Effect of residual stress on the vibration failure of dissimilar steels joint

Elasto-plastic finite element method is used for the welding residual stress calculation in butt welded joint of carbon steel and stainless steel, fluctuating pressure on the ship hull induced by a propeller is calculated from the actual measurement data. As the result of the superposition of vibration load and welding residual stress, the stress amplitude is reduced slightly in high stress area near the welding line, while the value of stress reduction becomes larger when the welding current increases. On the contrary, the stress amplitude is increased clearly far from the welding line. The welding residual stress obviously reduced the fatigue life of ship structure with the vibration load. The fatigue lives of ship structures under vibration are - 1.75 × 105 （ 110 000 ton product carrier） and - 2.43 × 105 （52 000 ton all-purpose cargo ship） without welding residual stress, while the residual stress exists, the fatigue life is down to - 3 × 104.