Life Estimation of a Submarine Hull Pressure Based on Fracture Mechanic Approach, in Different Operational Depth Ranges

In this paper, using Fracture Mechanic Approach, the remaining life of a submarine is estimated, and in periodic tests, defects in the structure of its hull pressure were observed. A real submarine is subject of the study, and analyses and simulations are performed to determine the hull pressure of this submarine. For th subject submarine, after modeling and determining some critical areas, a set of assumed defects (cracks with a certain depth) are assumed in the critical area. Then, by defining 15 possible depth scenarios in submarine exploitation, the growth trend of the cracks under the mentioned working conditions is examined and according to the Paris law, the life of the submarine in the presence of these cracks is estimated. Finally, it was concluded that the residual stress intensity factor due to welding processes has a greater share in the overall stress intensity factor entering the structure and will greatly reduce the life of the submarine. It is worth mentioning that Abaqus v 6.14 software was used in performing finite element analyses.