Establishment of a novel predictive reliability assessment strategy for ship machinery

There is no doubt that recent years, maritime industry is moving forward to novel and sophisticated inspection and maintenance practices. Nowadays maintenance is encountered as an operational method, which can be employed both as a profit generating process and a cost reduction budget centre through an enhanced Operation and Maintenance (O&M) strategy. In the first place, a flexible framework to be applicable on complex system level of machinery can be introduced towards ship maintenance scheduling of systems, subsystems and components.;This holistic inspection and maintenance notion should be implemented by integrating different strategies, methodologies, technologies and tools, suitably selected by fulfilling the requirements of the selected ship systems. In this thesis, an innovative maintenance strategy for ship machinery is proposed, namely the Probabilistic Machinery Reliability Assessment (PMRA) strategy focusing towards the reliability and safety enhancement of main systems, subsystems and maintainable units and components.;In this respect, the combination of a data mining method (k-means), the manufacturer safety aspects, the dynamic state modelling (Markov Chains), the probabilistic predictive reliability assessment (Bayesian Belief Networks) and the qualitative decision making (Failure Modes and Effects Analysis) is employed encompassing the benefits of qualitative and quantitative reliability assessment. PMRA has been clearly demonstrated in two case studies applied on offshore platform oil and gas and selected ship machinery.;The results are used to identify the most unreliability systems, subsystems and components, while advising suitable practical inspection and maintenance activities. The proposed PMRA strategy is also tested in a flexible sensitivity analysis scheme.There is no doubt that recent years, maritime industry is moving forward to novel and sophisticated inspection and maintenance practices. Nowadays maintenance is encountered as an operational method, which can be employed both as a profit generating process and a cost reduction budget centre through an enhanced Operation and Maintenance (O&M) strategy. In the first place, a flexible framework to be applicable on complex system level of machinery can be introduced towards ship maintenance scheduling of systems, subsystems and components.;This holistic inspection and maintenance notion should be implemented by integrating different strategies, methodologies, technologies and tools, suitably selected by fulfilling the requirements of the selected ship systems. In this thesis, an innovative maintenance strategy for ship machinery is proposed, namely the Probabilistic Machinery Reliability Assessment (PMRA) strategy focusing towards the reliability and safety enhancement of main systems, subsystems and maintainable units and components.;In this respect, the combination of a data mining method (k-means), the manufacturer safety aspects, the dynamic state modelling (Markov Chains), the probabilistic predictive reliability assessment (Bayesian Belief Networks) and the qualitative decision making (Failure Modes and Effects Analysis) is employed encompassing the benefits of qualitative and quantitative reliability assessment. PMRA has been clearly demonstrated in two case studies applied on offshore platform oil and gas and selected ship machinery.;The results are used to identify the most unreliability systems, subsystems and components, while advising suitable practical inspection and maintenance activities. The proposed PMRA strategy is also tested in a flexible sensitivity analysis scheme

An investigation into the development of an advanced ship performance monitoring and analysis system

PhD ThesisThe complete ban on TBT in marine antifouling coatings in 2008, rocketing fuel prices over the past six years, environmental concern and upcoming energy efficiency indices for ships have resulted in a strong interest of the shipping industry to monitor, evaluate and optimise ship performance. Furthermore, the complete ban on TBT in anti-fouling coatings resulted in new types of foul-release hull-coatings, based con silicon, whose effectiveness and performance still needs to be evaluated. Because of the difficulty of measuring coating roughness in service and the large effect of marine bio-fouling on ship performance, a research project was setup at Newcastle University in collaboration with a major paint company to investigate the ways to evaluate hull coating through ship performance monitoring. This thesis describes the details of this project which aimed to investigate the feasibility of a real-time ship performance monitoring and analysis (PM&A) system by implementation and evaluation onboard a 16m research vessel and 300.000dwt VLCC. The thesis starts with a review of the state of art of PM&A systems. The main weaknesses of existing PM&A systems is that often abstract logbook data is used as input and that too little attention is paid to data quality. Furthermore, the systems often act as a black box, showing little insight in data analysis, harming the reliability and trustworthiness of output indicators. Additionally, there are large differences in the way that performance data is corrected to standard conditions, resulting in contradicting and unreliable performance indicators. The thesis focuses therefore on theoretically sound, transparent data analysis and improved data collection. In the thesis, all performance affecting environmental and operational conditions have been reviewed including sensor characteristics and data acquisition aspects. Based on the experience from the analysis of the data collected from both vessels, it reveals that automatic, real-time data collection and rational filtering for periods of acceleration, deceleration, course deviation, drift, shallow water and ship motion is the way forward for accurate performance monitoring. Performance analysis is highly sensitive to errors in shaft torque and ship speed through water. A frequently calibrated/validated shaft torque & RPM sensor and Doppler speed log are therefore the most important sensors for performance monitoring. Speed logs are T.W.F. Hasselaar PhD thesis, 2010 ii affected by many environmental conditions and cannot be used directly for performance monitoring. Other ways to determine ship speed through water, e.g. using the propeller inflow speed, are however affected by hull fouling and loading deviations unless corrected for accordingly. Corrections using full scale trials are then necessary to avoid overestimation of the effects of hull fouling on ship performance. To avoid these errors, a method is described to use the speed log by evaluating its reliability and utilise its reading for performance analysis only in periods where it can be considered reliable. A new transparent analysis method is described to analyse ship performance based on conversion of torque and rpm at constant ship speed. The method differentiates between the hull and propeller performance by empirically correcting the propeller open water diagram for roughness (periodically measured by divers). Evaluation of the proposed PM&A system on both vessels indicates that reliable performance indicatgors can be calculated but that fluctuations in performance indicators of ±12% remain unavoidable due to inaccurate wave observations and errors from the speed log. Trials on the research vessel furthermore show that the system is able to identify fouling, but sensor accuracy requires further research so that fouling can be defined with less performance data and higher reliability. This thesis demonstrates for the first time in open literature that the design and implementation of a transparent and fully automatic, real-time, shipboard PM&A system is perfectly viable and can be installed on any ship with the use of reliable sensors.International Pain

Environmental impact of passenger ships in port

The environmental impact of ships can be of different types. This thesis covers air pollution due to chemicals and concentrates on local effects due to compounds emitted in the exhaust gases of internal combustion engines and acoustic pollution. The attention has been focused on the consequences of the presence of many ships in ports located close to inhabited zones. For port-scale analyzes, the case study is the port of Naples for which traffics, geographic conformation, meteorological conditions, results of experimental campaigns both in the field of acoustic and environmental impact are available. In the field of polluting emissions, the case study for the simulations is a catamaran in service at the port of Naples for which experimental measurements at sea and bench tests are available. For the simulation of acoustic emissions, the case study is a passenger ship for which experimental measurements and forecast data are available. Experimental campaigns and simulations have been carried out on the port of Naples and most of the applications concern passenger ships, but methods and procedures can be applied to a general case. The thesis consists of six chapters, briefly introduced here. Each chapter contains a first subsection named "aims and scope" precisely to describe its main purposes in a more extended way than the summary presented here. The theme is first framed in the more general context of the environmental impact of anthropogenic activities and of marine transportation in particular assessment studies and documents issued by international bodies reporting targets for limiting the global environmental impact of the shipping sector are briefly summarized. Recalls on the main mechanisms of formation and reduction of pollutants are exposed. The second chapter describes the bottom-up method aimed at estimating the emissions of passenger ships in port. To obtain an estimation of all the emissions a series of very specific steps are necessary. The main information to be collected and produced concerns: traffic, routes, arrival and departure schedules, engine loads, emissions, heights, and diameters of the funnels. The technique of data collection and its use was gradually deepened (from simple cruise calendar to AIS data). The main application on the entire port sees the use of AIS data. The starting AIS data have been processed through an "ad hoc" MATLAB code capable of managing a relevant amount of data and returning a complete calendar of all the movements of every ship arriving and operating in the port. The use of AIS data has brought about improvements in the calculation methodology for emissions as well, allowing for example a more accurate analysis of average speeds in port and idle times. The port of Naples, where all the analysis were developed, is presented next. The traffics for the years and reference periods chosen in the subsequent analyzes are presented (2012, 2016, and 2018). A comprehensive study of the environmental impact of ships cannot be separated from the creation of atmospheric dispersion models. These models require the flow of pollutants emitted in the main operational phases in port (navigation, maneuvering, and mooring) as the main inputs. The results allow to estimate the weight that the passenger branch has on air quality also thanks to cross-comparisons with port measurements and ARPAC (Regional Agency for Environmental Protection in Campania) data. After the analysis of the environmen0tal impact on a port scale, the problem of emissions has been approached by applying a designated simulation, with the aim to overcome the use of emission factors. The first part of the chapter describes a state of the art of simulation model and an in-depth analysis of the main emission simulation methodologies. An engine model has been created in RICARDO WAVE environment; this engine model was validated and calibrated on an engine installed onboard a passenger ship operating in the port of Naples. Bench test results in terms of power, torque, consumption, and rpm have been used to calibrate the model while experimental measurements validated it. In the dissertation, a description of the case study (ship, engine, bench tests, and sea trials), a description of the model, and an interpretation of the results are presented. The validation on sea trials shows the effectiveness of the model both in terms of main engine parameters and emissions. At the end of the chapter, a comparison between the three emission estimation methodologies (EMEP-EEA, with AIS data, simulations, and experimental campaign) has been carried out. The next chapter of the thesis concerns the assessment of the acoustic impact of passenger ships in port. The structure of the research is typically the same: simulation and experimental results. The first part shows some experimental surveys made on a passenger ship in port that served as validation of a simulation model built in the TERRAIN OLIVE TREE LAB SUITE environment. The second and last part presents the methodology and results obtained in the context of a collaborative research project between the Universities of Naples, Genoa, and Trieste. The project aimed at characterizing the acoustic impact of a ship in light of the new additional class notation published by the Lloyds Register "Procedure for the Determination of Airborne Noise Emissions from Marine Vessels Airborne Noise Emissions from Marine Vessels". The last chapter sets out three applications in order to keep the problem set in a global scale context. The first presents an analysis of the possible countermeasures that can be applied to the cruise ship fleet aimed at environmental safeguarding (DNV Appraisal Tool), in the wake of the EEOI and EEDI. Furthermore, in the context of the environmental impact on a port scale, preliminary measurements of polluting emissions using remote measurement instruments (LIDAR) were carried out with the aim of allowing an indirect estimate of the concentrations of pollutants in the exhausts of ships, thus significantly reducing the uncertainties related to ground-level measurements with active or passive samplers. The last application, on the other hand, concerns the ports and the possible activities and initiatives to be implemented in order to host fleet of increasingly green and eco-sustainable ships (Environmental Ship Index)

Aeronautical Engineering: A special bibliography with indexes, supplement 39

This special bibliography lists 417 reports, articles, and other documents introduced into the NASA scientific and technical information system in December 1973

Powering performance of a self-propelled ship in waves

The ability to accurately predict the powering performance of a ship when travelling in waves is of high importance for the design of new ships. Almost a century of experience exists regarding how to predict the mean resistance increase in waves compared to calm water. Despite this, improvements in numerical models are still in high demand. Traditionally, the mean increase together with the calm water resistance and propeller open water curves are used to determine the powering performance. This thesis argues that, to achieve better predictions, a more holistic approach can be taken. A RANS based numerical approach to predicting the performance of a self propelled ship in waves is presented. The model is supported by a review of previous literature as well as new experiments to determine what phenomena need to be modelled. It is concluded that the surge force amplitude in waves is something that is not well studied but that has an impact on the propeller performance. The experiments show that this is likely to be harder to predict than the mean increase. Furthermore, the inclusion of RPM control in the model is seen as important to make it better suited for predicting the performance. In developing the numerical model, it is shown that the amplitude and phase of the viscous surge force are affected to some extent by the way the RANS equations are solved numerically. Recommendations on the choice of schemes are given based on several comparative studies where a limited TVD scheme is found to give the best representation of the flow. Furthermore, detailed analysis on how the boundary layer is affected by the passing waves is presented. A framework for coupling the RANS solver with a simplified propeller model is presented. This is a powerful tool that allows for a broad range of present and future studies regarding propeller modelling and RPM control for self propelled simulations in waves. The implementation of Blade Element Momentum theory in the framework is outlined and a correction able to achieve a satisfactory run time coupling in terms of identifying the propeller induced velocities from the total wake is presented. The coupled solver is found to be a computationally efficient tool for studying ship performance in waves. It is applied to study the propulsive performance of the KCS in unsteady inflow conditions. Reasonable agreement with experiments is found both for resistance and for propeller performance. Overall, the findings and methods presented here represent a contribution towards better predictions of the performance of self propelled ships in waves

Aeronautical Engineering: A continuing bibliography with indexes, supplement 99

This bibliography lists 292 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1978

New Indicators for the Assessment and Prevention of Noise Nuisance

This Special Issue was launched to promote a subject that is deserving of more attention: the study of new metrics, indicators or evaluation methods for noise exposure, and the relationship of noise with annoyance or other health effects, thus not relying only on an average noise exposure measure. This Special Issue on the theme of the New Indicators for the Assessment and Prevention of Noise Nuisance has attracted the interest of authors from all over the world, with the publication of two reviews and two communications, as well as original research papers. Progress has been made in the investigated topic; however, it is still necessary to increase the awareness of the population, both in geographical terms and for workers in specific sectors, such as the marine industry. It emerged that it is essential to carry out future studies that distinguish better between different sound sources with respect to their sound quality in terms of frequency, time pattern (fluctuation, emergence), and psychoacoustic indices, because a differential human reaction to sound sources is increasingly evident. More longitudinal studies are required. However, cross-sectional studies employing a more detailed soundscape description (including background) by competing sound indices are also useful to further the required knowledge to understand the human response in terms of the broad spectrum of potential adverse effects on health and quality of life

Advanced Sensors for Real-Time Monitoring Applications

It is impossible to imagine the modern world without sensors, or without real-time information about almost everything—from local temperature to material composition and health parameters. We sense, measure, and process data and act accordingly all the time. In fact, real-time monitoring and information is key to a successful business, an assistant in life-saving decisions that healthcare professionals make, and a tool in research that could revolutionize the future. To ensure that sensors address the rapidly developing needs of various areas of our lives and activities, scientists, researchers, manufacturers, and end-users have established an efficient dialogue so that the newest technological achievements in all aspects of real-time sensing can be implemented for the benefit of the wider community. This book documents some of the results of such a dialogue and reports on advances in sensors and sensor systems for existing and emerging real-time monitoring applications