Semi-analytical methods for the simulation of the ultrasonic non destructive testing of complex materials

Abstract

During the last decade, the role of the NDT simulation has been continuously increasing and diversifying in all the industrial sectors concerned by complex inspection methods. The UT simulation tools gathered in the CIVA software developed at CEA LIST include beam and defect echoes computations. The propagation of elastic waves is computed using an asymptotic paraxial ray approximation. In the case of some heterogeneous materials, such as polycrystalline structures and welds, it requires the definition of equivalent propagation properties for which several methods have been developed. In the case of fine-grained polycrystals, the propagation is first computed for a homogeneous effective medium. Attenuation filters are applied afterwards and structural noise is modeled as the echoes of a random distribution of scatterers. Their parameters can be set empirically or calculated based on microstructural properties. Polycrystals with coarser grains are modeled using Voronoi diagrams. The propagation in the comp...