Development of an engineering tool to analyze spectral fatigue of floating structures by means of hydro-elastic coupling

Navy vessels are relative long and slender ships which must withstand, during their extensive operational life, cyclic loads produced by the seaway. Fatigue is, hence, for those vessels a dominant parameter in the structural ship design and on their operation. Due to the arising complexity of fatigue assessments, an in-house tool is developed to perform automatized spectral fatigue analysis. Tool is called SEAFALT and stands for Long-Term Spectral Fatigue Analysis. This article described the calculation process of SEAFALT, together with results of a case of study. SEAFALT controls automatically the coupling process of the hydrodynamic load calculated on each sea scenario (via ANSYS AQWA), with its correspondent Finite-Element (FE) structural response (via ANSYS MAPDL). SEAFALT calculates: the expected long-term fatigue damage on each node of the FE-model and the minimum required FAT-class.