Fatigue Assessment and Testing of a Repaired Tubular T-Joint

Stress concentration factors (SCF’s) for a T-joint were calculated by parametric equations, finite element analysis, weight functions, and by experimental stress analysis. Fatigue life predictions were made on the basis of computed SCF’s. Fatigue tests were performed to determine crack development and fatigue life. Following crack growth through the thickness, the crack was ground out and the joint repaired by welding and improved by peening. Further testing at a 35% higher load showed that the original fatigue life was restored by the repair.