PREDICTIONS OF STRESS-STRAIN CURVE AND FATIGUE LIFE FOR AISI 316 STAINLESS STEEL IN CYCLIC STRAINING

In this study, experimental observations have been performed to understand the cyclic stress-amplitude response, the cyclic hardening/softening characteristics and the cyclic fatigue properties of AISI 316 stainless steel. Based on the experimental observations, these results are found so that the tested AISI 316 stainless steel possesses cyclic hardening characteristics. The shape of the stable hysteresis loop is symmetrical in tension and compression. The Massing cyclic stress-strain behavior is obviously absent. For the case of the absence of the Massing behavior, the power-law type equation is successfully applied to simulate the shape of the stable hysteresis loop at all applied levels of fully-reversed cyclic straining. For the epsilon(a)-based and sigma(max)epsilon(a)-based fatigue life curves, the typical-expressions are developed via cyclic fatigue properties. Besides, a power-law type relationship is also used to develop the fatigue life curve. In contrast to the typical expression, it is found that the power-law relationship is a viable and valid expression in fatigue life predictions. Similarly, the power law relationship is also used to describe the correlation between the cumulative plastic strain energy W-f with the corresponding the fatigue life cycle N-f. Based on the comparison between the predicted and experiment cycles, it is confirmed that the predicted value of W-f calculated on the basis of the simulated hysteresis loop is capable of yielding reasonable life predictions via the W-f - N-f curve.