Shanshan Fu

Towards a probabilistic model for predicting ship besetting in ice in Arctic waters

Abstract Recently, the melting of sea ice due to global warming has made it possible for merchant ships to navigate through Arctic Waters. However, Arctic Marine Transportation System remains a very demanding, dynamic and complex system due to challenging hydro-meteorological conditions, poorly charted waters and remoteness of the area resulting in lack of appropriate response capacity in case of emergency. In order to ensure a proper safety level for operations such as ship transit within the area, a risk analysis should be carried out, where the relevant factors pertaining to a given operation are defined and organized in a model. Such a model can assist onshore managers or ships’ crews in planning and conducting an actual sea passage through Arctic waters. However, research in this domain is scarce, mainly due to lack of data. In this paper, we demonstrate the use of a dataset and expert judgment to determine the risk influencing factors and develop a probabilistic model for a ship besetting in ice along the Northeast Passage. For that purpose, we adopt Bayesian belief Networks (BBNs), due to their predominant feature of reasoning under uncertainty and their ability to accommodate data from various sources. The obtained BBN model has been validated showing good agreement with available state-of-the-art models, and providing good understanding of the analyzed phenomena.

Risk influencing factors analysis of Arctic maritime transportation systems: a Chinese perspective

ABSTRACT Recently, the melting of Arctic sea ice and development of maritime technology are enabling the regular voyages in Arctic waters. However, the Arctic maritime transportation system (AMTS) is a complex and dynamic system with respect to human, technical, environmental and organizational issues. For example, ships operating in Arctic waters suffer severe weather conditions, fully and partially ice-covered waters, and are also difficult to search and rescue in ice-covered Arctic waters due to remoteness from lands. These risk factors will influence the safety and security of ships operating in Arctic waters. For this, this paper identifies potential risk influencing factors (RIFs) for the AMTS from human, technical (ship), environmental and organizational aspects. An analytical hierarchy process (AHP) method is used to analyze the hierarchical relationships and calculate the relative importance of the selected RIFs. Due to the complexity and uncertainty involved in the comprehensive analysis of RIFs for the AMTS, fuzzy sets are incorporated into AHP analysis to represent and treat the epistemic uncertainty. The identified critical RIFs in this study can be used to propose specific guidance for the operations of crews on board, ship owners, and ship managers.

Use of FMECA Method for Leakage Analysis of LNG Fueled Vessels

Liquefied natural gas (LNG), a cleaner energy resource compared to heavy fuel oil (HFO), has been utilized as an energy source by vessels of various types, e.g., ferries, cargo vessels and platform supply vessels (PSV), notably after the release of International Maritime Organization (IMO) interim guideline MSC. 285(86) which officially authorized the natural gas as a marine fuel for merchant vessels in June 2009. LNG fuel is expected to have a promising prospect in green shipping industry with advantages in decreasing the emissions of NOX, SOX, and particulate material. However, as an inflammable and explosive energy source, safety issues of LNG should also be taken into account, especially under the circumstances of fuel leakage during a long voyage. In this paper, failure mode, effects and criticality analysis (FMECA) is conducted for the study on leakage failure modes of LNG fueled vessels. The criticalities of LNG leakage modes are calculated and ranked by taking failure rate, causes and effects (consequence probability and associated severity) of each failure mode into consideration. Event tree analysis (ETA) approach is utilized to identify possible failure consequences and estimate associated probabilities of occurrence, while computational fluid dynamics (CFD) modeling and simulation are applied for the consequence analysis of each failure mode. A typical Chinese LNG powered cargo ship in the Yangtze River is studied for critical leakage modes identification and risk control options (RCOs) provision so as to provide recommendations on the daily operations and safety managements of LNG fueled vessels.© 2014 ASME

Safety assessment of LNG carriers based on fault tree analysis

The consumption rate of LNG has increased rapidly in recent years, which draws the demand for LNG carriers. Over the past ten years, the number of ongoing LNG carriers has increased dramatically while more carriers are expected to be built in the years ahead. This has led to public concern about the safety of the LNG carriers. In this paper, an overall risk identification for LNG carriers is conducted considering the hazards of LNG as a marine fuel and specific hazards to LNG carriers. Based on this, Fault Tree Analysis has been utilized for risk assessment of LNG carriers. By doing so, this paper provides important reference for shipping management authorities and policymakers on developing effective measures to control the identified hazards, so as to improve the safety level of LNG carriers.

Consequence Analysis of LNG Leakage Accident Based on Numerical Simulation

Liquid Natural Gas (LNG) is a kind of quality and valuable industrial chemical, produced by compressing and cooling natural gas to -162 degree Celsius. The safety issues are worth concern, especially in the LNG storage and transportation processes (e.g. the ultra-low temperature may be threatening once leakage happens.) This article chooses the ISO 40-foot containers as demonstration for the flexible transportation way, which supports waterway, road, railway as well as multimodal transport. Due to the fact that relevant historical data is rare, a numerical simulation method used to simulate the LNG leakage accident, especially the consequence analysis of LNG leakage from tank containers. In order to increase the reliability of research, this article supposes two cases to do comparative analysis. The research findings would be helpful for the emergency planning and response of LNG accident.