A Damage Imaging Method Based on MUSIC Algorithm of Linear Sensor Array for Aircraft Structure

Abstract

The performance and behavior characteristics of in-service aircraft structures can be affected by damage from external conditions such as impact, loading abrasion and corrosion, which seriously influences the safety of aircrafts. Hence, damage monitoring and localization has become a topic of significant interest in structural health monitoring (SHM) and widely researched. Since the guided wave is sensitive to small damages and can monitor large area region, guided wave based SHM method is one of the most potential SHM methods for aircrafts. Recently, multiple signal classification (MUSIC) is applied to the guided waved based SHM method for damage localization. In this paper, a damage imaging method, which combines the MUSIC (Multiple signal classification) algorithm and linear sensor array, was proposed and used for monitoring the aircraft structure damage. This method utilized the array signal processing method based on MUSIC algorithm, which performed the eigenvalue decomposition of the covariance matrix of array signal and then calculated the spatial spectrum by direction scanning to realize damage imaging. The method had an advantage of arranging the linear sensor array easily. The experiment on the aircraft structure had been established. Experimental results showed that the proposed method can realize damage imaging on aircraft structures accurately and the damage localization error was less than 2 cm.