Abstract
Recently, we reported fracture of edge cracked thin metallic conductors upon passing only electric current, i.e., due to the self-induced electromagnetic forces. In this study, effect of simultaneous application of an electric current and a mechanical load on fracture of a thin edge-cracked conductor is investigated. Firstly, finite element method (FEM) simulation was performed to analyze the interaction between stress fields due to the electric current and the far-field mechanical loading. FEM simulations showed that stress fields as well as stress intensity factors due to each stimulus can be linearly superimposed to calculate their respective values under the combined loading. To corroborate the FEM results, experiments were conducted where a mechanical load was applied along with the electric pulse current. The critical current density required to propagate the sharp crack under combined loading decreased and the rate of crack propagation per electric current pulse drastically increased. Effect of mode-mixity on the fracture behavior of thin metallic foil under the combined loading was also studied by applying the mechanical load at different angles relative to the crack, and it was observed that the crack could be deflected at a desired, pre-determined angle by changing the mode mixity.
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Notes
A blow- hole is formed ahead of a crack tip when the liquefied material (due to excessive Joule heating) is thrown sideways by the self-induced electromagnetic force.
It should be noted that self-induced electromagnetic forces always open the crack in mode I (Sharma et al. 2018). Hence, besides the relative magnitude of stress intensity factors due to electromagnetic force and the mechanical load, the mode-mixity is mainly governed by the angle at which the far-field mechanical stress is applied relative to the crack.
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This work was financially supported by Scientific & Industrial Research (CSIR) through a project funded to PK (Grant number CSIR 0366).
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Sharma, D., Reddy, B.S. & Kumar, P. Fracture of pre-cracked metallic conductors under combined electric current and mechanical loading. Int J Fract 212, 167–182 (2018). https://doi.org/10.1007/s10704-018-0298-3
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DOI: https://doi.org/10.1007/s10704-018-0298-3