For accessibility reasons, some specimen may be inspected with a multi-skip ultrasonic beam (multiple skips on the backwall and surface). This ultrasonic multi-skip inspection allows to reach parts far from the probe. Most of the time, a 45° shear wave (SW45°) beam is used in order to avoid mode conversions due to successive skips. L45° wave inspection is less used because it leads to the apparition of several echoes complicating the results interpretation.
CIVA predictions for multi-skip corner echoes of notches located in homogeneous and isotropic flat specimen were compared with experimental results. Two immersion probes were used, a 5 MHz conventional probe and a linear phased array.
The single element probe was used with two angles of incidence in order to generate SW45° and L45° waves. The phased-array was used to generate SW45° in order to focus waves at different sound paths.
Experimental and simulation setup
Results for the 5 MHz single element transducer generating t45 waves
RESULTS FOR THE 5 MHZ SINGLE ELEMENT TRANSDUCER GENERATING P45 WAVES
Results for the 5 MHz phased array probe generating T45 waves with focsusing at different sound paths