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Scientific Seminar in memory of Professor Stefan Perycz

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Dettagli della rivista
Formato
Rivista
eISSN
2083-7429
Pubblicato per la prima volta
20 Jul 2007
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

Volume 22 (2015): Edizione 3 (September 2015)

Dettagli della rivista
Formato
Rivista
eISSN
2083-7429
Pubblicato per la prima volta
20 Jul 2007
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

13 Articoli
Accesso libero

M-Estimation as a Tool Supporting a Vessel Traffic Controller in the VTS System

Pubblicato online: 15 Oct 2015
Pagine: 3 - 13

Astratto

Abstract

In order to improve maritime safety and the efficiency of vessel traffic, systems supervising vessel traffic, i.e. VTS (Vessel Traffic Service), started to be created. These systems are aimed to control vessel traffic in waters where traffic congestion, a large concentration of vessels or the presence of navigational hazards creates a risk of collision or stranding.

VTS systems constitute maritime safety centres and they must be equipped with appropriate devices in order to be fully functional. Among devices that provide information about vessels are coastal radar stations which are located around a monitored sea area. This kind of spatial arrangement of these stations can be used to simultaneously obtain information about every vessel, but such observations may be fraught with serious errors. Therefore, the estimation methods that are employed and developed in geodesy can be used to improve the accuracy with which a vessel’s position is determined. The Interactive Navigational Structure, i.e. IANS, is an example of how these methods can be applied in navigation; this term has already been introduced into the literature (Czaplewski, 2004). The text below presents the theoretical assumptions underlying the use of IANS as a tool supporting a vessel traffic controller using the VTS system in his/her work. This presentation is supported by a numerical test that was performed in the waters of the Bay of Gdańsk which are covered by the VTS system.

Keywords

  • navigation
  • radar navigation
  • Vessel Traffic Services
  • M-estimation
  • Interactive Navigational Structures
Accesso libero

Methods for Optimization of Sea Waterway Systems and their Application

Pubblicato online: 15 Oct 2015
Pagine: 14 - 19

Astratto

Abstract

This paper presents developed optimization methods for sea waterway systems. Objective function of optimization of sea waterway systems have been formulated and its detail form for fairways has been determined. Three probabilistic methods for determining safe bed-breadth of fairway are described. Limitations of the presented methods are also discussed. The developed optimization methods for sea waterway systems have been applied to determine parameters of a modernized fairway between Świnoujście and Szczecin as well as its navigation systems

Parole chiave

  • Optimization of sea waterway systems
  • sea traffic engineering
  • probabilistic methods of determination safe breadth of fairways.
Accesso libero

Celestial Navigation Fix Based on Particle Swarm Optimization

Pubblicato online: 15 Oct 2015
Pagine: 20 - 27

Astratto

Abstract

A technique for solving celestial fix problems is proposed in this study. This method is based on Particle Swarm Optimization from the field of swarm intelligence, utilizing its superior optimization and searching abilities to obtain the most probable astronomical vessel position. In addition to being applicable to two-body fix, multi-body fix, and high-altitude observation problems, it is also less reliant on the initial dead reckoning position. Moreover, by introducing spatial data processing and display functions in a Geographical Information System, calculation results and chart work used in Circle of Position graphical positioning can both be integrated. As a result, in addition to avoiding tedious and complicated computational and graphical procedures, this work has more flexibility and is more robust when compared to other analytical approaches.

Parole chiave

  • Particle Swarm Optimization
  • Celestial navigation
  • Intercept method
Accesso libero

Numerical and Analytical Approaches for Roll Motion Analysis in Regular Longitudinal Waves

Pubblicato online: 15 Oct 2015
Pagine: 28 - 35

Astratto

Abstract

In this study numerical and analytical approaches were investigated in terms of accuracy of their results, practicality of solution and ability to reproduce the main features of the parametric roll phenomenon such as loss of stability and bifurcations in parametric roll motion analysis of ships. In general, single-degree-of-freedom analytical approach is based on reducing number of degrees of freedom from 3 to 1 by using the quasi-static Froude-Krylov assumption, incorporating heave and pitch effects by means of a time varying restoring moment. On the other hand, numerical approaches to motion of six and four degrees of freedom are based on three dimensional diffraction/radiation and potential flow theories. In summary, this paper reveals that analytical approaches are sufficiently adequate to obtain accurate practical results for this relatively complex phenomenon.

Parole chiave

  • Parametric roll motion
  • bifurcations
  • panel method
  • AQWA
Accesso libero

Use of Satellite Data in Monitoring of Hydrophysical Parameters of the Baltic Sea Environment

Pubblicato online: 15 Oct 2015
Pagine: 36 - 42

Astratto

Abstract

Intensive development of infrastructure for fast processing of outsized amount of space-borne data enables now to use the satellite data for operational controlling the state of its environment. In our presentation we show some examples of analysis of processes in marine environment which are possible due to satellite data and algorithms of its processing developed in SatBaltic Project. It concerns supporting of modelling of solar energy inflow to the sea with space-borne input data, identification and analysis of sea ice cover, supporting of oil spill detection, and identification of phenomena which modify spatial distribution of the sea surface temperature.

Parole chiave

  • satellite remote sensing
  • Baltic
  • SST
  • solar energy
  • sea ice
  • oil spill
Accesso libero

Practical Applicability and Preliminary Results of the Baltic Environmental Satellite Remote Sensing System (Satbałtyk)

Pubblicato online: 15 Oct 2015
Pagine: 43 - 49

Astratto

Abstract

The SatBałtyk (Satellite Monitoring of the Baltic Sea Environment) project is being realized in Poland by the SatBałtyk Scientific Consortium, specifically appointed for this purpose, which associates four scientific institutions: the Institute of Oceanology PAN in Sopot - coordinator of the project, the University of Gdańsk (Institute of Oceanography), the Pomeranian Academy in Słupsk (Institute of Physics) and the University of Szczecin (Institute of Marine Sciences). The project is aiming to prepare a technical infrastructure and set in motion operational procedures for the satellite monitoring of the Baltic Sea ecosystem. The main sources of input data for this system will be the results of systematic observations by metrological and environmental satellites such as TIROS N/NOAA, MSG (currently Meteosat 10), EOS/AQUA and Sentinel -1, 2, 3 (in the future). The system will deliver on a routine basis the variety of structural and functional properties of this sea, based on data provided by relevant satellites and supported by hydro-biological models. Among them: the solar radiation influx to the sea’s waters in various spectral intervals, energy balances of the short- and long-wave radiation at the Baltic Sea surface and in the upper layers of the atmosphere over the Baltic, sea surface temperature distribution, dynamic states of the water surface, concentrations of chlorophyll a and other phytoplankton pigments in the Baltic waters, spatial distributions of algal blooms, the occurrence of coastal upwelling events, and the characteristics of primary production of organic matter and photosynthetically released oxygen in the water and many others. The structure of the system and preliminary results will be presented.

Keywords

  • bearing capacity factor
  • displacement
  • compression
  • tension
  • depth factor
Accesso libero

Daily Radiation Budget of the Baltic Sea Surface from Satellite Data

Pubblicato online: 15 Oct 2015
Pagine: 50 - 56

Astratto

Abstract

Recently developed system for assessment of radiation budget for the Baltic Sea has been presented and verified. The system utilizes data from various sources: satellite, model and in situ measurements. It has been developed within the SatBałtyk project (Satellite Monitoring of the Baltic Sea Environment - www.satbaltyk.eu) where the energy radiation budget is one of the key element. The SatBałtyk system generates daily maps of the all components of radiation budget on every day basis. We show the scheme of making daily maps, applied algorithms and empirical data collection within the system. An empirical verification of the system has been carried out based on empirical data collected on the oil rig placed on the Baltic Sea. This verification concerned all the components of the surface radiation budget. The average daily NET products are estimated with statistical error ca. 13 Wm-2. The biggest absolute statistical error is for LWd component and equals 14 Wm-2. The relative error in relation to the average annual values for whole Baltic is the biggest for SWu and reaches 25%. All estimated components have correlation coefficient above 0.91.

Parole chiave

  • Surface radiation budget
  • satellite
  • Baltic Sea
Accesso libero

Influence of Pitting Corrosion on Fatigue and Corrosion Fatigue of Ship and Offshore Structures, Part II: Load - Pit - Crack Interaction

Pubblicato online: 15 Oct 2015
Pagine: 57 - 66

Astratto

Abstract

In the paper has been discussed influence of stresses on general corrosion rate and corrosion pit nucleation rate and growth , whose presence has been questioned by some authors but accepted by most of them. Influence of roughness of pit walls on fatigue life of a plate suffering pit corrosion and presence of the so called „ non-damaging” pits which never lead to initiation of fatigue crack, has been presented. Possibility of prediction of pit-to-crack transition moment by two different ways, i.e. considering a pit a stress concentrator or an equivalent crack, has been analyzed. Also, influence of statistical distribution of depth of corrosion pits as well as anticorrosion protection on fatigue and corrosion fatigue has been described.

Parole chiave

  • Pitting corrosion
  • fatigue
  • ship structures
  • offshore structures.
Accesso libero

Comparing Guidelines Concerning Construction of the S-N Curve within Limited Fatigue Life Range

Pubblicato online: 15 Oct 2015
Pagine: 67 - 74

Astratto

Abstract

The article collates guidelines concerning experimental construction of the S-N fatigue curves within a limited fatigue life range. An attempt is made to compare these guidelines, based on experimental data recorded during rotating bending of a notched specimen made of 42CrMo4. The recorded differences in fatigue life values between the constructed curves reach the maximum of 12.2%. According to the above guidelines, the number of tests in particular test series varies from 6 to 28. Based on the performed analysis a conclusion was made that the increase in the number of tests leads to the increase of accuracy but, on the other hand, remarkably increases the time of the experiment and, consequently, its cost. In this context, it is the research worker who, taking into account a possible future use of the fatigue curve, should individually decide about its accuracy.

Parole chiave

  • high-cycle fatigue
  • S-N curve
  • fatigue tests
Accesso libero

Laser Doppler Vibrometer Based Examination of the Efficiency of Introducing Artificial Delaminations into Composite Shells

Pubblicato online: 15 Oct 2015
Pagine: 75 - 81

Astratto

Abstract

During its operation, the laminate shell of the watercraft hull can be exposed to local stability losses caused by the appearance and development of delaminations. The sources of these delaminations are discontinuities, created both in the production process and as a result of bumps of foreign bodies into the hull in operation. In the environment of fatigue loads acting on the hull, the delaminations propagate and lead to the loss of load capacity of the hull structure. There is a need to improve diagnostic systems used in Structural Health Monitoring (SHM) of laminate hull elements to detect and monitor the development of the delaminations. Effective diagnostic systems used for delamination assessment base on expert systems. Along with other tools, the expert diagnostic advisory systems make use of the non-destructive examination method which consists in generating elastic waves in the hull shell structure and observing their changes by comparing the recorded signal with damage patterns collected in the expert system database. This system requires introducing certain patterns to its knowledge base, based on the results of experimental examinations performed on specimens with implemented artificial delaminations. The article presents the results of the examination oriented on assessing the delaminations artificially generated in the structure of glass- and carbon-epoxy laminates by introducing local non-adhesive layers with the aid of thin polyethylene film, teflon insert, or thin layer of polyvinyl alcohol. The efficiency of each method was assessed using laser vibrometry. The effect of the depth of delamination position in the laminate on the efficiency of the applied method is documented as well.

Parole chiave

  • watercraft hull
  • laminate
  • artificial delamination
  • SHM diagnostics
  • advisory expert system knowledge base
Accesso libero

Study of Harmonic Detection Methods under Non-Ideal Conditions in Ship Power Network

Pubblicato online: 15 Oct 2015
Pagine: 82 - 89

Astratto

Abstract

An improved harmonic detection method based on average arithmetic is proposed. According to the research results, the designed solution uses an LPF (low-pass-filter) and a mean value module connected in series instead of the conventional mean value module, and simultaneously, a three-phase voltage phase-locked module instead of commonly used PLL (phase lock loop) module is applied in order to reduce the influence caused by three-phase distorted voltage and rapid variation of load. The experimental results show that the application of this solution leads to increase in the accuracy of harmonics detection for distorted three-phase voltage and rapid variation of load.

Parole chiave

  • distorted three-phase voltage
  • rapid-variation load
  • harmonic detection
  • average arithmetic
Accesso libero

An Experimental Study of Emission and Combustion Characteristics of Marine Diesel Engine in Case of Cylinder Valves Leakage

Pubblicato online: 15 Oct 2015
Pagine: 90 - 98

Astratto

Abstract

Presented paper shows the results of the laboratory tests on the relationship between throttling of both air intake duct and exhaust gas duct and a gaseous emission from the marine engine. The object of research is a laboratory, four-stroke, DI diesel engine, operated at loads from 50 kW to 250 kW at a constant speed equal to 750 rpm. During the laboratory tests over 50 parameters of the engine were measured with its technical condition recognized as a „working properly” and with simulated leakage of both air intake valve and exhaust gas valve on the second cylinder. The results of this laboratory research confirm that the leakage of cylinder valves causes no significant changes of the thermodynamic parameters of the engine. Simulated leakages through the inlet and exhaust valve caused a significant increase in fuel consumption of the engine. Valve leakages cause an increase of the exhaust gas temperature behind the cylinder with leakage and behind other cylinders. The exhaust gas temperature increase is relatively small and clearly visible only at low loads of the engine. The increase of the temperature and pressure of the charging air behind the intercooler were observed too. Charging air temperature is significantly higher during the engine operation with inlet valve leakage. The study results show significant increases of the CO, NOx and CO2 emission for all the mentioned malfunctions. The conclusion is that the results of measurements of the composition of the exhaust gas may contain valuable diagnostic information about the technical condition of the air intake duct and the exhaust gas duct of the marine engine.

Parole chiave

  • marine diesel engine
  • exhaust gas composition
  • emission
  • exhaust gas valve leakage
  • inlet valve leakage
Accesso libero

Tryton Supercomputer Capabilities for Analysis of Massive Data Streams

Pubblicato online: 15 Oct 2015
Pagine: 99 - 104

Astratto

Abstract

The recently deployed supercomputer Tryton, located in the Academic Computer Center of Gdansk University of Technology, provides great means for massive parallel processing. Moreover, the status of the Center as one of the main network nodes in the PIONIER network enables the fast and reliable transfer of data produced by miscellaneous devices scattered in the area of the whole country. The typical examples of such data are streams containing radio-telescope and satellite observations. Their analysis, especially with real-time constraints, can be challenging and requires the usage of dedicated software components. We propose a solution for such parallel analysis using the supercomputer, supervised by the KASKADA platform, which with the conjunction with immerse 3D visualization techniques can be used to solve problems such as pulsar detection and chronometric or oil-spill simulation on the sea surface.

Parole chiave

  • supercomputer
  • data streams
  • distributed systems
  • radio-telescope
  • satellite
13 Articoli
Accesso libero

M-Estimation as a Tool Supporting a Vessel Traffic Controller in the VTS System

Pubblicato online: 15 Oct 2015
Pagine: 3 - 13

Astratto

Abstract

In order to improve maritime safety and the efficiency of vessel traffic, systems supervising vessel traffic, i.e. VTS (Vessel Traffic Service), started to be created. These systems are aimed to control vessel traffic in waters where traffic congestion, a large concentration of vessels or the presence of navigational hazards creates a risk of collision or stranding.

VTS systems constitute maritime safety centres and they must be equipped with appropriate devices in order to be fully functional. Among devices that provide information about vessels are coastal radar stations which are located around a monitored sea area. This kind of spatial arrangement of these stations can be used to simultaneously obtain information about every vessel, but such observations may be fraught with serious errors. Therefore, the estimation methods that are employed and developed in geodesy can be used to improve the accuracy with which a vessel’s position is determined. The Interactive Navigational Structure, i.e. IANS, is an example of how these methods can be applied in navigation; this term has already been introduced into the literature (Czaplewski, 2004). The text below presents the theoretical assumptions underlying the use of IANS as a tool supporting a vessel traffic controller using the VTS system in his/her work. This presentation is supported by a numerical test that was performed in the waters of the Bay of Gdańsk which are covered by the VTS system.

Keywords

  • navigation
  • radar navigation
  • Vessel Traffic Services
  • M-estimation
  • Interactive Navigational Structures
Accesso libero

Methods for Optimization of Sea Waterway Systems and their Application

Pubblicato online: 15 Oct 2015
Pagine: 14 - 19

Astratto

Abstract

This paper presents developed optimization methods for sea waterway systems. Objective function of optimization of sea waterway systems have been formulated and its detail form for fairways has been determined. Three probabilistic methods for determining safe bed-breadth of fairway are described. Limitations of the presented methods are also discussed. The developed optimization methods for sea waterway systems have been applied to determine parameters of a modernized fairway between Świnoujście and Szczecin as well as its navigation systems

Parole chiave

  • Optimization of sea waterway systems
  • sea traffic engineering
  • probabilistic methods of determination safe breadth of fairways.
Accesso libero

Celestial Navigation Fix Based on Particle Swarm Optimization

Pubblicato online: 15 Oct 2015
Pagine: 20 - 27

Astratto

Abstract

A technique for solving celestial fix problems is proposed in this study. This method is based on Particle Swarm Optimization from the field of swarm intelligence, utilizing its superior optimization and searching abilities to obtain the most probable astronomical vessel position. In addition to being applicable to two-body fix, multi-body fix, and high-altitude observation problems, it is also less reliant on the initial dead reckoning position. Moreover, by introducing spatial data processing and display functions in a Geographical Information System, calculation results and chart work used in Circle of Position graphical positioning can both be integrated. As a result, in addition to avoiding tedious and complicated computational and graphical procedures, this work has more flexibility and is more robust when compared to other analytical approaches.

Parole chiave

  • Particle Swarm Optimization
  • Celestial navigation
  • Intercept method
Accesso libero

Numerical and Analytical Approaches for Roll Motion Analysis in Regular Longitudinal Waves

Pubblicato online: 15 Oct 2015
Pagine: 28 - 35

Astratto

Abstract

In this study numerical and analytical approaches were investigated in terms of accuracy of their results, practicality of solution and ability to reproduce the main features of the parametric roll phenomenon such as loss of stability and bifurcations in parametric roll motion analysis of ships. In general, single-degree-of-freedom analytical approach is based on reducing number of degrees of freedom from 3 to 1 by using the quasi-static Froude-Krylov assumption, incorporating heave and pitch effects by means of a time varying restoring moment. On the other hand, numerical approaches to motion of six and four degrees of freedom are based on three dimensional diffraction/radiation and potential flow theories. In summary, this paper reveals that analytical approaches are sufficiently adequate to obtain accurate practical results for this relatively complex phenomenon.

Parole chiave

  • Parametric roll motion
  • bifurcations
  • panel method
  • AQWA
Accesso libero

Use of Satellite Data in Monitoring of Hydrophysical Parameters of the Baltic Sea Environment

Pubblicato online: 15 Oct 2015
Pagine: 36 - 42

Astratto

Abstract

Intensive development of infrastructure for fast processing of outsized amount of space-borne data enables now to use the satellite data for operational controlling the state of its environment. In our presentation we show some examples of analysis of processes in marine environment which are possible due to satellite data and algorithms of its processing developed in SatBaltic Project. It concerns supporting of modelling of solar energy inflow to the sea with space-borne input data, identification and analysis of sea ice cover, supporting of oil spill detection, and identification of phenomena which modify spatial distribution of the sea surface temperature.

Parole chiave

  • satellite remote sensing
  • Baltic
  • SST
  • solar energy
  • sea ice
  • oil spill
Accesso libero

Practical Applicability and Preliminary Results of the Baltic Environmental Satellite Remote Sensing System (Satbałtyk)

Pubblicato online: 15 Oct 2015
Pagine: 43 - 49

Astratto

Abstract

The SatBałtyk (Satellite Monitoring of the Baltic Sea Environment) project is being realized in Poland by the SatBałtyk Scientific Consortium, specifically appointed for this purpose, which associates four scientific institutions: the Institute of Oceanology PAN in Sopot - coordinator of the project, the University of Gdańsk (Institute of Oceanography), the Pomeranian Academy in Słupsk (Institute of Physics) and the University of Szczecin (Institute of Marine Sciences). The project is aiming to prepare a technical infrastructure and set in motion operational procedures for the satellite monitoring of the Baltic Sea ecosystem. The main sources of input data for this system will be the results of systematic observations by metrological and environmental satellites such as TIROS N/NOAA, MSG (currently Meteosat 10), EOS/AQUA and Sentinel -1, 2, 3 (in the future). The system will deliver on a routine basis the variety of structural and functional properties of this sea, based on data provided by relevant satellites and supported by hydro-biological models. Among them: the solar radiation influx to the sea’s waters in various spectral intervals, energy balances of the short- and long-wave radiation at the Baltic Sea surface and in the upper layers of the atmosphere over the Baltic, sea surface temperature distribution, dynamic states of the water surface, concentrations of chlorophyll a and other phytoplankton pigments in the Baltic waters, spatial distributions of algal blooms, the occurrence of coastal upwelling events, and the characteristics of primary production of organic matter and photosynthetically released oxygen in the water and many others. The structure of the system and preliminary results will be presented.

Keywords

  • bearing capacity factor
  • displacement
  • compression
  • tension
  • depth factor
Accesso libero

Daily Radiation Budget of the Baltic Sea Surface from Satellite Data

Pubblicato online: 15 Oct 2015
Pagine: 50 - 56

Astratto

Abstract

Recently developed system for assessment of radiation budget for the Baltic Sea has been presented and verified. The system utilizes data from various sources: satellite, model and in situ measurements. It has been developed within the SatBałtyk project (Satellite Monitoring of the Baltic Sea Environment - www.satbaltyk.eu) where the energy radiation budget is one of the key element. The SatBałtyk system generates daily maps of the all components of radiation budget on every day basis. We show the scheme of making daily maps, applied algorithms and empirical data collection within the system. An empirical verification of the system has been carried out based on empirical data collected on the oil rig placed on the Baltic Sea. This verification concerned all the components of the surface radiation budget. The average daily NET products are estimated with statistical error ca. 13 Wm-2. The biggest absolute statistical error is for LWd component and equals 14 Wm-2. The relative error in relation to the average annual values for whole Baltic is the biggest for SWu and reaches 25%. All estimated components have correlation coefficient above 0.91.

Parole chiave

  • Surface radiation budget
  • satellite
  • Baltic Sea
Accesso libero

Influence of Pitting Corrosion on Fatigue and Corrosion Fatigue of Ship and Offshore Structures, Part II: Load - Pit - Crack Interaction

Pubblicato online: 15 Oct 2015
Pagine: 57 - 66

Astratto

Abstract

In the paper has been discussed influence of stresses on general corrosion rate and corrosion pit nucleation rate and growth , whose presence has been questioned by some authors but accepted by most of them. Influence of roughness of pit walls on fatigue life of a plate suffering pit corrosion and presence of the so called „ non-damaging” pits which never lead to initiation of fatigue crack, has been presented. Possibility of prediction of pit-to-crack transition moment by two different ways, i.e. considering a pit a stress concentrator or an equivalent crack, has been analyzed. Also, influence of statistical distribution of depth of corrosion pits as well as anticorrosion protection on fatigue and corrosion fatigue has been described.

Parole chiave

  • Pitting corrosion
  • fatigue
  • ship structures
  • offshore structures.
Accesso libero

Comparing Guidelines Concerning Construction of the S-N Curve within Limited Fatigue Life Range

Pubblicato online: 15 Oct 2015
Pagine: 67 - 74

Astratto

Abstract

The article collates guidelines concerning experimental construction of the S-N fatigue curves within a limited fatigue life range. An attempt is made to compare these guidelines, based on experimental data recorded during rotating bending of a notched specimen made of 42CrMo4. The recorded differences in fatigue life values between the constructed curves reach the maximum of 12.2%. According to the above guidelines, the number of tests in particular test series varies from 6 to 28. Based on the performed analysis a conclusion was made that the increase in the number of tests leads to the increase of accuracy but, on the other hand, remarkably increases the time of the experiment and, consequently, its cost. In this context, it is the research worker who, taking into account a possible future use of the fatigue curve, should individually decide about its accuracy.

Parole chiave

  • high-cycle fatigue
  • S-N curve
  • fatigue tests
Accesso libero

Laser Doppler Vibrometer Based Examination of the Efficiency of Introducing Artificial Delaminations into Composite Shells

Pubblicato online: 15 Oct 2015
Pagine: 75 - 81

Astratto

Abstract

During its operation, the laminate shell of the watercraft hull can be exposed to local stability losses caused by the appearance and development of delaminations. The sources of these delaminations are discontinuities, created both in the production process and as a result of bumps of foreign bodies into the hull in operation. In the environment of fatigue loads acting on the hull, the delaminations propagate and lead to the loss of load capacity of the hull structure. There is a need to improve diagnostic systems used in Structural Health Monitoring (SHM) of laminate hull elements to detect and monitor the development of the delaminations. Effective diagnostic systems used for delamination assessment base on expert systems. Along with other tools, the expert diagnostic advisory systems make use of the non-destructive examination method which consists in generating elastic waves in the hull shell structure and observing their changes by comparing the recorded signal with damage patterns collected in the expert system database. This system requires introducing certain patterns to its knowledge base, based on the results of experimental examinations performed on specimens with implemented artificial delaminations. The article presents the results of the examination oriented on assessing the delaminations artificially generated in the structure of glass- and carbon-epoxy laminates by introducing local non-adhesive layers with the aid of thin polyethylene film, teflon insert, or thin layer of polyvinyl alcohol. The efficiency of each method was assessed using laser vibrometry. The effect of the depth of delamination position in the laminate on the efficiency of the applied method is documented as well.

Parole chiave

  • watercraft hull
  • laminate
  • artificial delamination
  • SHM diagnostics
  • advisory expert system knowledge base
Accesso libero

Study of Harmonic Detection Methods under Non-Ideal Conditions in Ship Power Network

Pubblicato online: 15 Oct 2015
Pagine: 82 - 89

Astratto

Abstract

An improved harmonic detection method based on average arithmetic is proposed. According to the research results, the designed solution uses an LPF (low-pass-filter) and a mean value module connected in series instead of the conventional mean value module, and simultaneously, a three-phase voltage phase-locked module instead of commonly used PLL (phase lock loop) module is applied in order to reduce the influence caused by three-phase distorted voltage and rapid variation of load. The experimental results show that the application of this solution leads to increase in the accuracy of harmonics detection for distorted three-phase voltage and rapid variation of load.

Parole chiave

  • distorted three-phase voltage
  • rapid-variation load
  • harmonic detection
  • average arithmetic
Accesso libero

An Experimental Study of Emission and Combustion Characteristics of Marine Diesel Engine in Case of Cylinder Valves Leakage

Pubblicato online: 15 Oct 2015
Pagine: 90 - 98

Astratto

Abstract

Presented paper shows the results of the laboratory tests on the relationship between throttling of both air intake duct and exhaust gas duct and a gaseous emission from the marine engine. The object of research is a laboratory, four-stroke, DI diesel engine, operated at loads from 50 kW to 250 kW at a constant speed equal to 750 rpm. During the laboratory tests over 50 parameters of the engine were measured with its technical condition recognized as a „working properly” and with simulated leakage of both air intake valve and exhaust gas valve on the second cylinder. The results of this laboratory research confirm that the leakage of cylinder valves causes no significant changes of the thermodynamic parameters of the engine. Simulated leakages through the inlet and exhaust valve caused a significant increase in fuel consumption of the engine. Valve leakages cause an increase of the exhaust gas temperature behind the cylinder with leakage and behind other cylinders. The exhaust gas temperature increase is relatively small and clearly visible only at low loads of the engine. The increase of the temperature and pressure of the charging air behind the intercooler were observed too. Charging air temperature is significantly higher during the engine operation with inlet valve leakage. The study results show significant increases of the CO, NOx and CO2 emission for all the mentioned malfunctions. The conclusion is that the results of measurements of the composition of the exhaust gas may contain valuable diagnostic information about the technical condition of the air intake duct and the exhaust gas duct of the marine engine.

Parole chiave

  • marine diesel engine
  • exhaust gas composition
  • emission
  • exhaust gas valve leakage
  • inlet valve leakage
Accesso libero

Tryton Supercomputer Capabilities for Analysis of Massive Data Streams

Pubblicato online: 15 Oct 2015
Pagine: 99 - 104

Astratto

Abstract

The recently deployed supercomputer Tryton, located in the Academic Computer Center of Gdansk University of Technology, provides great means for massive parallel processing. Moreover, the status of the Center as one of the main network nodes in the PIONIER network enables the fast and reliable transfer of data produced by miscellaneous devices scattered in the area of the whole country. The typical examples of such data are streams containing radio-telescope and satellite observations. Their analysis, especially with real-time constraints, can be challenging and requires the usage of dedicated software components. We propose a solution for such parallel analysis using the supercomputer, supervised by the KASKADA platform, which with the conjunction with immerse 3D visualization techniques can be used to solve problems such as pulsar detection and chronometric or oil-spill simulation on the sea surface.

Parole chiave

  • supercomputer
  • data streams
  • distributed systems
  • radio-telescope
  • satellite

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