Researchers at the Leibniz Institute of Polymer Research Dresden (IPF, Dresden / Germany; www.ipfdd.de) have developed a new method for monitoring the structural health of continuous glass-fibre reinforced composites. The method involves inducing electrical conductivity in the glass fibre surfaces and in the composites’ interphases by applying electrically conductive carbon nanotubes (CNT) in a coating system. The composite is then mechanically loaded, causing the CNT network to deform, and this deformation can be measured as a change in electrical resistance.

Irreversible damages to the composite material caused by defects in the interphase or the failure of the reinforcing fibres can then be detected by observing changes in electrical resistance, the researchers explained. The application of CNT-based interfacial sensors in continuous glass-fibre reinforced composites allows defects to be identified at an early stage, they added.