Semi-analytical hybrid modeling of wave propagation for high-efficiency ultrasound inspection in large plate-like structures

The propagation characteristics of Lamb waves in structural waveguides provide valuable insights into the health of a structure. As these waves travel through the medium, they are reflected or scattered by structural boundaries, discontinuities, and defects. This study introduces a fast and efficient modeling approach for Lamb wave propagation in large, built-up, plate-like structures, aimed at supporting damage localization in realistic scenarios. The proposed methodology combines a semi-analytical modal pencil approach with the wave finite element (FE) and hybrid FE/wave FE methods. This framework enables accurate simulation of transducer-excited ultrasonic fields, transient guided wave propagation, and wave interactions such as scattering and reflection at defects, interfaces, and boundaries. Importantly, the computational cost of this method is independent of the propagation path length, making it particularly suitable for long-range inspection tasks. Case studies include isotropic plates joined by both flat and bent connectors. The model’s accuracy is validated through comparison with time-domain 3D FE simulations. Furthermore, the practical capability of the proposed approach is demonstrated via experimental damage localization in a real bent aluminum plate. The results highlight the potential of this digital twin framework to enhance the damage detection capabilities of ultrasound-based structural health monitoring systems, while requiring only a minimal number of actuator-sensor pairs.