Low cycle fatigue evaluation of welded structures with arbitrary stress-strain curve considering stress triaxiality effect

In this work, load-controlled low-cycle fatigue tests of butt and lap joints are conducted, and a structural strain range parameter is proposed to characterize the fatigue behavior of weldment. A new scheme to calculate the structural strain range is formulated, which can deal with arbitrary material elastic-plastic behavior. The method captures the lateral structural constraint effect through the stress triaxiality parameter. The new fatigue parameter shows superior data transferability, which correlates high and low-cycle fatigue data of steel, aluminum, titanium, and magnesium weldments into one master E-N curve.

Automated summary

This work conducts load-controlled low-cycle fatigue tests on butt and lap joints, and proposes a new structural strain range parameter to characterize the fatigue behavior of weldments. The new method, which can deal with arbitrary material elastic-plastic behavior, captures the lateral structural constraint effect through the stress triaxiality parameter. The new fatigue parameter shows superior data transferability, correlating high and low-cycle fatigue data of steel, aluminum, titanium, and magnesium weldments into one master E-N curve.