Simulation of Cyclic Stress-Strain Curve and Stable Hysteresis Curves for Fatigue Life Predition of 304 Stainless Steel

Y.-C. Chiou, C.-M. Tan, and J.-K. Yang (Taiwan)

Keywords

Cyclic stressstrain curve; Branch of stable hysteresis loop; 304 stainless steels; Fatigue life

Abstract

An expression is developed to describe the cyclic stress-strain curve based on the hypothesis that the stress strain coordinates of the upper and lower branches of the hysteresis loop are symmetrical about an imaginary line drawn between the origin and the tip of the loop. Additional, in accordance with the given hypothesis, a set of stress-strain relationships is also presented to simulate the tensile branch of the stable hysteresis loop. Furthermore, theoretical plastic work is calculated by integrating the area within the constructed hysteresis loop. It is noted that the mathematical derivations are performed in accordance with the endochronic theory of plasticity. The accuracy of the proposed set of stress strain relationships is verified by conducting fully reversed constant strain amplitude fatigue tests on the 304 stainless steel. Regarding the symmetry of the stable hysteresis loop, the hypothesis is confirmed by experimental data. The experimental and simulation results are found to be in good agreement, hence confirming the accuracy of the analytical stress-strain relationships. The theoretical plastic work calculated is employed to predict the fatigue lives of the 304 stainless steel via plastic-work-life curves. Again, a good agreement is found between the two sets of results.

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