A method for the evaluation of the fatigue operational life of submarine pressure hulls

In this paper, a method is developed to calculate the fatigue lifetime of submarine pressure hulls, applying linear elastic fracture mechanics, based on the Paris equation. It is known that this structure is submitted to high stresses caused by variable hydrostatic pressure and residual stresses due to the welding process. The association of those variables may cause, after a certain period of time, material fatigue and fracture. Through the application of Parisʹ law, and based on an initial crack size, the crack size after a given number of load cycles, defined by the number of submarine dives, is obtained, furnishing information for possible pressure hull maintenance action, regarding crack repairs.