MECHANICAL REASONS FOR PLASTICITY-INDUCED CRACK CLOSURE UNDER PLANE STRAIN CONDITIONS

Authors: Riemelmoser F.O.; Pippan R.

Source: Fatigue & Fracture of Engineering Materials & Structures, Volume 21, Number 12, December 1998 , pp. 1425-1433(9)

Publisher: Wiley-Blackwell

Buy & download fulltext article:

The full text article is temporarily unavailable.

We apologise for the inconvenience. Please try again later.

Abstract:

A mechanical explanation of plasticity-induced crack closure under plain strain conditions is given first by means of dislocation mechanics and then by the methods of continuum mechanics. In plane strain, the event of crack closure is due to transport of material from the wake to the crack tip. It is an elastic effect caused by the response of the matrix surrounding the plastic wake. The transported material produces a wedge which follows the crack tip, and unlike the plane stress condition it does not leave a remaining layer on the crack flanks. The length of the produced wedge at the crack tip is of the same scale as the plastic zone. It is then shown that in spite of its smallness this wedge is able to cause the experimentally observed shielding effect. The results also suggest that the discrepancies concerning the interpretation of fatigue crack growth and closure experiments are likely to be due to differences in accuracy in the detection of such small but nevertheless effective wedges.

Keywords: Plasticity-induced crack closure; Dislocation mechanics; Continuum mechanics; Crack tip shielding

Language: English

Document Type: Research article

Affiliations: 1: Erich-Schmid Institute for Material Science of the Austrian Academy of Sciences in Cooperation with the Institute of Metal Physics of the University of Leoben, A-8700 Leoben, Austria

Publication date: 1998-12-01