Optimization and Testing of Wire Arc Additively Manufactured Steel Tubular T-Joints

Tubular joints have been extensively applied in engineering structures because of their superior structural performance. However, welding of conventional tubular joints is problematic, time-consuming, and difficult to ensure quality. Additive manufacturing combined with topology optimization provides an innovative solution to these issues. This paper first presents a complete integrated topology optimization design framework for tubular T-joints. The bidirectional evolutionary structural optimization (BESO) method was employed to optimize the tubular T-joints. The structural performance of the optimized joints in terms of stress distribution, maximum displacement, maximum stress, and compliance was studied through finite element analysis. Subsequently, wire arc additive manufacturing (WAAM) was employed to fabricate two typical optimized joints with intricate geometries and a corresponding prototype joint. Compression tests were conducted on two prototype joints (one made of traditional Q235 steel tubes and one by WAAM) and two WAAM optimized joints. The test results showed that the load-bearing capacity and stiffness of the two optimized joints were superior to those of the prototype joints. The effectiveness of the integrated framework of topology optimization and additive manufacturing was verified. The key features of the structural performance of the WAAM T-joints were examined and discussed.