Ultimate Strength Analysis Of Ship Structure Based On Idealized Structural Unit Method

The ultimate strength of ship structures indicates the limits of their carrying capacity ofships, so, it has always been widespread concern and attention in the field of the shipmechanics. After years of research and development, there are a large number of methods ofhull ultimate strength calculation, in which the ideal structural unit method (ISUM) comparedto other method for calculating has the advantages of shorter time, higher accuracy and so on.Based on the ideal structure element method, the ultimate strength of hull structure will beanalyzed in this thesis. Specific studies are as follows:Based on the theory of the ideal structure element method, three basic elements foranalyzing ship hull ultimate strength are listed in the thesis, namely idealized beam elements,idealized rectangular plate elements and idealized stiffened plate element. What’s more,stiffness of these three elements and the detailed derivation of the formula are given in detailin the thesis.Through the establishment of various failure modes of the element stiffnessmatrix, calculation program for the analysis of ship hull structure ultimate strength iscompiled.Based on the procedure, the ultimate strength of a series of typical box girder models iscalculated. Therefore, the accuracy of the results of the procedure is checked. Taking intoaccount the complexity of the hull structure, the real ship ultimate strength analysis of oiltankers and bulk carriers is carried on. Furthermore, a set of simplified method of calculatingthe ship hull ultimate strength effectively. According to the comparison of process solutions,experimental results and finite element solutions, the rapidity, simplicity and reliability of theprogram is fully demonstrated.Therefore, the method of strength check and strengthassessment in ship structures is available.by sensitivity calculation, several main parameters which influence the ultimate strengthof ship structures are analyzed qualitative. Investigating these parameters on the sensitivity tothe ultimate strength of the ship hull, a further information on the hull design will beprovided.