Effect of crack propagation on crack tip fields

F.V. Antunes, A.G. Chegini, L.M. Correia, A.L. Ramalho


Crack closure influences fatigue crack growth rate and must be included in the design of
components. Plasticity induced crack closure is intimately linked with the crack tip plastic deformation, which
becomes residual as the crack propagates. The objective here is to study numerically the effect of crack
propagation on crack tip fields. The transient effect observed at the beginning of crack propagation is linked to
the hardening behavior of material. The effect of mesh refinement is studied, and a singular behavior is evident,
which is explained by the sharp crack associated with mesh topology, composed of a regular pattern of square
elements. The plastic zone size measured perpendicularly to crack flank in the residual plastic wake is quantified
and compared with literature models. Finally, the removal of material at the first node behind crack tip with
load cycling was observed for plane strain state and some hardening models in plane stress state.

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DOI: http://dx.doi.org/10.3221%2FIGF-ESIS.25.09