A discrete dislocation model of Stage I fatigue crack growth and an analysis of Mode I to Mode II transition at low ΔK1

V. Doquet

doi:doi:10.1051/jp4:2000625

Numéro		J. Phys. IV France Volume 10, Numéro PR6, April 2000 The Sixth Japan-France Materials Science Seminar JFMSS-6 Microstructural Design for Improved Mechanical Behaviour of Advanced Materials


Page(s)		Pr6-145 - Pr6-150
DOI		https://doi.org/10.1051/jp4:2000625

The Sixth Japan-France Materials Science Seminar
JFMSS-6
Microstructural Design for Improved Mechanical Behaviour of Advanced Materials

J. Phys. IV France 10 (2000) Pr6-145-Pr6-150
DOI: 10.1051/jp4:2000625

A discrete dislocation model of Stage I fatigue crack growth and an analysis of Mode I to Mode II transition at low ΔK₁

V. Doquet

Laboratoire de Mécanique des Solides, UMR 7649 du CNRS, École Polytechnique, 91128 Palaiseau cedex, France

Abstract
Simulations of dislocations nucleation and glide ahead of a crystallographic mode II crack are performed for push-pull and reversed torsion . An influence of the normal stress on the friction of crack flanks, as well as on the condition for dislocation emission is introduced.The crack growth rates are deduced from the dislocation fluxes at the crack tip. A comparison between the loading modes is made. Taking into account the presence of grain boundaries, the repeated decelerations and sometimes the arrest that characterise Stage I crack growth are described by the model. An analysis of the transition from mode I to mode II crack growth observed at low ΔK₁ in single crystals is proposed.