Damage Index Weighted Delay-and-sum Imaging Method Based on Time Reversed Ultrasonic Lamb Wave for Damage Localization

摘要

Ultrasonic Lamb wave is an important measure for nondestructive testing and imaging of defects or damages within plate structure material. In this field, the damage index probability and delay-and-sum are two commonly used imaging methods. The first one can identify multiple defects with low localization accuracy, however, the second one has high localization accuracy only in the case of single defect. By combining the advantages of the two methods, this paper proposed a novel damage index weighted delay-and-sum (DIWDAS) imaging method based on time reversal Lamb wave to solve the problem of accurate localization of multiple defects in plat structure with sparse ultrasonic sensors. Experiments on samples of tested metal plates with one and two defects manifested the effectiveness of the proposed method.