Total focusing imaging simulation and algorithm optimization of debonding defect of composite bonding structure
                   FAN Xueteng1, FU Xibin2, HUANG Xuebin2, ZHONG Shuncong1,3,FANG Bo1, LIN Qiben1, TANG Changming1

(1.School of Mechanical Engineering and Automation,Fuzhou University,Fuzhou 350108,China;2.Xiamen Special Equipment Inspection Institute, Xiamen 361000, China;3.School of Mechatronics Engineering and Automation, Shanghai University, Shanghai 200072, China)

Abstract: Aiming at the problem that it is difficulty to detect the debonding defects of composite bonded structures with large differences in material acoustic parameters, the detection principle and difficulties of such structures were studied, the influence of the size of the debonding on the amplitude of echo was analyzed.The finite element detection model of conventional PA imaging detection and total focusing method imaging detection for composite bonding structure was established respectively, a partialsequence local total focusing acceleration method based on directivity theory was proposed.The effective array element sequence was selected by setting the angle threshold to improve the imaging efficiency.The simulation results indicate that the total focusing imaging method has superiority over the conventional PA imaging detection for the detection of such composite bonding structures.After the algorithm is improved, for the 32element phased array probe, the calculation time of imaging detection of the rectangular area between ［-4mm, 4mm］ and ［4mm, 8mm］ by the acceleration method is reduced by 34.7%,without reducing the imaging quality.

Key words: composite bonding structure; debonding defects; total focusing method(TFM) imaging detection; PA imaging detection; acceleration algorithm