Impact source identification in a carbon fiber reinforced polymer plate by using embedded fiber optic acoustic emission sensors

This paper demonstrates the use of four embedded fiber optic acoustic emission sensors (FOAESs) to identify the impact source of the carbon fiber reinforced polymer (CFRP) plate. The optical waveguide method and computer simulation were both applied to explain the principle of FOAES, which proved that any one of the two output terminals of FOAES was able to reveal frequency response characteristics of stress waves. The response characteristics of the FOAES to the stress waves were calibrated and discussed for comparisons of before-and-after embedded in the CFRP plate. Propagation velocities of stress wave depending on the direction in the CFRP plate were measured by FOAESs as the information for impact source identification. A simple and efficient algorithm based on the intersection of hyperbolic curves was presented to estimate the impact source location. An automatic monitoring system with the tailored program of localization algorithm was introduced for online real-time impact source identification. Experiments of impact source localization were achieved by using the FOAESs array mounted on the surface and embedded in the CFRP plate. The measured results agree well with the actual impact sources in the CFRP plate embedded with FOAESs. Furthermore, the research of composites structures embedded with FOAESs is conductive to developing the intelligent integration of structural health monitoring (SHM).