Productional, Operational, and Theoretical Sensitivities of Fatigue Damage Assessment in Shipbuilding

Abstract

First, this paper summarizes some of the theoretical and practical aspects of fatigue assessments in shipbuilding. The basics of the spectral fatigue analysis procedure for ship structures are mentioned. The simplified procedures are presented in more detail, due to their practical merit. The paper is concerned primarily with the fatigue design procedures used by classification societies, as well as with possible standardizations under the auspices of IACS. Second, an example of fatigue damage assessment for a chemical tanker recently built in Croatian shipyards is provided in order to illustrate and compare the capabilities and differences of available procedures currently used by major classification societies. Finally, parametric studies are performed in order to investigate the effects of productional structural elements misalignment, constructional and fabricational tolerances, of corrosion during operations at sea, shape parameters of theoretical distributions, of selections of the S-Ncurves, and of the combinations of local and global loads. The sensitivity analysis presented here provides suggestions for improving design and production of the critical parts of the ship hull construction with respect to fatigue damage.