Linear Location of Acoustic Emission Sources with a Single Channel Distributed Sensor

In this paper, distributed sensors are evaluated for structural health monitoring. A distributed sensor is formed by electrically connecting a number of acoustic emission sensor nodes in series. The individual nodes are placed at strategic locations on the structure. This arrangement allows the detection of acoustic emissions occurring at multiple regions of the structure using a single monitoring channel, and hence significantly reduces the cost, complexity, and weight of on-board instrumentation. The performance of the distributed sensor is compared against that of conventional single node sensors on a fiberglass bar and on a graphite epoxy sandwich panel using simulated acoustic emission signals. These comparisons indicate that a single distributed sensor can monitor large areas of the structure without degrading the signal amplitude or the frequency bandwidth. A new analysis procedure to determine the location of the acoustic emission source from this single channel data is also introduced. Experiments performed on a steel bar indicate that reasonable accuracy can be achieved in locating the acoustic emission sources along a line segment just using the single channel data from the distributed sensor.