Question regarding fatigue in AS/NZS 1664.1

[Raffoni]

Hi All,

Section 4.8 of this code describes how to construct an fatigue limit curve given the geometry of the structure. However the aluminium alloy used in the structure is not considered.

I would think the strength properties of the alloy used would have a great affect on the intercept and slope coefficients used to construct the curve. Can it be interpreted that the fatigue limits are conservative enough to apply to any alloy of base material/filler?

I'm asking specifically in regard to a welded structure where the welded areas have a much lower strength than the base material

Thanks

 

[TomLee777]

The fatigue curves for aluminum alloys are very different from steels. Different aluminum alloys also have different fatigue curves. Fatigue properties are material specific; fatigue curves are derived from tests. You need to select a appropriate fatigue curve for the material you use. Structural steels commonly seen in buildings and bridges, however, exhibit similar fatigue behaviors, no matter the yield and ultimate strengths. In most codes and standards, welded structures are grouped into different detail categories.