Dissertação

{pt_PT=Risk based ship hull structural design and maintenance planning} {} EVALUATED

{pt=Objective of this work is to develop a tool for a multi-purpose vessel that estimates optimal ship specifications, defines the optimal scantlings of the midship section and finds out the optimal maintenance strategy. The measure parameters for the optimization tasks are the cost, aiming to a consistent model that, based on structural safety, is the most convenient for the ship owner. The first task, through an optimization algorithm, finds the minimum of the Required Freight Rate by changing the design variables (Lpp, B, D, T, Cb, Vs), taking into a consideration of constraints related to the ship’s operational profile and stability. Employing MARS2000 software, a typical midship section of a multi-purpose vessel has been designed and the ultimate bending moment is evaluated. The second task aims the optimization of the scantlings through the First Order Reliability Method, in which the probabilistic variables of the wave-induced, still water and ultimate bending moments and the respective model uncertainty factors are accounted for in the limit state function, that defines the bounds for the failure of the ship. The estimated reliability indexes are used to calculate the risk-associated costs being possible to find out its minimum. The third task consists of analyzing six different maintenance policies, which, considering different levels of corrosion tolerances and repair consequences, define the optimal strategy based on the costs, downtime and availability., en=Objective of this work is to develop a tool for a multi-purpose vessel that estimates optimal ship specifications, defines the optimal scantlings of the midship section and finds out the optimal maintenance strategy. The measure parameters for the optimization tasks are the cost, aiming to a consistent model that, based on structural safety, is the most convenient for the ship owner. The first task, through an optimization algorithm, finds the minimum of the Required Freight Rate by changing the design variables (Lpp, B, D, T, Cb, Vs), taking into a consideration of constraints related to the ship’s operational profile and stability. Employing MARS2000 software, a typical midship section of a multi-purpose vessel has been designed and the ultimate bending moment is evaluated. The second task aims the optimization of the scantlings through the First Order Reliability Method, in which the probabilistic variables of the wave-induced, still water and ultimate bending moments and the respective model uncertainty factors are accounted for in the limit state function, that defines the bounds for the failure of the ship. The estimated reliability indexes are used to calculate the risk-associated costs being possible to find out its minimum. The third task consists of analyzing six different maintenance policies, which, considering different levels of corrosion tolerances and repair consequences, define the optimal strategy based on the costs, downtime and availability.}
{pt=Projeto conceptual, fiabilidade, risco, degradação, manutenção, en=Conceptual design, reliability, risk, degradation, maintenance, model}

Julho 11, 2017, 18:0

Publicação

Obra sujeita a Direitos de Autor

Orientação

ORIENTADOR

Yordan Ivanov Garbatov

Departamento de Engenharia Mecânica (DEM)

Professor Associado