Stress biaxiality-based residual stress assessment in welded T-joints using the blind-hole method

The blind-hole method is widely used to measure the welding residual stress (WRS) in welded steel structural connections such as T-joints. To enhance the test accuracy, a rapid WRS evaluation method considering stress level and biaxial stress ratio was developed and validated. The proposed method was applied to measure the WRS distributions of T-joints in steel truss bridges, and a finite element model (FEM) simulating the WRS was verified by the test results. On this basis, the effects of welding parameters and geometric configuration of T-joints on WRS were analyzed by the validated FEM. The results show that the maximum error from ignoring the hole edge plasticity or stress biaxiality is about 20%, and the proposed method can effectively reduce the WRS measurement error caused by the above factors. The results of the experiment and FE analysis demonstrate that the WRSs in T-joint are in an obvious biaxial stress state, which further proves that it is necessary to consider stress biaxiality in calibration for the blind-hole method.