At the invitation of our college, Associate Professor Qian Xudong from the National University of Singapore (NUS) delivered an academic lecture titled Fatigue of Welded Joints – Enhanced Weld Details and Assessment online via Tencent Meeting on the afternoon of July 22, 2022. The lecture was hosted by Associate Professor Liao Fangfang from the School of Civil Engineering, and a number of teachers as well as more than 10 postgraduate students from the School of Civil Engineering attended the event.
Tubular connections in large-scale engineering structures (such as bridges, offshore structures, and long-span roof structures) often experience cyclic environmental actions, leading to the initiation and propagation of cracks at critical joints. The construction of steel tubular connections requires full penetration of welds, which imposes strict demands on quality control and craftsmanship. To address these practical constraints, Associate Professor Qian Xudong proposed an alternative and cost-effective welding scheme. This scheme aims to provide the full strength and equivalent fatigue performance of the attached components (comparable to full-penetration welds) while featuring small and controllable root discontinuities. The research includes a series of experimental and numerical studies to verify the performance of tubular joints welded using the proposed weld configuration.
The lecture also introduced several enhanced fatigue assessment methods, including the effective notch stress method for welded tubular joints based on extrapolation, the low-cycle behavior of weld details under low ambient temperatures, a method for rapidly determining S-N curves using monotonic tensile test results of high-strength steel, and a unified approach for steel fatigue assessment under combined low-cycle and high-cycle loading.
