title: Minimum variance imaging based on correlation analysis of Lamb wave signals.
abstract: In Lamb wave imaging, MVDR (minimum variance distortionless response) is a promising approach for the detection and monitoring of large areas with sparse transducer network. Previous studies in MVDR use signal amplitude as the input damage feature, and the imaging performance is closely related to the evaluation accuracy of the scattering characteristic. However, scattering characteristic is highly dependent on damage parameters (e.g. type, orientation and size), which are unknown beforehand. The evaluation error can degrade imaging performance severely. In this study, a more reliable damage feature, LSCC (local signal correlation coefficient), is established to replace signal amplitude. In comparison with signal amplitude, one attractive feature of LSCC is its independence of damage parameters. Therefore, LSCC model in the transducer network could be accurately evaluated, the imaging performance is improved subsequently. Both theoretical analysis and experimental investigation are given to validate the effectiveness of the LSCC-based MVDR algorithm in improving imaging performance.
authors.affiliation: State Key Laboratory of Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an, Shannxi Province 710049, PR China.
authors.forename: Jiadong
authors.initials: J
authors.lastname: Hua
authors.affiliation: State Key Laboratory of Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an, Shannxi Province 710049, PR China; Shaanxi Key Laboratory of Mechanical Product Quality Assurance and Diagnostics, Xi'an Jiaotong University, Xi'an, Shannxi Province 710049, PR China. Electronic address: jinglin@mail.xjtu.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an, Shannxi Province 710049, PR China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an, Shannxi Province 710049, PR China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Luo
keywords: Damage detection; Lamb wave; Local signal correlation coefficient; Minimum variance distortionless response