PSI - Issue 5

Zuheir Barsoum et al. / Procedia Structural Integrity 5 (2017) 1401–1408 Zuheir Barsoum / Structural Integrity Procedia 00 (2017) 000 – 000

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American Welding Society Code AWS D1.1. Fully penetrated joint with under-matched filler material is more ductile and the ultimate strength capacity of base plate can be achieved. It is observed that joints with under-matched filler material are more sensitive to penetration ratio. This influence is more pronounced in joints in S960 steel welded with under-matched filler material. It is also found that the design rules in Eurocode 3 (valid for design of welded joints in steels of grade up to S700) can be extended to designing of welds in S960 steels using correlation factor of one.

Nomenclature f u

nominal ultimate tensile strength of either filler or base material [MPa]

β w correlation factor defined as ratio between tensile weld strength and base material, Table 4.1 in [1]  ┴ normal stress perpendicular to the weld throat [MPa] τ // shear stress (in the plane of the weld throat thickness), parallel to the axis of the weld [MPa] γ M2 safety factor, 1.25 F applied force [N] a weld throat thickness [mm] l length of the weld [mm] α angle between applied load and critical weld throat plane Two types of joints were considered; fillet welds (cruciform joints) and butt welds with full and different partial penetrations. The specimens were designed according to Hobbacher (2007) and SS-EN 9018 (2010). The fillet welds were designed with full (100%) and partial (50% and 75%) penetration. The lower weld in the cruciform joint is always fully penetrated while the upper weld has different penetration levels. Web plates in these joints are made of S600MC HSS grade while the flange is made of S690 QL HSS grade. Three different consumables for various strength mismatch cases were selected based on the properties of the lower HSS grade. For more details on filler material strength and penetration ratio see Khurshid et al (2012). Fig 2a shows the geometry and dimensions for the cruciform joints. For the butt-welded joints, the specimens have been designed for fully and partially penetration. Dimensions of the X and single V butt welds are shown in Fig 2b. The partial penetrated joints were designed with 67% weld metal penetration. The but-welded joints were manufactured in HSS grades S700 and S960. Filler materials for three strength mismatch cases (under-matched, matched and over matched) were selected, for more details about filler materials and welding see Khurshid et al (2015). 2. Static Joint Design

Fig 2. Dimensions and geometry for cruciform fillet welds (a) and butt welds (b).