A Study of the Effects of Loading Amplitude and Induced Stress Ratio Stress Ratio on Fatigue Life of a Nodular Graphite Cast Iron Structure Structure Undergoing Multi-Axial Proportional Cyclic Loading

Abstract

This effect is directly related to the maximum Von Mises stress. The latter increases in a linear fashion as R increasesfrom -1 to +1, and exhibits a maximum value at R equals to -1. Also, it is found that fatigue life and Von Mises stress are highly dependent on the induced stress ratio (σ/τ). Von Mises stress increases as stress ratio increases. In a reverse manner, fatigue life increases slowly as the ratio /increases. This result concludes the strong effect, on fatigue life, of the presence of the axial load within the multi-axial cyclic loading. In fact, axial loading favors the mode I crack which propagates rapidly perpendicularly to the axis of axial loading.