Abstract
Electrical resistivity has been used to detect the internal damage inglass fibre-polyester composite sheet materials. It is shown that theintroduction of microstructural damage to the composite increases theelectrical resistivity in a direction perpendicular to the plane in which thefibres lie. In these experiments, the samples were subjected to somepredetermined value of impact energy using a drop weight tester. The impactenergy causes fibre-matrix debonding and microcrack propagation within thematrix and fibres. The measurement of the electrical resistivity before andafter impact reveals a linear relation between the electrical resistivity andthe magnitude of the applied impact energy. The reproducibility of the data washigher (within ±2%) for the less damaged samples. For the more severelysamples, however, the reproducibility was poorer (within ±8%). This is a goodfeature, as the extent of damage in the less severely damaged samples cannot bedetected by visual inspection.