Research on single frequency component based MUSIC algorithm for impact localization

Composite materials have been widely used in many aircraft structures due to their high specific strength, light weight, resistance to fatigue and flexibility in design. The susceptibility of composite materials to incur impact damage is well known and creates a major concern related to structural integrity. Since the MUSIC algorithm could successfully detect the source signal under low signal-to-noise ratio without transfer functions and material properties, it has been applied to the structural health monitoring area gradually. However, the impact induced Lamb waves exhibit a wide band performance, which gives rise to the difficulty of obtaining the phase velocity directly. This paper first analyzes the influence of the phase velocity precision to the accuracy of the MUSIC based impact localization method. In order to deal with the phase velocity obtaining problem, the Shannon wavelet is used to extract single frequency components from the impact induced Lamb waves. Based on the obtained phase velocity, the precision of MUSIC algorithm for impact localization is improved. This method is verified on the stiffened structure of an UAV wing box. Experimental results show that the method could realize impact localization on stiffened aircraft structures and has a relatively small error.