Continuing crack-tip deformation and fracture for plane-strain crack growth in elastic-plastic solids

Abstract

ANALYSIS of the deformation field consistent with a Prandtl stress distribution travelling with an advancing plane-strain crack reveals the functional form of the near tip crack profile in an elastic-plastic solid. The crack opening 6 is shown to have the form 6 N r In (const./r) at a distance r from the tip. This observation coupled with data generated from finite element investigations of growing cracks in small-scale yielding permits the construction of a relation characterizing the deformation at an extending crack tip. A ductile crack-growth criterion consisting of the attainment of a critical opening at a small characteristic material distance from the tip is adopted. Predictions of the stability of a growing crack for both small-scale yielding specimens and those subject to general yielding are discussed.

Strip Yield Model Numerical Application to Different Geometries and Loading Conditions

“…The 45-degree intercept proposed first by Rice [3] to be the opening distance where 45 ° lines from where the crack tip intercept the crack faces, is commonly used in Finite Element Analysis to infer CTOD measurements. Some researchers however have used the first node behind the crack tip to compute the crack opening levels [4,5,6].…”

Fracture propagation in DWT back slotted specimens

“…CTOA represents a very interesting parameter since is directly related to the geometrical aspect of the specimen in the region near the crack tip. According to many researchers it can be used for evaluating critical material conditions for crack propagation (Azodi et al, 1990;Rice et al, 1978;Wang et al, 1994). CTOA is the angle emerging from the opening crack flanks.…”

Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

“…A propagating crack experiences non-proportional deformation in the active plastic zone ahead of the crack tip as well as a region of elastic unloading behind the advancing crack tip [94,95]. This region of elastic unloading leaves behind a wake of residual plastic deformation and results in a different strain distribution at the propagating crack tip relative to a stationary crack tip [94,95].…”

“…This region of elastic unloading leaves behind a wake of residual plastic deformation and results in a different strain distribution at the propagating crack tip relative to a stationary crack tip [94,95]. Namely, strains decay with 1/r ahead of a stationary crack but only with ln(1/r) ahead of a propagating crack in steady state, where r refers to the distance from the crack tip [95]. Therefore, at a fixed value of K and at a given position ahead of a crack, the strain is lower for the propagating crack relative to the stationary crack.…”