Experimental study on failure modes and load-bearing capacities of wire and arc additively manufactured steel bolted connections
The wire and arc additive manufacturing(WAAM),one of the methods of metal 3D printing,has shown significant potential in manufacturing large-scale steel structural elements with reasonable printing accuracy,time and cost in the construction industry.To investigate the mechanical performance differences of WAAM lap shear specimens caused by differences in the manufacturing process and material properties,experimental studies were conducted on the material properties of WAAM steel and the structural behaviours of WAAM lap shear specimens.In this paper,a total number of 24 WAAM lap shear specimens with three different print layer orientations and 72 WAAM lap shear connection specimens with different design configurations were fabricated,dimensionally measured with the 3D scanning technique,and subjected to tensile coupon tests and lap shear connection tests.The failure modes and load-bearing capacities of the bolted connections were analysed,focusing on the print layer orientations of the WAAM steel plates.The current code design provisions and design approaches proposed in the literature for steel structures were further evaluated by comparing the failure modes and load-bearing capacities of the bolted connection specimens.This research shows that both the material tensile specimen and the bolted connection specimen show anisotropy in the test,and the difference in bearing capacity reaches 10％and 20％respectively.The material anisotropy has a certain impact on the failure mode.The relatively accurate predictions of the capacity of the WAAM lap shear specimens following the current steel design standards are significantly compromised by not predicting failure modes correctly,which could be attributed to the influence of anisotropic material properties of the WAAM steel plates and the failure modes of tilt-bearing and end-splitting which are not considered in current design provisions.
bolt connectionwire and arc additive manufacturingmetal 3D printingfailure modedesign approachultimate capacity
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