Study of the Residual Stress Effect of Welding Process on the Life Estimation of Submarine

This paper investigated the effect of residual stress due to welding on the submarine remaining life estimation,according to fracture mechanics. After determining the critical zone of the U-100 submarine pressure hulls, that usedby the Germans during the Second World War, by putting the hypothetical cracks in the pressure hulls, the stressintensity factor ,the bending stress intensity factor and the residual stress intensity factor caused by welding processesare calculated. The effect of each stress intensity factors parameters are investigated on the total stressintensity factor. The stress intensity factors and bending stress intensity factors are calculated using finite elementmethod and the results are compared with the calculated analytical results. The results revealed that the finite elementmodel has good accuracy. Then, using the finite element results and the Paris laws, submarine life was calculated.Finally it was concluded that the residual stress intensity factor caused by welding processes has the most portions inthe total stress intensity factor of the structure and it will significantly reduce the life of the submarine. It is notablethat the ABAQUS v 6.14 is used for finite element method.

Keywords:

Submarine , Fracture mechanic , Finite Element Method , Life prediction , Stress Intensity Factor