By harnessing the potential of guided ultrasonic waves for inspecting long distances, this method offers the opportunity to enhance the speed and precision of structural inspections. This study delves into the outcomes of employing the normal modes expansion method and explores the impact of the guided ultrasonic wave generation source. The investigation revealed that the L (0, 2) mode proved to be suitable for inspection due to its consistent speed across a broad range of frequencies. Afterward, a wave excitation source with defined geometric characteristics was introduced into the analysis. Its influence on the resulting wave field was examined by integrating the semianalytical finite element (SAFE)‐based solutions into the governing expressions through a normal‐mode expansion procedure. Ultimately, the study determined the modes generated in the pipe, along with obtaining the amplitude coefficients of these modes. It was observed that utilizing an axial symmetric wave generation source with a peripheral angle of 360° and a length of 20 mm prevents the generation of asymmetric modes ( L ( n , 2)) in the pipe wall. In this configuration, only the symmetric mode L (0, 2).
Gazarzadeh et al. (2026) studied this question.