Analysis of the time variant reliability of ship hull

Using the property of the monotonic degradation of the ship hull strength with time, the minimum value of the ship hull strength in the design lifetime can be easily determined. Based on it, and with the maximum load in the design lifetime, a new time variant reliability formulation can be established by the classical time invariant reliability method. Compared to Guedes Soares and Garbatov's time variant reliability formulation, which is based on the up-crossing rate of a stochastic process, the new formulation exhibits the continuous decrease of the reliability of the ship hull with time and avoids the tedious numerical integration. The new formulation is computationally efficient.