Computational models for the structural crashworthiness analysis of fixed type offshore platforms in collisions with an offshore supply vessel

Offshore supply vessels (OSVs) regularly visit offshore jacket platforms to transport supplies such as food, equipment, and chemicals. In the past, a number of collisions between supply vessels and offshore platforms have been recorded. As a result, the platform has to design against such potential accidents. Often structural consequences involve highly complex and nonlinear failure mechanisms such as denting, crushing, fracture, and permanent deformation. To capture realistic collision scenarios using numerical analyses such as nonlinear finite element analysis (NLFEA) software, a careful application of modelling techniques is required. The main aim of this study is to develop practical modelling techniques for numerical analysis of collisions between a ship and fixed type offshore platforms. This includes deformations of both ship and offshore platform, dynamic characteristics of the material such as strain rate and dynamic fracture strain, and the influence of the surrounding water. Details of the numerical computations are documented, and the results of the analysis were compared with the various analytical and design recommendations. The applicability of the techniques was demonstrated using an applied example consisting of collisions between an OSV and a jacket-type offshore platform. Further, a sensitivity analysis was carried out for different collision load parameters such as collision velocities and impact locations with varying membrane thickness. It is believed the findings and insights obtained in this study are highly useful for numerical analysis of various collision scenarios within the framework of collision risk assessment study.