Excitation method of guided wave modes in turnout rails with variable cross-section by applied surface tractions

Ultrasonic-guided waves have become a widely used technique for rapid and long-distance detection of rails due to their long propagation length and wide detection range. The single-guided wave mode shows remarkable signal processing and damage identification prospects. This study proposes a novel excitation method for a unitary guided wave mode in rails with a variable cross-section using semi-analytical finite element and normal mode expansion. This method proposes the optimum location for exciting guided wave mode. Furthermore, the excitation method is verified using finite element simulation, demonstrating its capability to excite a unitary guided wave mode. In summary, the proposed method guides the excitation strategy of a unitary guided wave mode during damage detection and holds the potential for non-destructive testing and structural health monitoring.