Experimental and numerical study on fatigue damage evolution of Q690D welding details

Steel structures are widely used in various types of structures, and welding details, which are fatigue-prone constructions, are typically utilized in steel constructions. In this study, regarding the high cycle fatigue performance and fatigue damage evolution behaviors of high strength steel welding details, experimental and numerical studies have been carried out on two typical types of Q690D high strength steel welding details, including butt-weld connections and cruciform load-carrying fillet weld (CLFW) connections. High cycle fatigue tests have been conducted, SN curves based on effective notch stress have been established and compared with the suggested curves in IIW specification, showing that FAT200 is more suitable for fatigue evaluation of high strength steel welding details. Fatigue damage evolution model and numerical simulation methods for Q690D welding details based on effective notch stress and continuum damage mechanic have been established and validated. Damage evolution analysis of welding details has been conducted based on the proposed numerical simulation method. The simulation method enables accurate characterization of fatigue damage locations.