i know elctric current passes through least or minimum resistance path. According to relation I= (V/ rho)(A/L) , the bending of nano or moicro wires slightly/minutly change A &L and so does current, I am looking for some backup to make my argument strong. I tried to find this in the literature but was not able to get a clear picture so if somebody can sufggest or comment....thanks
Dear Imran; In anisotropic materials, the direction of the local current intensity which is a vectorial quantity depends on the scaler product of local conductivity tensor and electrostatic field intensity that is also vectorial quantity.
What you are talking about macro behavior of a conductor having isotropic character which is exposed deformation by bending having slight change in cross section and length. If one would have a little knowledge on elasticity theory one should realized that one has to set the boundary conditions first. See: Theory of Elasticity by Timoshenko & Goodier, Chapter 12. (Bending of a Cantilever Bar circular cross section). Actually regardless the applied moment to the free edge the shape of the cross section after the bending doesn't change, only upper edge halve would be under tension and lower halve under compression. The shear stresses acting on the cross sections are uniform. Intensities these normal stresses depend upon the distances from the center line of the bar X and Z which is measured from the fixed edge of the bar. SigmaZ = -P(L-Z)X /L. Where P is applied force, L is length of bar.
That means there is no change in the cross section but extension on the upper halve and contraction on the lower part of the longitudinal central section of the wire. That means there is a current crowding at the inner halve intensity of which increases with the distance from the center, and decreases with the distance from the fixed edge. The maximum current crowing occurs at the lower surface of the wire where it is attached to the fixed holders.
@ Tarik Ömer Oğurtani.....pretty good, but what you expect as net rate of current?I mean is there change in resistance during the flow of current? I think, in midle portion , due to crowdness of chargess , there will be a higher resistance as compare to end parts. Consequently, a variation in electrical resistance will be observed.
My guess is that; if the bending is in the elastic range that means there is no formation and motion of dislocations and other structural defects, then there shouldn't be any over all resistance change other than the specimen clapping-edges- regions, which are always subjected to local plastic deformation.
In the case of plastic deformation situation would be different and one should expect resistance increase as long as the specimen is below the polygonization temperature.
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