| ABSTRACT: | EFFECTS OF ACCUMULATED TORSIONAL STRAIN AND DAMAGE ON THE MAGNETIC
PROPERTIES OF STEEL
E.S. Gorkunov, S.V. Smirnov, D.I. Vychuzhanin, and S.Yu. Mitropolskaya;
Institute of Engineering Science; Russian Academy of Sciences (Urals Branch), Ekaterinburg; Russia.
The objective of this study was to investigate the effect of shear strain and accumulated damage induced by
torsion on the magnetic properties of cylindrical steel rods with 0.45% carbon content. At each phase of
loading torque of certain magnitude with no associated bending moment had been applied to the sample and
then removed before the magnetic properties were measured and the achieved strain degree was calculated.
The torque was thereafter repeatedly applied up to the fracture of the sample. The average integral degree of
shear strain accumulated was calculated by taking the summation over all the previous values of the strain
degree. The damage accumulated was estimated by a linear model. Magnetic properties were measured from
the major and minor cycles of magnetic hysteresis. The results obtained reveal analytical relationships for
magnetic coercivity as a function of strain and damage accumulated by material under torsion. The
correlation obtained allows one to evaluate the torsional strain and current damage of metal, as well as to
estimate the residual lifetime of an article under torsion, provided its coercivity is available.
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