Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
565578 | Mechanical Systems and Signal Processing | 2013 | 14 Pages |
In the case of thin plates, there exist two modes of propagation which travel at different velocities and exhibit dispersion characteristics. Techniques that are based on Gabor wavelet transform or cross-correlation technique are commonly used to locate acoustic emission (AE) events which occur in large plates. Due to side-edge reflections and short source-to-sensor distances, these techniques are not suitable for small plate-like specimens. If the thickness of the plate-like specimen is smaller than a specific value, the first-coming (extensional) mode will show non-dispersive behavior in AE frequency range. Under such a condition, the conventional localization method can be used for detecting first-arrival times on non-dispersive extensional mode. In previous paper, authors of the paper developed a first-arrival automatic determination technique based on Akaike information criterion (AIC) for thin metal plates. This paper compares this technique with another AIC approach, STA/LTA method (short-term average/long-term average) and a standard threshold-crossing technique. The comparative analysis includes blind tests, and is provided on four datasets recorded by a four-channel recording system. The three of four datasets were generated using two types of artificial AE sources (Hsu–Nielson source and laser impulse), while the fourth one contains real-measurement data. Each dataset corresponds to measurement made on a thin-plate specimen of a different material or geometry.
► First-arrival determinations of extensional modes could estimate source locations. ► The choice of characteristic function is a crucial factor for the first-arrival detection. ► Parameters of approaches were optimized by a dataset and tested on other datasets. ► Two-step AIC approach showed the best performance in comparison to other techniques.