INFLUENCE OF THE ANISOTROPIC CHARACTERISTIC ON THE ACCURACY OF ACOUSTIC EMISSION SOURCE LOCALIZATION WITH L SHAPED SENSOR CLUSTER

Composite materials are increasingly being used in the structure of aircraft. However, this type of materials is commonly encountering damage companied with acoustic emission (AE) events. In order to ensure the safety of structures during service, it is urgent to develop structural health monitoring methods able to localize AE source in composite components as they occur. Kundu et al [1] for the first time proposed a technique using L-shaped clusters to localize AE source in anisotropic plates without knowing the pre-defined velocity. However, the direction dependent group velocity may lead to a large error if the group velocities in some anisotropic materials vary widely. In this paper, whether the characteristic of anisotropy has a great influence on the localization results and the principle of how this characteristic affects the AE source localization results are investigated. The results show that localization results of isotropic plate are obviously better than that of anisotropic plate due to the direction dependent velocities of anisotropic plate, which proves that the characteristic of anisotropy will affect AE source localization results. It is also found that the variation of localization orientation error is consistent with the local velocity gradient.