Assessing accuracy of an efficient analytical-finite element framework for modelling guided wave scattering from corrosion defects in pipes

Modelling guided ultrasound in pipelines is crucial for testing new approaches, understanding physical behaviour, and validating methods in non-destructive evaluation. Fully numerical methods like the finite element method accurately simulate ultrasonic inspections for realistic geometries but are limited by computational memory and processing needs, especially for large structures like long pipes. This work examines the accuracy of a methodology integrating analytical dispersion curves with finite element modelling. Dispersion curves model guided wave propagation over long, uniform sections of the pipe, while finite element modelling handles geometrical complexities such as defects. This integrated model maximises numerical modelling potential without overwhelming computational resources. The method was applied to analyse torsional T(0,1) mode scattering from corrosion defects using a GPU-based FEM solver and Fast-Fourier Transform decomposition of scattered wavefields. The effect of mesh refinement on performance of the integrated model is analysed, considering individual variations in axial, circumferential, and radial element sizes. These findings can significantly reduce the spatial domain needing numerical calculation, enhancing computational efficiency. • Integrated analytical-finite element methods model guided wave scattering efficiently. • Time-domain comparison validates accuracy of integrated method to full finite element. • The accuracy of integrated methods is most sensitive to axial refinement of the local region.