Originally published June 5, 2018 at the Non-destructive Evaluation of Aerospace Materials and Structures conference.
in industry has a vital role in assuring integrity of assets and safety for people and environment.
Friction Stir Welding (FSW) is among the welding technique aerospace industry uses. It is used in a range of industries including military, naval, and rail. FSW allows for rapid and high quality welding of previously difficult to weld materials such as 2XXX and 7XXX aluminum alloys, among the others. Phased Array (PA)
has been proven effective in inspecting FSW and most of the aerospace companies have it among their advanced NDE techniques, but improvements in characterization of defects may help.
The new Full Matrix Capture (FMC)
family of ultrasonic imaging measurements is showing great potential and is considered the natural evolution of PA. The majority of FMC techniques in the market uses a single array probe with only one acquisition mode at a time and has slow data processing. Inverse Wave Extrapolation (IWEX)
is a fast processing technique for FMC data that uses two array probes and up to 13 simultaneous acquisition modes, with each mode providing a different inspection angle of an anomaly. With this paper we describe the IWEX technique and share the results and benefits of using it over PA, such as straightforward interpretation including automation of identification and sizing of indications, flaws and defects.
PA is the ultrasonic inspection method currently used to inspect FSW. Although it represents a remarkable advancement compared with the single UT (Ultrasonic Technique) A-Scan, it still has some limitations i.e. focusing depth and difficulty to show vertical features, making interpretation something for highly skilled and very experienced personnel. IWEX belongs to the FMC family of ultrasonic imaging techniques and, although it makes use of array probes, it creates the images differently than steering the beam and stacking multiple A-Scans together: it still makes use of A-Scans but it combines all of them to build every single point of the final image that resembles the cross-section of the volume under examination. For this paper, both PA and IWEX have been used to see how each of the techniques images the flaws in FSW samples.