Stress-Strain Curve of Mild Steel in the Initial Stage of Cyclic Loading

Abstract

Cyclic uniaxial tension-compression tests with various constant strain amplitudes were performed on mild steel to investigate the change of stress-strain curve in the initial stage of cyclic loading. Strain amplitude was nearly equal to a half of the corresponding prestrain. In order to apply the result obtained to a cyclic elastoplastic analysis, the stress-strain curve in each half cycle was fitted by a polynomial, whose coefficients were examined in relation to the number of half cycles and the magnitude of prestrain. An approximate expressioin for the curve in any half cycle was obtained as a function of the number of half cycles, magntidue of prestrain and coefficients in the expression for the first half cycle after the initial loading.