An improved adjacent multi-damage “delay-and-sum” imaging method
CAI Jian1; SHI Li-hua2; YUAN Shen-fang1
1. The Aeronautical Key Laboratory for Smart Materials and Structures, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China2. Laboratory of Electromagnetics, Nanjing Engineering Institute, Nanjing, 210007, China
Abstract：Adjacent multi-damage imaging is a difficulty in the research of Lamb wave imaging. Based on the traditional “delay-and-sum” method, an improved adjacent multi-damage imaging method is proposed. To avoid or reduce the overlapping between neighboring damage scattered signals, double side excitation is adopted in the method to generate single mode Lamb wave monitoring signals with higher spatial resolution. Meanwhile, according to the energy attenuation in the propagation of Lamb waves, a compensation factor is introduced to reduce the monitoring distinctions of monitoring signals for different locations. Both theoretical analysis and experiment show that the above two improvements can enhance the imaging results of adjacent multi-damage.
2011, Vol. 30 
