Evaluation of crack profiles by Bando et al. - Application of COD-results from FE computations

In an earlier Report we dealt with COD-measurements on water-soaked cracks as are available from literature. In this early note, the effect of damage by the water-glass reaction was addressed and for the COD-field the J-integral was adopted for zones ahead of a crack tip showing an elastic module different from that of the bulk. In the present study we apply results of Finite Element (FE) computations to the same problem.
From our FE-computations on crack-flank displacements it was found that the effect of a reduced Young’s modulus is visible only in a crack-tip distance as is comparable with the height of the crack-tip zones.
The purely elastic calculations by FE lead to COD profiles, which seem to result in a blunting behavior. This suggests a typical elastic-plastic material behavior to the viewer.