Grain-scale modeling of anisotropic weld and finite element simulation of ultrasonic propagation: toward a full prediction of echoes and structural noise in weld inspection

Speaker:
Schumm, A.; EDF; France

Authors:
Lhuillier, P.E.; EDF R&D; France
Ferre, A.; EDF R&D; France
Schumm, A.; EDF; France
Shahjahan, S.; EDF CEIDRE; France

ID: ECNDT-0457-2018
Download: PDF
Session: Microstructural Scattering - UT 2
Room: J2
Date: 2018-06-13
Time: 10:50 - 11:10

In service ultrasonic Non Destructive Examination of welds encountered in the primary circuit of nuclear power plants is a major issue for the safety of the installation. The welds exhibit highly anisotropic and complex microstructures which induce beam perturbations and the appearance of structural noise. Numerical modeling is a preferred tool for the prediction of the performance of weld inspections and for the analysis of complex data obtained during these inspections.
In this framework, EDF R&D presents a new simulation approach based on the modeling of the microstructure of a weld. The 2D finite element code ATHENA 2D, developed by EDF, is used to compute the ultrasonic propagation into a realistic (2D) weld microstructure. The grain size, grain orientation map and crystallographic texture were characterized with Electron Backscatter Diffraction (EBSD) measurements. Voronoi-based tessellations are used to create an artificial weld microstructure. This approach enables to reproduce the main phenomena which degrade the inspection of welds: attenuation, beam perturbation and structural noise.
The numerical results obtained with grained scale modeling are compared with both experimental results and with other numerical models implementing coarser weld description.