Crack detection in aluminium 2024-T3 plates and in an Airbus A320 slat-track using electrical crack gauges

Structural health monitoring (SHM) is a valuable tool for the investigation and detection of cracks in various engineering structures. Due to the rapid growth of the aviation industry, SHM might have an important place in the field of aeronautics. Appropriate SHM sensors on critical structural components could help to reduce costs by avoiding unnecessary scheduled inspections and will increase the safety of the monitored structures. In this paper, tests on crack gauges made from conductive material are reported. The gauges were mounted on aluminium 2024-T3 plates and on an Airbus A320 slat-track. The aluminium plates along with the A320 slat-track are consecutively painted with layers of primer and coating according to the manufacturer standards. The basic concept of crack detection by the gauges is the interruption of the electrical conductivity by fatigue cracks. The gauges are embedded between the layers of primer and coating in order to be protected and insulated. Results obtained from resistance measurements showed that these crack gauges could detect cracks at a relatively early stage.