Structural design of a container ship approximately 3100 TEU according to the concept of general ship design B-178

Abstract

The initial design stage is crucial for the ship design, including the ship structural design, as the decisions are here taken fundamental to reach design objectives by establishing basic ship characteristics. Consequently, errors which may appear have the largest impact on the final design. Two main aspects related to the design of structures are typically addressed in the initial design: analysis of strength and cost estimation.

The design developed in the dissertation is based on the conceptual design of general containership B-178 built in the Stocznia Szczecińska Nowa, providing its main particulars, hull form as well as the general arrangement.

The general objective of the thesis is to carry out the hull structural design based on the functional requirements of the containership. The design was developed according to the Rules and Regulations of Germanischer Lloyd.

The thesis is started with definition of the structural concept of one complete cargo hold located at midship. At this stage the topology of the structure, which comprises location of primary and secondary structural members, including their material, was carried out by highlighting first the important factors which may affect the dimensioning of structural members such as defining the unit cargo, the stowage of containers inside holds, their securing and handling devices. Afterwards, the numerical structural model was build using the Poseidon ND 11 computer code to evaluate the scantlings of the structural members under the design criteria loads. Two approaches were considered; the first one analytical, where dimensioning of the structural elements has to conform the requirements of the GL rules. The structural mass was estimated, location of centre of gravity, section modulus, moment of inertia, was also calculated. In the second approach direct calculations are carried out with the use of the finite element method to verify the ship hull strength under the selected load cases. It was carried out by introducing the model resulting from the first approach, defining the boundary condition, adjustment of the global load cases and finally the evaluation of the results. Another analysis using the finite element method was made to verify the structural strength of one complete watertight bulkhead subject to flooding. It was performed using another FE model in the GL frame software, based on the beam theory. The evaluation of results indicated the necessity of application of the high tensile steel for the structural elements of the bulkheads.

Drawings of the midship section, bulkheads as well as longitudinal section of one complete cargo hold located in the middle of the ship as well as technical description are also given in the dissertation. The 3D visualisation of a part of the ship located in the middle of the ship using the Tribon software is also presented.