Research progress in low-velocity impact monitoring technology for aircraft structures

Low-velocity impacts pose a severe threat to aircraft flight safety by potentially damaging aerospace structures. Impact monitoring, which can locate the source of impacts in real time, reconstruct load histories, and estimate impact energy, is a key technology in structural health assessment, crucial for ensuring aircraft operation safety. This article provides an overview of the general process of the impact monitoring technology. Representative impact localization methods are summarized, including sparse sensor array based time difference methods, time reversal focusing methods, reference database methods and machine learning methods, dense sensor array based beamforming methods, sensor cluster methods, multiple signal classification methods, and spatial wavenumber filtering methods, as well as other non-wave signal based methods. Two categories of impact load reconstruction methods, i.e., model-based methods and machine learning methods, are discussed, along with methods for impact energy identification. Considering the current state of the impact monitoring technology, the article explores the technical challenges it faces and its future development trends.