Study on mechanical properties of wire and arc additive manufactured T-stub connections

The wire arc additive manufacturing (WAAM) technology has a wide range of application prospects in the field of structural engineering, such as high productivity, low equipment costs, high material utilization ratio and excellent environmental sustainability. In order to investigate the mechanical properties of the connection joint of WAAM carbon steel T-stubs, a series of 12 sets of connection joint specimens consisting of WAAM carbon steel T-stubs, high-strength steel (HSS) T-stubs and high-strength bolts were designed. The effects of bolt line position and bolt arrangement on the initial stiffness, failure mode and ultimate bearing capacity of the specimens were investigated by tests. Geometrical parameters of WAAM carbon steel T-stubs were measured by 3D laser scanning technology. Digital image correlation (DIC) technology was used to assist in measuring the displacement response of T-stub connection joints during the loading process. The test results show that WAAM carbon steel T-stubs have superior mechanical properties. As the distance between the bolt line and the web-flange junction decreases, the initial stiffness and ultimate load capacity of the specimens tend to increase, while the failure mode is all the expected flange damage, and the bolts do not fracture. In order to evaluate the applicability and accuracy of the relevant calculation methods by comparing the test results with the calculation results of existing design regulations, comparison results show that the existing design method overestimates the initial stiffness of the specimens, and predicts the damage modes more accurately, but the predictions of the ultimate load capacity are conservative. At last, the existing calculation model was modified, and the modified calculation model predicts the ultimate bearing capacity of the connection joints better. © 2024 Central South University of Technology. All rights reserved.