Fatigue surface crack propagation and intersecting cracks in connection with welding residual stresses. Issue 10 (6th April 2018) - Chernyatin, A.S.
Abstract: The effect of welding residual stress on surface fatigue crack propagation and fracture mechanics parameters of intersecting orthogonal cracks is discussed. The effect of welding residual stresses on fatigue propagation of the internal surface crack is analysed in the case of welded joint of the pipeline. To predict fatigue crack propagation, the modified Forman law taking into account the nonsingular T‐stress as the crack‐tip constraint has been employed. It is shown by means of numerical simulation (the software ANSYS and MATLAB) that welding residual stress and crack‐tip constraint effects lead to the semielliptical form of final configuration of the surface fatigue crack. Fracture mechanics parameters for intersecting surface cracks, namely, circular and semielliptical cracks in welded joint of the pipeline are also analysed by numerical simulation. It was concluded that welding residual stress intensifies the effect of intersecting orthogonal surface cracks on fracture mechanics parameters including the crack‐tip constraint.