In-line Eddy-Current Testing (ECT) of Carbon Fibre Reinforced Polymers (CFRP)

Carbon fibre reinforced polymers (CFRP) materials have become a workhorse of the aerospace industry. Automated fibre placement (AFP) systems have increased the rate at which composite materials can be manufactured, but there is a severe lack in quantitative quality monitoring techniques that can ensure manufacturing tolerances are met. One potential solution is to employ high-frequency eddy-current testing (ECT), which is non-contact and a high-speed measurement, making it suitable for in-line monitoring. 

The ideal time to inspect AFP parts is during manufacture so as to detect faults early when they can be corrected easily. However, the properties of uncured composite components behave very differently to cured composites and the inspection environments can also introduce unwanted sources of error. 

This research aims to develop an in-line and high-speed eddy-current inspection technique for characterisation of CFRP materials. 

Aims and Objectives  

Determine how layup structure alters the effective conductivity of the structure. 

Characterise differences in ECT response to cured and uncured carbon fibre composite materials.  

Develop advanced measurement & data-analysis techniques for evaluating structural properties such as fibre orientation, stacking sequence and fibre density variations. 

Specific requirements for the probe design: 

  1. have a high sensitivity to detect small defects with a very good signal-to-noise ratio when handled with conventional ECT equipment;  
  1. be capable of detecting distinct kinds of defects (morphology and locations);  
  1. be easily customizable and affordable.