ABSTRACT
Acoustic Emission Tomography (AET) is a technique in which the elastic wave velocity distribution and source information of AE events by using only the arrival times of the AE events. Firstly, AET identifies source locations and emission times of AE events, then elastic wave velocity distribution is identified on the basis of the identified source locations and emission times. In this algorithm, the identification of the source locations and emission times are conducted separately from the identification of the elastic wave velocity distribution. On the other hand, although the source locations and the emission times are influenced by the change of the elastic wave velocity distribution, the change of the source locations and the emission times are not considered in the identification of the elastic wave velocity distribution due to the characteristic of the conventional AET algorithm. This sometimes causes errors in the resultant elastic wave velocity distribution and a new method to improve the resultant distribution has been demanded. For overcoming this problem, a new algorithm is proposed in this study. The new algorithm considers the changes of the emission times in the identification of the elastic wave velocity distribution. It should be noted that the changes of the source locations are not considered here since the source location changes nonlinearly with the change of the elastic wave velocity distribution and there are difficulties to take it into account. The proposed algorithm is verified by performing a series of numerical investigations under some computational conditions. According to the results of the investigations, it is confirmed that the proposed algorithm improves the resultant elastic wave velocity distribution.
