Motion and structural analyses of a drillship under hurricane conditions and ice impact loading

The goal of the study is to understand drillship structural behavior under extremely hazardous hurricane conditions, as well as the variables influencing their strength and stability. In the present study, two cases are considered: a drillship is analyzed under sea states of severe storm conditions using hurricane data from the Gulf of Mexico, and ice loads acting as impact loads. Studies show that the drillship experienced instability caused by the excessive roll and pitch response motion. The critical design shear stress and longitudinal bending moment are predominantly affected by the amplified pitch response in the moonpool. The results illustrate details of the motions induced by environmental loads, free float tests, a combination of hydrodynamic diffraction and Froude-Krylov forces, impact analysis, and RAO-based time and frequency domain studies. These are very useful insights for the design of drillships under impact loads.