Evaluation of experience from long-term ae monitoring


A working group within the Committee on Acoustic Emission Testing of the German Society for Nondestructive Testing (FA-SEP of DGZfP) has collected published data on the long-term behavior of the AE or the Guided Ultrasonic Wave (GUW) measurement chain (sensor, sensor coupling and mounting, signal transmission, data acquisition and storage). Since only scant data is publicly available, the working group drafted a questionnaire for collecting respective information from the committee members. The returned questionnaires indicate that data acquisition and storage likely pose problems more frequently than other parts of the measurement chain. The only exception noted was for one case of integrity monitoring at elevated temperatures. In this case, sensor sensitivity was observed to decrease compared to the performance at room temperature, requiring the mounting of additional sensors for achieving AE source location with the same resolution. Based on the empirical information, recommendations for long-term monitoring with AE and GUW are discussed. These comprise, e.g., periodic checks of sensors and measurement chain, periodic data back-up, and planning of maintenance and repair.
