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Interaction problems between cracks and crystal defects in constrained Cosserat elasticity

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journal contribution
posted on 27.11.2018, 09:22 authored by Konstantinos BaxevanakisKonstantinos Baxevanakis, H.G. Georgiadis
In this work interaction problems between a finite-length crack with plane and antiplane crystal defects in the context of couple-stress elasticity are presented. Two alternative yet equivalent approaches for the formulation of crack problems are discussed based on the distributed dislocation technique. To this aim, the stress fields of climb and screw dislocation dipoles are derived within couple-stress theory and new ‘constrained’ rotational defects are introduced to satisfy the boundary conditions of the opening mode problem. Eventually, all interaction problems are described by single or systems of singular integral equations that are solved numerically using appropriate collocation techniques. The obtained results aim to highlight the deviation from classical elasticity solutions and underline the differences in interactions of cracks with single dislocations and dislocation dipoles. In general, it is concluded that the cracked body behaves in a more rigid way when couple-stresses are considered. Also, the stress level is significantly higher than the classical elasticity prediction. Moreover, the configurational forces acting on the defects are evaluated and their dependence on the characteristic material length of couple-stress theory and the distance between the defect and the crack-tip is discussed. This investigation reveals either a strengthening or a weakening effect in the opening mode problem while in the antiplane mode a strengthening effect is always obtained.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Journal of Micromechanics and Molecular Physics

Citation

BAXEVANAKIS, K.P. and GEORGIADIS, H.G., 2018. Interaction problems between cracks and crystal defects in constrained Cosserat elasticity. Journal of Micromechanics and Molecular Physics, 3 (03n04), 184001.

Publisher

© World Scientific Publishing Company

Version

AM (Accepted Manuscript)

Publisher statement

Electronic version of an article published as Journal of Micromechanics and Molecular Physics, 3, 03n04, 2019, 184001, https://doi.org/10.1142/S2424913018400118 © [copyright World Scientific Publishing Company] https://www.worldscientific.com/worldscinet/jmmp.

Acceptance date

13/11/2018

Publication date

2019-01-07

ISSN

2424-9130

eISSN

2424-9149

Language

en