Bibliothèque d'Applications

Angle beam ultrasonic units are used for nondestructive testing (NDT) of solid objects, such as metal pipes. They are especially useful for detecting flaws in and around welding areas, such as pores, small cracks, lack of fusion, etc. Angle beam NDT is often used where the straight beam testing struggles to find defects, for example, when the cracks are vertical and thin and thus not detectable because of small amount of reflection. The operating principle of angle beam NDT lies in the conversion of a longitudinal (compression) wave sent by the transducer into a refracted shear (transverse) wave in the test sample. The shear wave is then reflected by the flaws in the test object. Compared to longitudinal waves, shear waves have lower attenuation and shorter wavelength, which makes them capable of detecting smaller defects.

In this tutorial, the Elastic Waves, Time Explicit physics interfaces is used to model wave propagation in linear elastic media. The interface solves the linear elastic wave equation written in the velocity-strain form using the discontinuous Galerkin finite element method (dG-FEM) and an explicit time integration scheme. This approach is well suited for solving large-scale transient problems. The piezoelectric part of the transducer is modeled with the Piezoelectric Effect, Time Explicit multiphysics feature that couples the Elastic Waves, Time Explicit and the Electrostatics physics interfaces. The model takes advantage of a geometry assembly and a nonconforming mesh.