Numerical investigation on stress concentration factors of square bird-beak SHS T-joints subject to axial forces

This paper presents a numerical study on stress concentration square bird-beak square hollow section (SHS) welded joints. Both conventional and square bird-beak SHS joints considered have T-shapes and are simply supported at their chord ends. Refined finite element models are developed to obtain the strain/stress concentration factors (SNCFs/SCFs) of square bird-beak joints with various dimensions. The FE models are validated by comparing with the experimental data. The SNCF differences among considered hot spots are analyzed for the identification of critical locations. The influences of three major non-dimensional parameters, i.e., brace/chord width ratio β, chord wall slenderness ratio 2γ, and brace/chord wall thickness ratio_ζ, on the stress concentration factors (SCFs) of square bird-beak T-joints are revealed on the basis of numerous parametric studies. Comparisons of joint types are finally made. The results indicate that, in case of identical non-dimensional parameters, square bird-beak SHS T-joints provide SCFs smaller than conventional SHS T-joints in most occasions, especially when β is small; and SCFs of square bird-beak T-joints are expected to be lower than CHS T-joints with small β and large 2γ and ζ.