Numerical simulation of ultrasonic guided waves in welded joint

In order to inspect the long weld efficiently, the weld-guided ultrasonic waves are studied in this paper. By using the finite element method, the propagations of the compression and the shear weld-guided modes are studied and compared. The energy of the two modes along and across the weld are analyzed using Hilbert envelopes. The results show that the shear weld-guided mode decays less than the compression mode along the weld, and the energy of the shear mode is more concentrated in the weld and heat-affected zone compared to the compression mode, which means the shear mode is more suitable for inspecting the weld. The interaction of the shear mode and the damage in the weld and the heat-affected zone is also studied. The results show that the damage reflected signal in the weld can be used as the characteristics signal for detecting the damage. The damage localization capability of the shear weld-guided mode is then verified by a case study. The works in this paper show that the damage in the long weld and its heat-affected zone can be detected and located using the shear weld-guided mode from one single transducer position.