Weld defect detection method using ultrasonic Lamb wave

Chi, DaZhao; Harbin Institute of Technology; China

Chi, D.; Harbin Institute of Technology; China
Gang, T.; Harbin Institute of Technology; China
Qi, C.; Harbin Institute of Technology; China

ID: ECNDT-0337-2018
Session: Guided Waves - Structural Health Monitoring
Room: G3
Date: 2018-06-15
Time: 11:30 - 11:50

Ultrasonic Lamb waves are interesting for long distance testing since it offers the potential for rapid screening from a single transducer position. Experimental observation on a large welded plate has revealed that there existed ‘weld-guided’ modes that can propagate along the weld and concentrate the energy in and around the weld. In this paper, in order to understand the nature and propagation characteristics of ultrasonic Lamb wave in weld, both experiment and simulation works are carried out. Artificial defects including surface open slots and flat bottom holes are made in a weld seam with idealized geometry. An adjustable angle wedge with saddle-shaped is designed to meet the geometry of the weld. In order to further understand how the Lamb wave is affected by the geometry and frequency, a finite-element (FE) simulation on an idealized welded plate geometry is performed. The theoretical analysis and numerical simulation results are in good accordance with the experiments.