Optimisation of an in-process lineal dielectric sensor for liquid moulding of carbon fibre composites

A dielectric sensor appropriate for process monitoring of carbon fibre composites manufacturing has been optimised and implemented in Resin Transfer Moulding (RTM). The sensor comprises a pair of twisted insulated copper wires and can be adapted to monitor both flow and cure. To simulate the dielectric response of the sensor, an electric field model was developed. The model was coupled with a multi-objective optimisation genetic algorithm to optimise the sensor design. The optimisation showed that increasing wire radius and decreasing coating thickness increases sensor sensitivity. Different sensor designs were implemented and used in a series of RTM trials to validate the technology in industrial conditions. The selelcted sensors operated successfully at pressures up to 7 bar and temperatures up to 180 degrees C. A low diameter sensor using copper wire coated with polyimide showed the best response monitoring flow with an accuracy of 95%, whilst also following the cure and identifying vitrification.

Automated summary

The study optimized a dielectric sensor for process monitoring in RTM, validated the technology's feasibility in industrial conditions through simulation and optimization. Increasing wire radius and decreasing coating thickness were found to improve sensor sensitivity, allowing for effective operation at high pressure and temperature.