Stein Ove Erikstad

Challenges in computer applications for ship and floating structure design and analysis

This paper presents a review on the key research areas in the design and analysis of ships and floating structures. The major areas of computer application are identified in several stages of ship/floating structure design and analysis with the principal emphasis on the methodologies, the modeling, and the integration of the design and analysis process. The discussion addresses some of the key challenges in computer applications for ship and floating structure design and analysis, and reports on the emerging trends in the research, design and industrial application.

Optimized selection of air emission controls for vessels

In this paper, we consider the selection of air emission controls for a vessel, where the term air emission control is defined as any effort done to reduce the amount of harmful emission to air. Some controls may be interacting with each other in terms of both costs and emission reduction potentials, while others may not be mutually compatible and therefore cannot be used simultaneously. We propose an optimization model for selecting air emission controls for a given vessel, while taking these interaction effects into account. The models objective is to minimize costs while complying with the given emission reduction targets defined by regulations, which are strengthened over time. We use the model to solve a real-life case study with and without taking interactions into account, which demonstrate the importance of these interaction effects on the optimal solution.

Decision Support Framework for Exploiting Northern Sea Route Transport Opportunities

Abstract This paper presents a decision-support model identifying the most viable ice class for a liner vessel transiting along the Northern Sea Route. As input, this model requires parameters, some of which are uncertain. These include the time-dependent length of the Northern Sea Route sailing season and corresponding roundtrip times, the additional capital expenditure and operational expenditure for ice class capabilities for the vessel, as well as fuel price. Furthermore, the sensitivity of the model is discussed on the perspective ice extent, respectively the ice class allowed to enter the Northern Sea Route and possible delays, on the basis of current trend predictions.

Optimized selection of vessel air emission controls—moving beyond cost-efficiency

Shipping currently has an unexploited potential for improved energy efficiency and reduced emissions to air. Many existing air emission controls have been proved to be cost-efficient but are still not commonly installed on board vessels. This paper discusses the so-called ‘energy paradox’ in maritime transportation, presenting barriers to overcome and criteria to consider when selecting cost-efficient air emission controls. Current approaches typically select available controls based on their cost-effectiveness. While this is an important aid in the decision-making process, and, in relative terms, easy to quantify, it is not a sufficient criterion to capture the true preferences of the decision-maker. We present in this paper a multi-criteria optimization model for the selection of air emission controls. This decision framework can also incorporate subjective and qualitative factors, and is applied to the shipping company Grieg Shipping. A survey among internal Grieg Shipping stakeholders identifies the important criteria to consider, their relative importance, and the scoring of the controls. This empirical data is used as parameters in the model and the model is then applied on a vessel of the Grieg Shipping fleet. The results show that nonfinancial factors play an important role in the selection of air emission controls in shipping.

Addressing complexity aspects in conceptual ship design : a systems engineering approach

This research examines the handling complexity aspects of conceptual design. Contemporary consensus suggests vessel design must consider new market requirements such as greater emphasis on environmental performance, a larger degree of uncertainty in terms of contract horizon, and the need for reliability of multiple operations assessed during early stages. Consequently, the industry has experienced development on many levels of ship design, from advanced subsystems (e.g., a wide range of machinery congurations), to vessels with demanding operations (e.g., modern oshore support vessels), to incorporation of eet assessment in early stages. Designers face a number of new technologies - usually representing greater investment - to obtain improved energy eciency and exibility regarding multi-faceted, future scenarios in which the vessel must operate. This large number of options results in an increase in the amount of information that should be considered to understand important aspects of the ship during the conceptual phase. This thesis is based on a systems engineering perspective to approach these kinds of developments, especially recent theories combining complexity theory in engineering.This thesis reviews current methods and approaches that deal with conceptual ship design and its complexity aspects. Based on this review, three research questions are proposed. First, which general complex systems theory premises can be used to dene complexity in conceptual ship design? Second, what general principles for organizing and simplifying complexity t the conceptual ship design task? Third, what methods eciently handle primary complexity aspects during conceptual ship design?The results of this study are the identification of the general principle of handling complexity, based on decomposition and encapsulation, as a strategy to manage relevant information during conceptual design, and proposing a five-aspect taxonomy to characterize and classify complexity in conceptual ship design. The taxonomy categorizes five aspects of conceptual ship design. The structural aspect relates to arrangement and interrelationships of the physical parts in the ship. The behavioral aspect derives from form-function mapping. The external circumstances to which the ship is subjected are captured in the contextual aspect. Uncertainties in future scenarios and expected/unexpected changes over time relate to the temporal aspect. The perceptual aspect relates to how various stakeholders perceive the value they receive from a design through the operational life cycle of the vessel.A discussion of both traditional and novel techniques to handle each of the aspects is presented. Focus is given to methods able to handle the three extended aspects (i.e., contextual, temporal, and perceptual). The goal of the study is to designate ship design as a complex system problem, developing and improving methods capable of handling primary complexity aspects during the conceptual phase.The primary contribution is characterization of conceptual ship design as a complex systems engineering task. Decomposition and encapsulation is presented as a general principle to handle complexity during the conceptual phase of ship design. More importantly, it identifies the intelligent encapsulation allowed by the five-aspect taxonomy, with implementation and development of methods to handle each aspect. Structural and behavioral aspects are investigated, merging traditional and novel techniques. Epoch-era analysis and a ship design deployment problem are used to tackle contextual and temporal aspects. The perceptual aspect is discussed through complex value robustness, and integration and concurrent assessment of all five aspects is handled theoretically through the responsive systems comparison method.This thesis consists of two parts. The first contains an introductory chapter presenting the background, the research questions, state-of-the-art conceptual ship design, ship as a complex system, information growth in ship design and complexity in a systems engineering framework, the research approach, a timeline of the research, initial results of a study of complexity aspects, results relevant to answering the three research questions, discussion of contributions, concluding remarks, and future research. The second part contains the five papers, in which individual results and contributions are discussed in more detail.

Emission allocation problems in the maritime logistics chain

A rational model for emission allocation is a prerequisite for the correct measuring and reporting of the emission footprint in the choice among alternative logistics options. While much attention has been paid to national emission allocations, there has been less focus on cargo-level allocations. In this study, we propose an analytical framework for emission allocation in the maritime logistics chain. This framework provides an entire procedure for the emission allocation of logistics chains with different structures and transported cargoes. A set of universal principles are proposed to form the basis for any rational emission allocation scheme. This includes Completeness, No Redundancy, Simplicity, Fairness, Individual Rationality, Motivation, and Consistency. Three application examples are presented to illustrate this framework: a single logistics chain without return cargo, a single chain with return cargo, and partly uniform cargo with or without return cargo (container shipping). For each of these, different allocation schemes are tested and discussed.

A two-stage optimization approach for sulphur emission regulation compliance

ABSTRACT In this paper, we present a two-stage optimization model for the machinery system selection problem. The objective is to minimize total cost, while aggregated power requirement and emission regulations are constraining the problem. Future fuel prices are considered to be uncertain. From a set of alternatives, the machinery configuration providing the lowest total cost is found. Also design flexibility in terms of future reconfiguration possibilities is taken into account. The machinery selection for a 2000 TEU container vessel is used as an illustrative case. Five initial machinery concepts are considered: diesel machinery, diesel machinery with a scrubber system, dual fuel (DF) machinery, pure gas engines, and a DF ready machinery. There is also a set of reconfiguration possibilities available for each alternative. From solving the case study, DF machinery is found optimal, while pure gas machinery is close to equally good. By solving the problem with deterministic fuel prices, the value of flexibility is not properly accounted for, resulting in an unreasonably high total cost for the flexible machinery alternatives. This demonstrates the need for a decision support approach that explicitly handles future uncertainty, as the two-stage stochastic model presented in this paper does.

A Ship Design and Deployment Model for Non-Cargo Vessels Using Contract Scenarios

Abstract An optimisation model is proposed for the Ship Design and Deployment Problem (SDDP). This model can be used to support the development of the contract specification for non-cargo, service type of ships, facing a set of available contracts or market opportunities with different start-up periods, durations and vessel capability requirements. The proposed model is a binary integer programming (BIP) model, where the problem is to optimally select a design while at the same time considering which future contracts the vessel should be deployed in. Computational study shows that the model is able to solve the SDDP even for large problem sizes. Variants and extensions to the SDDP model are suggested including concurrent selection of multiple vessels (Fleet Design and Deployment Problem), existing initial fleet and forced contract assignment for some of the vessels. Further, generation of contracts and market opportunities for alternative future scenarios can also be considered.

A module configuration and valuation model for operational flexibility in ship design using contract scenarios

ABSTRACT Modularity allows for affordable reconfiguration in operation. Thus, a single modular ship has flexibility and stakeholders have the option to delay investment decisions until more information and technology become available. However, previous design methods for modular ships have not considered the economic benefits of such operational flexibility. We therefore present an optimization model that involves both design and operation decisions related to modules. In creating design alternatives, we use component swapping modularity, in which designs are created by configuring modules to a main body through non-identical interfaces. In evaluation, we represent an operating context based on a set of contracts. We implemented the model in a case study in which both modular and non-modular ships were designed, evaluated, and compared. Moreover, a sensitivity analysis was performed for different contract scenarios. The case study shows that reconfiguration options are influential factors on the value robustness of ships under high uncertainty.

The Influence of model fidelity and uncertainties in the conceptual design of Arctic maritime transport systems

ABSTRACT This paper helps the designer of an arctic maritime transport system (AMTS) to determine an appropriate level of model fidelity with regards to the estimation of transport capacity and ice loading, as well as to understand and manage related design uncertainties. The study is centred around two case studies: 1. The design of an AMTS for independent operation along an arctic route, 2. The design of an AMTS for icebreaker assisted operation along a Baltic route. The outcome of the study indicate that the required model fidelity and the related model uncertainties are case specific. In comparison with the Baltic case, the arctic case required a higher level of model fidelity, and demonstrated a higher sensitivity to uncertainties. In both cases, it proved feasible to mitigate uncertainty with regards to the estimated transport capacity either by increasing the payload capacity of the fleet, or by increasing ship speed.