Finite Element Analysis of Fatigue Crack of Square Bird-Beak X-joints Under Brace Axial Loading

This paper presents a numerical study of the fatigue crack propagation of square bird-beak hollow section welded X-joints. A pair of axial forces were applied at the brace ends, while the chord ends were free. Finite element modelling was done in ABAQUS while FRANC3D was used for the computation of stress intensity factor and crack propagation. The initial crack inserted at the site of maximum stress concentration. Paris' law was used to compute the fatigue life. The results obtained from the finite element analysis compared with the experimental data, and the predicted crack growth was found to be in good agreement with the test observations. For such joints, the surface cracks length vs. fatigue crack growth curve proposed to ensure practicability in real applications.