Abstract
NDE of complicated surface defect which is composed of two defects with different depths crossing each other has been demonstrated using photoacoustic (PA) microscope. In the present study, simulated intersecting defects are fabricated on specimen surface by mechanical processing, the defect depths of which are ranging 0.5 - 2.0mm in increments of 0.5mm. The measured PA signal of the intersecting surface defect was processed and displayed as an image. Furthermore, the identification of each detected defect and the depth profile was examined with PA signal intensity distribution. The results show that PA method is useful to detect intersecting surface defect which is difficult to detect by the present NDE techniques, and a marked increase in the irradiated area and the edge effect caused by the presence of four corners at the crossing of the orthogonal defects was observed.
