NDE Techniques Used in PARENT Open Round Robin Testing

Abstract

This report documents the nondestructive evaluation (NDE) techniques used in the open testing portion of the Program to Assess the Reliability of Emerging Nondestructive Techniques (PARENT), which is comprised of approximately 170 inspections performed on 19 test blocks by 23 teams from Japan, Europe, South Korea, and the USA. The teams examined dissimilar metal weld (DMW) and bottom-mounted instrumentation (BMI) test blocks. The goal of the open portion of PARENT is focused on evaluating the capability of novel and emerging NDE techniques from various entities including both industry and academia. The NDE techniques used in the open testing are broadly categorized as ultrasonic techniques, eddy current techniques, and other techniques. Motivations for developing many of the open NDE techniques can be characterized as addressing one or more of the following challenges:(1) to more accurately characterize large defects, (2) to enable inspections of difficult-to-access regions, and (3) to improve detectability of small defects. Information about the techniques was collected from teams participating in PARENT open testing and is included in the appendices of this report. The information in these appendices is referenced in the main body of the report, which includes brief overview descriptions of the NDE techniques used.

Multiple Wavemode Scanning for Near and Far-Side Defect Characterisation

“…This shows that the range of depth sensitivity depends on the frequency chosen, due to the different Rayleigh wavelengths. Figure 6a illustrates the ray path of the shear wave, showing the shadow region where direct reflections cannot reach the detection EMAT, and no signal is received at the expected arrival time [16]. The crack depth affects the duration of the shadow region, with the depth d related to the length of the region x by…”

“…Where only one side of the sample is accessible, standard inspection may use time of flight diffraction, or phased array techniques [14,15]. For a simple inspection procedure, a modified version of through-transmission using an angle beam probe can be used, where a wave is transmitted into a sample and the blocking of the wave by a far-side defect is imaged [16][17][18][19]. A line-focusing shear-vertical (SV) wave EMAT has recently been proposed for targeting small flaws positioned on the material back wall, using reflections from the defect back to the transducer [20,21].…”