Electrical Resistance of Wires with Large Strains

Abstract

SOME time ago, K. H. Swainger¹ directed attention to the remarkable linearity of the electrical resistance of 'Minalpha' wires with large strains, optically measured. As this observation has important consequences on strain measurements, it seemed worth while to examine wires of other materials for the effect. Preliminary experiments showed that for all materials tested the specific increase of the electrical resistance was approximately equal to twice the specific elongation of the wire, if well above the yield point. This result made it obvious that the change of the electrical resistance is mostly a geometrical property, and was not due to a change of the resistivity of the material.