Analysis of plasticity induced crack closure by the extended body force method (Comparison of various analytical results based on dugdale model)

Abstract

This paper is concerned with the connection between the several analyses of plasticity induced crack closure which have been developed so far based on the Dugdale model. The simulation analysis developed by Newman can leave several stretched elements in the wake of an advancing crack tip. From this simulation analysis, when ΔK is constant the stretched material remaining at the upper and lower crack surfaces becomes constant, and when σ∞ is constant it becomes proportional to the length of the crack. This means that the closure behaviours of the former can be represented by the constant residual stretch model in which the residual stretched material is assumed to by constant along the crack surfaces, and that the closure behaviours of the latter can be represented by the proportional residual stretch model. When the load is small, both the results from the constant residual stretch model and the proportional residual stretch model are close to the results obtained by Budiansky-Hutchinson analysis. Especially, if the stress ratio R 0 and σ∞/σS tends to zero, all results are close to the result of Budiansky-Hutchinson analysis for the case of R=0.