Failure of thin metallic conductors under electric current loading: Transition from sharp crack to blow-hole

Sharma, D and Kumar, P (2019) Failure of thin metallic conductors under electric current loading: Transition from sharp crack to blow-hole. In: Engineering Fracture Mechanics, 208 . pp. 221-237.

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Abstract

Electric current surges of high densities, e.g., >109 A/m2, may lead to failure of pre-cracked metallic conductors by propagation of either sharp crack due to self-induced electromagnetic forces or blow-holes (akin to blunt cracks) formed at the crack tip. In this paper, we discuss controlling transition from sharp crack propagation to formation and propagation of blow-holes in an edge cracked conductor by manipulating current density and crack length. Experiments revealed that a transition from sharp crack to blow-hole occurs when either the crack length was large or the current density was very high. Particularly, crack length and the current density have a symbiotic relationship, wherein an increase of one reduces the critical value of other required for blow-hole formation. Herein, the role of the heat affected zone (HAZ) ahead of the crack tip in the transition from sharp crack propagation to blow-hole formation was ascertained using the finite element method. It is proposed that the extent of HAZ, which depends on the crack length and the current density, directly controls the probability of formation of blow-holes and its size. Alike crack propagation, the blow-holes also propagated in predictable fashion under repetitive electric current pulse loading, thereby paving a path for using this phenomenon for cutting a material. © 2019 Elsevier Ltd

Item Type:	Journal Article
Publication:	Engineering Fracture Mechanics
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to Elsevier Ltd.
Keywords:	Crack propagation; Crack tips; Current density; Heat affected zone, Blunt crack; Crack length; Critical value; Electric current pulse; Electromagnetic forces; Hole formation; Metallic conductor; Symbiotic relationship, Loading
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	13 Dec 2022 04:37
Last Modified:	13 Dec 2022 04:37
URI:	https://eprints.iisc.ac.in/id/eprint/78316

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