Measurements of the Near-Tip Deformation in Inhomogeneous Elastic-Plastic Fracture Specimens Using the Moire Interferometry

Abstract

In order to investigate inhomogeneity effects in elastic-plastic fracture, A533B steel and HT80 steel, which have considerably different yield stresses, were chosen. The moire interferometry was used for direct measurements of the crack-tip behavior in the homogeneous CT specimens of A533B and HT80, and in electron-beam-welded inhomogeneous CT specimens of these two materials. Two-dimensional moire gratings with relatively low frequency of 300 lines/mm were used to follow large plastic deformations. The near-tip deformations were compared with the corresponding HRR singular fields. Large inhomogeneity effects were observed in the moire fringe patterns as plastic deformations proceed. © 1993, The Japan Society of Mechanical Engineers. All rights reserved.