EXPERIMENTAL-OBSERVATIONS ON MIXED-MODE FATIGUE-CRACK PROPAGATION

Fatigue crack propagation experiments were conducted on D16AT Al alloy to study the effect of load ratio on mixed mode fatigue crack propaga tion. The experiments were conducted on a Compact Tension Shear specim en at different crack angles in both mode I and mixed mode conditions. At each angle tests were conducted at three different load ratios of 0.1, 0.25 and 0.5. It has been observed that the crack growth rate inc reases with decrease in load ratio. The fracture surfaces were analyse d under the scanning electron microscope. The effect of load ratio was studied in terms of striation spacing.