Title
: Weight Optimization of Marine
Vehicles Based on Structural Analysis Using Finite Element Method
Author :
Moussa Ahmed
Ibrahim Moussa
Collection : M.Sc. Marine
Abstract:
A
ship’s main dimensions decide many of her characteristics, e.g. stability. hold
capacity, power requirements, and more importantly her economic efficiency.
Therefore determining the main dimensions and ratios, and coordinating them in
such a way that a ship satisfies the design conditions forms a particularly
important phase in the overall design. In general, the larger the ship is, the
more economically efficient she is.
The characteristics desired by a shipping company can usually be achieved through various combinations of dimensions, such characteristics could have allowed for an economic optimum design to be achieved if it were not for the restrictions imposed by the size of locks, canals, slip-ways and bridges and most commonly water depth. In addition, other operation relevant factors may influence the determination of an optimum ship size, for instance, the width of containerships is limited by the span of container bridges and port time increases with size which reduces the number of voyages per year and thus the income, hence, a weight reduction of a specific design without altering its main dimensions offers a best possible alternative for the sake of economic efficiency as it allows for more deadweight, higher profitability, less steel and initial building cost, and even less fuel consumption and higher speed in the lightship operating condition. In the light of the above, the structural weight optimization of an offshore supply vessel using the size optimization method is investigated in this thesis. Throughout this thesis an introduction on the physical meaning of the finite element method with an explanation of the nodes and elements concept and role is presented. In addition, the thesis introduces the usage of several computer soft ware's to model, check, load, and analyze a structure. Knowledge on planning for a finite element structural analysis and the responsibility of the analyst are offered in this thesis. The basic concept of structural optimization, and optimization characteristics and methods are elaborated in this thesis.
The characteristics desired by a shipping company can usually be achieved through various combinations of dimensions, such characteristics could have allowed for an economic optimum design to be achieved if it were not for the restrictions imposed by the size of locks, canals, slip-ways and bridges and most commonly water depth. In addition, other operation relevant factors may influence the determination of an optimum ship size, for instance, the width of containerships is limited by the span of container bridges and port time increases with size which reduces the number of voyages per year and thus the income, hence, a weight reduction of a specific design without altering its main dimensions offers a best possible alternative for the sake of economic efficiency as it allows for more deadweight, higher profitability, less steel and initial building cost, and even less fuel consumption and higher speed in the lightship operating condition. In the light of the above, the structural weight optimization of an offshore supply vessel using the size optimization method is investigated in this thesis. Throughout this thesis an introduction on the physical meaning of the finite element method with an explanation of the nodes and elements concept and role is presented. In addition, the thesis introduces the usage of several computer soft ware's to model, check, load, and analyze a structure. Knowledge on planning for a finite element structural analysis and the responsibility of the analyst are offered in this thesis. The basic concept of structural optimization, and optimization characteristics and methods are elaborated in this thesis.
