ approach, crucially reducing the time and cost spent manufacturing components.”

“We were interested in applying this sensor technology as a way of building in a smart function to the RTM process for monitoring part production,’ added Dr Peter Karapapas, principal engineer at Meggitt. “This is with the aim of minimising the time and effort required in post-production NDT [non-destructive testing] and inspection on future components as we move towards digital manufacturing. The sensors were robust and effective during the demonstration on the large-scale composite housing part designed for a civil aviation jet engine air-oil heat exchanger.”