Multi-impact source localisation on aircraft composite structure using uniform linear PZT sensors array

Composite structures are often struck by foreign objects at multiple locations. Multiple dents may be found on the composite structures such that it is hard to determine the number of impact events. This research presents a multiple impacts localisation method based on the near-field 2D multiple signal classification (2D-MUSIC) method for the composite structure. When multiple impacts are loaded on the plate, it is difficult to localise the positions of multiple impacts because of the overlapping of elastic waves produced by multi-impacts and the edge reflection of the plate. The MUSIC approach can provide estimation of the parameters of multiple emitters without any signal separation of mixed multi-impacts. It is well known that the performance of the MUSIC algorithm largely depends on the successful determination of the number of impacts. Gerschgorin disc theorem is applied for estimating the number of impacts. To verify the proposed method, experiments were preformed on the composite structure. The estimation of the number of impacts and localisation results are in good agreement with the actual impact occurrence. Finally, the proposed method was applied to a real aircraft composite oil tank which showed its successful performance on complex composite structures.