A Treatment of Inelastic Deformation Around a Crack Tip due to Microcracking

TLDR: In this paper, a numerical procedure is described for modeling the number and distribution of microcracks around a crack tip as a function of the applied stress intensity, and the results indicate that texture can strongly influence the slope of the R curve, and that a positively sloped R curve can be produced by the operation of micro-cracking mechanisms.

Abstract: A numerical procedure is described for modeling the number and distribution of microcracks around a crack tip as a function of the applied stress intensity. The procedure accounts, approximately, for microcrack-microcrack and microcrack-crack interactions. Starting with an array of sites where microcracks can form, the model computes the generation rate of microcracks with increasing stress intensity. The interaction between several neighboring sites leading to extension of the main crack is also apparent and, as a result, an R curve emerges from the calculation. The effects of changing the nature of the microstructural variables inserted into the model can be examined; the results of several calculations with differing microstructural properties are compared. These variables include texture and the statistical distribution of strength over the microcrack sites. The results indicate that texture can strongly influence the slope of the R curve, and the calculations demonstrate that a positively sloped R curve can be produced by the operation of microcracking mechanisms.