Structural behaviours of WAAM 316L stainless steel bolted connections under tensile loading

In this study, the structural behaviours of wire and arc additive manufacturing (WAAM) stainless steel bolted connections were investigated. A total of 64 WAAM 316L stainless steel bolted connection specimens with a nominal thickness of 7 mm and 3 mm were examined under axial tensile loads. The geometric dimensions of the specimens were measured using the 3D laser scanning technology, while the entire deformation process of the specimens during the tests was recorded using the digital image correlation (DIC) technology. The influences of key parameters, including the end distance, edge distance, bolt diameter, and WAAM printing direction, on the ultimate capacities and failure modes of the specimens were analyzed in this study. To evaluate the accuracy of the existing design standards, the obtained experimental results were compared against the predicted values by the existing design codes including Chinese code (CECS 410–2015), American code (AISC 370–21), European code (EN 1993-1-8) and American code (AISI S100–16). The comparison results indicated that the average ratio between the experimental results and the design strength predicted by the design codes ranges from 1.00 to 1.20. Among these, the average ratio for AISC 370–21 is relatively accurate. Additionally, the current CECS 410–2015, AISC 370–21, EN 1993-1-8, and AISI S100–16 are all unable to accurately predict the failure mode of bolted connections, with prediction accuracy rates ranging from 37.5 % to 65.6 %. Enhancing the design methods for WAAM-fabricated stainless steel bolted connections remains an essential area for further development.