Static, Cyclic, and Fatigue Property Correlations

The results of an experimental and theoretical study relating to the stabilized cyclic state of materials and fatigue are presented. Using the power-law relationships credited to Manson and Coffin, excellent correlations are found to exist between virgin tensile properties and low-cycle fatigue failures for 2024-0 and 2024-T351 aluminum alloys, as well as annealed and hard OFHC copper. Constant strain-range fatigue tests up to a fatigue-life of 10⁴ cycles under axial loading conditions at 3-15 cpm are reported. The elastic and plastic components of strain, as measured from stabilized hysteresis loops are employed with the failure data to derive fatigue equations and the cyclic stress-strain envelope curve for each material.