An Acoustic emission event determination method for acoustic emission testing of tank bottom based on cluster analysis

摘要

Acoustic emission (AE) testing method has been widely used for examining tank bottoms. As there is no need to empty the tanks, this method can save a lot of time and money. The evaluation of tank bottom corrosion based on AE testing method is realized by analyzing the number of effective AE events. An effective AE event is an AE event located on the tank bottom. Each AE event is composed of more than three AE signals received by different AE sensors, and the signals should be generated by the same AE source. However, the traditional AE event determination process is carried out without considering the situation where multiple AE sources generate signals simultaneously. So the traditional AE event determination method may identify the AE signals coming from different AE sources as one AE event, which would produce incorrect test result. Also the traditional AE event determination method would be affected by fake hits due to noise. In order to improve the measurement accuracy, a new AE event determination method based on the cluster analysis is proposed. Experiments showed that the AE events extracted by using cluster analysis method are more accurate. In addition, the cluster analysis method exhibits good noise resistance so that it can increase the accuracy of tank bottom integrity evaluation.