SMIME, Fatima-Zahra; Vallourec Centre de Recherche; France
Deneuville, F.; Vallourec Research Center France; France
Duquennoy, M.; Université Lille Nord de France; France
Ouaftouh, M.; Université Lille Nord de France; France
Smime, F.-Z.; Université Lille Nord de France; France
Session: Mathematical Modelling - UT
Time: 16:00 - 16:20
Currently, online UT sanction is done with a standard threshold on ultrasonic echo amplitude, assuming this information is sufficient to estimate the depth of the defect. However the accuracy of the correlation between echo amplitudes and the real depth of defects is not always ensured, especially for tilted (disoriented) defects. Nowadays, simulation is an efficient support to evaluate influencing parameters in order to enhance the selectivity of the UT inspection and offer the possibility to have a better and faster quality loop in our process. In this regard, a two-dimensional UT simulator based on ray theory was developed to describe scattering phenomena in a plate specimen (describing the transverse configuration of pipe UT testing), with surface-breaking defects irradiated by a shear beam. The defects could be right angled or tilted and of different depths close to the inspection wavelength. The simulator provides UT images comparable to those obtained by means of trials and comprises several approaches to describe diffraction based on High-Frequency approximations as well as integral considerations. Comparisons between simulated and experimental results show that High-Frequency approximations fail for tilted defects where no corner echo is observed, whereas approaches based on integral considerations are more accurate but time-consuming.