Two-dimensional near-field multiple signal classification algorithm–based impact localization

Abstract

The susceptibility of composite materials to internal damage caused by low-velocity impact is well known and creates a major concern related to structural health monitoring. This research presents a near-field impact monitoring method based on the two-dimensional multiple signal classification method for the composite structure. Since elastic waves attenuate quickly in the complex aircraft composite structures and impacts may happen near the sensors, near-field impact monitoring method is important. However, most of the methods reported are based on the far-field assumption. When impacts occur not far enough from the sensors, this belongs to the near-field situation, where the elastic wave fronts are spherical and the direction estimation method with the plane wave hypothesis is no longer valid. Hence, this article focuses the research of a near-field multiple signal classification–based impact localization method. To verify the proposed method, two experiments are performed on composite structures. The localization results are in good agreement with the actual impact occurring positions in near-field area. Finally, the proposed method is applied to a real aircraft composite oil tank showing its successful performance on complex composite structure.