UCLA

The objective of this work is to develop a versatile nondestructive evaluation (NDE) tool for the design, analysis, and data generation of inspection processes for both metallic and composite pipes. The tool utilizes the waveguide finite element (WFE) method to obtain wave characteristics, including dispersion curves and global functions. The WFE solution is then used in a developed Global-Local (GL) method to model wave propagation in a coupled source-scattering problem. Commercial finite element software is used to obtain the mass and stiffness matrices, as well as to define the geometry of the waveguide and the defect. This feature provides the flexibility to study a variety of defects and multiple material systems. The hybrid WFE/GL solver is validated through benchmark problems, energy-balance calculations, comparisons with Abaqus solutions, and experimental results for both pristine and symmetrically defected cases. This tool allows wave propagation in pipes to be studied in a more fundamental way, where the contribution of each scattered mode can be examined separately, whether reflected, transmitted, or mode-converted. The fingerprints (signals) associated with multiple types of defects, such as cracks and delaminations, can be obtained, allowing an ultrasonic signal library for these defects to be created.