Fatigue Analysis of the Effects of Incomplete Penetration Defects on Fatigue Crack Initiation Points in Butt-Welded Members

초록

Fatigue life evaluation of steel structures is a very important issue in their design and maintenance. For steel structure maintenance, it is particularly important to know when and where fatigue cracks are initiated in aging steel bridges. To calculate the fatigue life and identify crack initiation points in butt-welded members, a fatigue finite element method was developed in this study. First, to represent weld fatigue phenomena, this study applied the finite displacement theory and elastic-plastic cycle hysteresis constitutive model to reproduce large deformations and repeated load phenomena. Then, the damage mechanics theory was applied to reproduce fatigue cracks and assess the fatigue life. The effect of incomplete penetration defects on fatigue life and crack initiation points of butt-welded members were clarified using fatigue finite element method. Results also showed that crack initiation points and fatigue life were different depending on the depth of incomplete penetration. The FEM results were considered reliable after comparing with results from Hotspot stresses, IIW and DNV-GL.

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