Engine Titanium Consortium - Center for Nondestructive Evaluation ...

model parts across 17 micrograph planes (including 4 patches) with 30 boundary traces. The
physical dimension of the minimal “bounding box” in the original orientation of micrographs (also
shown in Figure 1) is 135 (X) x 31 (Y) x 64 (Z) mils. Figs. 2-4 depict the three-dimensional
geometric surface model of the defect. Based on the geometric model results, the corresponding
UT model was utilized to produce the simulated C-scan images as shown in Fig. 5. The overall
agreement between the experiment and model predictions is not as good as for previous cases. As
viewed through sides 5 and 6, the model predictions are low by 5.8 dB and 6.1 dB respectively,
Through side 2, the predictions are high by 8.1 dB. For the CBS, our target agreement is 6 dB,
although we have often obtained agreements on the order of 3 dB. We believe that the differences
observed for this defect are on the high side of the target agreement because of the
aforementioned absence of fiducial marks which made the construction of the solid model less
accurate. As viewed through side 4, the model predictions are high by an unacceptable 15.2 dB.
We believe that this is caused by the aforementioned possibility that part of the beam was “cut-off”
by the curved exterior surface of the sample. Examination of Figure 1 shows that this would have
been most likely to occur for side 4.
Flaw (inside)
Side 1 (top)
Side 2 (back)
Side 5 (right)
Side 6 (left)
Side 4 (front)
Z
Side 3
X
Side 6
Side 2 Side 5
Y
Side 1
Figure 1
Quarterly Report – January 1, 2002 –March 31, 2002
print date/time: 6/6/2002 - 8:39 AM – Page 90