CONDITION MONITORING IN COMPOSITE-MATERIALS - AN INTEGRATED SYSTEMS-APPROACH

This paper presents the results of a collaborative project, the object ive of which was to investigate the potential offered by combining ult rasonic Lamb wave interrogation of composite material structures, inso nifying the whole structure, with a single wavefront integrating optic al fibre detector. The system, which was designed primarily for condit ion monitoring rather than defect imaging, proved to be capable of det ecting small (centimetre square) delaminations, millimetre-sized holes and impact damages of a few joules, all with insonification wavelengt hs of the order of 2 cm. Data extraction proved to be extremely import ant since the damage-detection process relies essentially on analysing scattering signatures rather than attempting to image defects and dam age. The system-dubbed SISCO (Structurally Integrated Systems for comp rehensive evaluation of COmposites)-indicates that self-monitoring str uctures can be efficiently designed using controlled insonification an d a relatively sparse sensor array, presenting a contrast to the more conventional imaging approach involving far more complex sensing array s and detection and signal processing algorithms.