Elastodynamic Models for Extending GTD to Penumbra and Finite Size Scatterers

The Geometrical Theory of Diffraction (GTD) is one classical method used for modelling edge diffraction. GTD is theoretically valid for canonical infinite edges and diverges around the direction of specular reflection. To deal with finite flaws, 3D incremental models using both GTD and secondary sources have been developed. Experimental validation of these models has been performed. A GTD uniform correction, the UTD (Uniform Theory of Diffraction), has also been developed in elastodynamics in the view of designing a generic model able to correctly simulate both specular reflection and diffraction. Some UTD numerical results are presented.