Detection of Inhomogeneities and Cracks in Composite Materials by the Method of Partial Discharges

Composite materials such as concrete or polymer fiber composites contain a large number of inhomogeneities. It is possible to use the method of partial discharges to detect existing inhomogeneities. Tested materials covered with metal electrodes on both sides represent a parallel plate capacitor. Partial discharges have an impact on conductivity at a high electric field and they are important sources of current noise and acoustic emission signals. The concrete samples were measured before and after mechanical loading by the method of partial discharges and the correlation between them was studied. This method may be used for the diagnosis of inhomogeneities and cracks in composite materials.