An improved MUSIC damage diagnose algorithm with transmitter beamforming for composite structures

Guided waves attenuate seriously on some structures, such as carbon fiber composite structures. Specially, the low signal to noise radio (SNR) of guided waves, resulting from high attenuation, limits the accuracy of guided waves based methods. Among them, sensor array based imaging methods have been gradually studied to synthetic guided waves from different excitation-sensing paths, which could improve the SNR of guided waves to some degree. However, these methods usually synthetic guided waves on only the excitation or sensing side, which are still not enough for high attenuation structures. To solve this problem, an improved MUSIC damage localization method with transmitter beamforming is proposed in this paper. Transmitter beamforming is carried out to make the excitation guided waves focused on special positions and MUSIC algorithm is used to synthetic the received guided waves, scattered from damage, to further improve the damage imaging accuracy. At last, an experiment on the carbon fiber composite plate is carried out to verify this proposed method. Experimental results show that the proposed method can realize accurate damage imaging with the angle errors less than 2° and the distance errors less than 30mm.