Strength Analysis Of Bulk Carrier Based On Finite Element Method

Strength calculating of ship'hull, which is worthwhile for safety, is an important method to improve the safety of voyage, and to reduce casualties due to structure's failure. Generally the hull strength must be assessed at design. Over a period of time, ship's strength is reduced owing to corrosion, wear and fatigue fracture. Hull's strength for the old ships needs assessment if necessary to ensure the navigation safety. Therefore, analysis of hull's strength is an effective methor for both newly-built ships and old ones.Finite element method is a common numerical analysis method, which has been widely applied in ship industry. Now strength assessment is to be carried out in accordance with the rules and guidelines of each main classification society. So direct calculation using finite element method is mandatary and worldwidely used.The hull structure of an offshore 37000t bulk carrier is analysed as an example application, mainly including:based on the Patran/Nastran software, primary structural members of part holds amidship are chosen to build the three-dimensional model. According to the requirements of the Guidelines for Direct Strength Analysis of Bulk Carrier(CCS 2004), load cases, imposed loads and boundary conditions are to be determined, and the hull strength analysis of the ship hull is carried out using FEM. The analysis of primary structural members of the middle cargo hold is the key point. Finally the von Mises are compared with the permissible values.Strength assessment shows that the strength of the ship complies with the requirements of the Rules. During the same period, the load cases are chosen according to the Guidelines, and the imposed load is calculated and adjusted considering the actual operation to remain strength allowance, which is the innovation of the thesis.