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Wyniki wyszukiwania dla: EXTREME SHIP RESPONSE
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Analysis of the Possibilities of Applying 3D Print Methods for the Needs of Ship-Building Industry
PublikacjaArticle presents the analysis of applying additive and hybrid manufacturing methods and its impact on dynamic stiffness of prepared samples. Dynamic analysis of the handle bracket specimens consisted in plotting the resonance curves and using these curves to estimate the dynamic stiffness of elements produced with additive manufacturing technology. Authors focused especially on 3D print in Fused Deposiotion Modeling/Fused Filament...
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Ship weather routing optimization with dynamic constraints based on reliable synchronous roll prediction
PublikacjaShip routing process taking into account weather conditions is a constrained multi-objective optimization problem and it should consider various optimization criteria and constraints. Formulation of a stability-related, dynamic route optimization constraint is presented in this paper. One of the key objectives of a cross ocean sailing is finding a compromise between ship safety and economics of operation. This compromise should...
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A ship domain-based model of collision risk for near-miss detection and Collision Alert Systems
PublikacjaThe paper presents a new model of ship collision risk, which utilises a ship domain concept and the related domain-based collision risk parameters. An encounter is here described by five variables representing: degree of domain violation (DDV), relative speed of the two vessels, combination of the vessels’ courses, arena violations and encounter complexity. As for the first three variables, their values can be directly computed...
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A multiparameter simulation-driven analysis of ship turning trajectory concerning a required number of irregular wave realizations
PublikacjaIn times of progressive automation of the marine industry, accurate modeling of ship maneuvers is of utmost importance to all parties involved in maritime transportation. Despite the existence of modern collisionavoidance algorithms using 6DOF motion models to predict ship trajectories in waves, the impact of stochastic realization of irregular waves is usually neglected and remains under-investigated. Therefore, herein, this phenomenon...
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Jerzy Kowalski dr hab. inż.
Osoby -
Pial artery and subarachnoid width response to apnoea in normal humans
PublikacjaBackground: Little is known about intracranial pressure (ICP)-cerebral haemodynamic interplay during repetitive apnoea. A recently developed method based on near-infrared transillumination/backscattering sounding (NIR-T/BSS) noninvasively measures changes in pial artery pulsation (cc-TQ) as well as subarachnoid width (sas-TQ) in humans. Method: We tested the complex response of the pial artery and subarachnoid width to apnoea...
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Fatigue of the ship structure.
PublikacjaZaprezentowano wyniki prac badawczych zachowania paneli SANDWICH pod obciążeniem zginającym. Prace prowadzone były w Kat. Technol. Okrętów i Obiektów Oceanotechn. Wydz. OiO i obejmowały między innymi badania konstrukcji w skali rzeczywistej. Dokonano porównania uzyskanych rezultatów z wynikami prezentowanymi w literaturze.
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Machine learning-based seismic response and performance assessment of reinforced concrete buildings
PublikacjaComplexity and unpredictability nature of earthquakes makes them unique external loads that there is no unique formula used for the prediction of seismic responses. Hence, this research aims to implement the most well-known Machine Learning (ML) methods in Python software to propose a prediction model for seismic response and performance assessment of Reinforced Concrete Moment-Resisting Frames (RC MRFs). To prepare 92,400 data...
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The Conception of Decision-Making Support System for ComplexEnergetic System on Example of Ship Propulsion System
PublikacjaIn paper, the conception of decision-making support system for complex energetic system on example of ship propulsion system has been presented. Diversity of conditions, information overload and very often contradiction of decision-making criteria and time constraints result in difficulties in making right (rational) decision without using more or less expanded information processing systems (eg. database systems, expert systems,...
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Path planning algorithm for ship collisions avoidance in environment with changing strategy of dynamic obstacles
PublikacjaIn this paper a path planning algorithm for the ship collision avoidance is presented. Tested algorithm is used to determine close to optimal ship paths taking into account changing strategy of dynamic obstacles. For this purpose a path planning problem is defined. A specific structure of the individual path and fitness function is presented. Principle of operation of evolutionary algorithm and based on it dedicated application...
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Rapid antenna design optimization using shape-preserving response prediction
PublikacjaAn approach to rapid optimization of antennas using the shape-preserving response-prediction (SPRP) technique and coarsediscretization electromagnetic (EM) simulations (as a low-fidelity model) is presented. SPRP allows us to estimate the response of the high-fidelity EM antenna model, e.g., its reflection coefficient versus frequency, using the properly selected set of so-called characteristic points of the low-fidelity model...
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Response features for fast EM-driven design of miniaturized impedance matching transformers
PublikacjaA framework for low-cost EM-driven design optimization of compact impedance matching transformers is presented. Our technique is based on a bottom-up design where design requirements for the transformer circuit are translated into specifications for its building blocks. These elementary cells are optimized using response features. Subsequently, the entire circuit is fine-tuned using local response surface approximation models and...
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Simulation of ship spiral test for ballast and full load conditions
Dane BadawczeThe data show the results of the spiral test for the simplified ship model, taking into account two states of loading: ballast and full load. The data set contains the results of time simulation for sea state 10 on the Beaufort scale: changes in rudder angle delta_tab[deg]; angular velocity r_tab[deg/s]; surge velocity u_tab (m/s); sway velocity v_tab...
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A method of determining and visualizing safe motion parameters of a ship navigating in restricted waters
PublikacjaThe paper presents a method of displaying ship collision avoidance information which is based on an unconventional Collision Threat Parameters Area (CTPA) technique. The solution presented here extends CTPA's functionality from past works by supporting navigation in restricted waters and handling ship domains analytically instead of numerically. It visualizes potential navigational threats as well as possible collision avoidance...
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Mohammad Hossein Ghaemi dr inż.
OsobyMohammad Hossein Ghaemi (ur. 1967), adiunkt Wydziału Oceanotechniki i Okrętownictwa (WOiO) PG w Katedrze Automatyki i Energetyki. Jest absolwentem Uniwersytetu Teherańskiego z zakresu mechaniki ciała stałego, a także PG na kierunku Oceanotechnika. Uzyskał stopień doktora nauk technicznych na PG w 2004 roku. Od 1995 roku pracuje na WIMiO PG (do 2020 r. WOiO PG) i prowadzi zajęcia dydaktyczne i badania naukowe w zakresie automatyki...
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Quick Response Manufacturing - sem VI - sem LETNI 2021/2022
Kursy Online -
Transient response of oscillated carbon nanotubes with an internal and external damping
PublikacjaThe present works aims at modeling a viscoelastic nanobeam with simple boundary conditions at the two ends with the introduction of the Kelvin-Voigt viscoelasticity in a nonlocal strain gradient theory. The nanobeam lies on the visco-Pasternak matrix in which three characteristic parameters have a prominent role. A refined Timoshenko beam theory is here applied, which is only based on one unknown variable, in accordance with the...
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DOSE-RESPONSE
Czasopisma -
ADAPTIVE IDENTIFICATION OF TIME-VARYING IMPULSE RESPONSE OF UNDERWATER ACOUSTIC COMMUNICATION CHANNEL
PublikacjaThe transmission properties of underwater acoustic communication channel can change dynamically due to the movement of acoustic system transmitter and receiver or underwater objects reflecting transmitted signal. The time-varying impulse response measurement and estimation are necessary to match the physical layer of data transmission to instantaneous channel propagation conditions. Using the correlative measurement method, impulse...
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Some aspects of noise generated by a small ship in the shallow sea
PublikacjaThe passing and underwater moving objects produce the noises of variable intensity, which significantly increase the overall level of noise in the sea. This applies to both the sonic and ultrasonic range. The excessive levels of underwater noise adversely affects the so-called underwater acoustic climate and is the reason why this phenomenon is intensively investigated from the number of years. The results of experimental work...
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Frequency response spectra applied to assess efficiency of the training techniques
PublikacjaThe purpose of the research is to assess the increase of the muscle strength and power. Movement of the human body when the moving one impacts a stationary or moving body is taken under consideration. The waveform produced by an impact is transformed into frequency domain. The acceleration record is transformed as a complex spectrum, by the use of a Discrete Fourier Transformation. In this paper the applications of the discrete...
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The influence of the geographic positioning system error on the quality of ship magnetic signature reproduction based on measurements in sea conditions
PublikacjaIn previous studies, the authors performed the magnetic signature reconstruction of the marine ship Zodiak as part of the measurement campaign focused on recording magnetic data and the relative position of a ship during its passage over a magnetometer immersed on the testing ground. A high degree of representation of the magnetic signature was obtained. However, the recorded measurement data revealed new patterns of the multidipole model...
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Determining and visualizing safe motion parameters of a ship navigating in severe weather conditions
PublikacjaThe paper presents a method of determining, organizing and displaying ship collision avoidance information, which is based on the Collision Threat Parameters Area (CTPA) technique. The method makes it possible to visualize navigational threats as well as possible collision avoidance manoeuvres. The solution is focused on supporting navigation in severe weather conditions. Normally collision avoidance decisions are made taking into...
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Implicit versus explicit finite volume schemes for extreme, free surface water flow modelling.
PublikacjaPrzedstawiono jeden jawny i trzy niejawne schematy metody objętości skończonych. Porównano własności tych schematów oraz oceniono możliwości ich stosowania do modelowania gwałtownych przepływów w kanałach otwartych. Zaproponowano modyfikację schematu niejawnego. Poprawiony schemat może być stosowany do obliczeń przepływu szybkozmiennego w kanałach otwartych i w sieciach kanalizacyjnych.
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The use of Response Surface Methodology for reliability estimation of composite engineering structures
PublikacjaStability loss is one of the key issues in the analysis of shells made of composite materials. This paper aims at finding the variation of the critical or limit value of the load resulting from geometric imperfections. An axially compressed 16-layer cylindrical panel model is considered. The imperfections of the panel are simulated as random fields. The parameters of these fields are used as the basic variables of the reliability...
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Analysis of the effect of the seismic gap on the response of buildings experiencing pounding during earthquakes
PublikacjaThe aim of this paper is to investigate the effect of the seismic gap on the dynamic response of buildings experiencing earthquake-induced pounding. Three buildings have been analysed, which are 5-storey, 7-storey and 9-storey structures. Three possible pounding scenarios have been considered, which are pounding between 5-storey and 7-storey buildings, pounding between 5-storey and 9-storey buildings and pounding between 7-storey...
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Negative impact of constant RPM control strategy on ship NOx emission in waves
PublikacjaIn severe wave conditions, the ship propulsion system is loaded with high fluctuations due to external disturbances. The highly fluctuating loads enforce radical changes in the main engine torque, which in turn demands variation of the fuel rate injected into the cylinders if a constant rotational speed strategy is applied. Therefore, the temperature of gases varies to a large extent during the combustion process in the cylinders....
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TIME-DOMAIN NUMERICAL EVALUATION OF SHIP RESISTANCE AND MOTION IN REGULAR WAVES BY USING THE CFD URANS METHOD
PublikacjaTaking into account the International Maritime Organisation’s (IMO) strategy to radically reduce the GHG emitted by the shipping industry towards zero emission operation, today's assessment of ship behaviour in waves, its seakeeping characteristics and resistance and their interrelation with fuel consumption and emissions are one of the most attended research subject. There are three methods to conduct this analysis, which are...
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Measurements of the fundamental harmonic frequency of voltages on main bars in a ship power station
Dane BadawczeThe presented dataset is part of research focusing on the assessment of metrological properties of the instrument, Estimator/Analyzer (E/A v.2), developed and made at the Faculty of Electrical Engineering, Department of Marine Electrical Power Engineering of Gdynia Maritime University. The attached dataset contains processed data, expressing the fundamental...
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Scale effect in the self-propulsion prediction for Ultra Large Container Ship with contra-rotating propellers
PublikacjaThis article addresses the problem of the scale effect for an Ultra Large Container Ship (ULCS) with a novel twin-crp-pod propulsion system. Twin-crp-pod steering-propulsion arrangement is an innovative solution that gains from three well-known systems: twin-propeller, contra-rotating propellers and pod propulsors. It is expected that applying the twin-crp-pod system to the analysed Ultra Large Container Ship will increase propulsion...
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Trajectory planning for Service Ship during emergency STS transfer operation
PublikacjaIn this paper trajectory for approaching during emergency STS transfer operation with oil spill is considered as a sequence of navigation manoeuvres in specific navigational environment. The designed way points - ship positions and speed are determined as reference values to support navigator in decision making during steering and to mitigate the risk of collision which mostly results from exceeding the speed limit of approaching....
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Reliable Microwave Modeling By Means of Variable-Fidelity Response Features
PublikacjaIn this work, methodologies for low-cost and reliable microwave modeling are presented using variable-fidelity response features. The two key components of our approach are: (i) a realization of the modeling process at the level of suitably selected feature points of the responses (e.g., S-parameters vs. frequency) of the structure at hand, and (ii) the exploitation of variable-fidelity EM simulation data, also for the response...
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The Unfolded Protein Response: A Double-Edged Sword for Brain Health
PublikacjaEfficient brain function requires as much as 20% of the total oxygen intake to support normal neuronal cell function. This level of oxygen usage, however, leads to the generation of free radicals, and thus can lead to oxidative stress and potentially to age-related cognitive decay and even neurodegenerative diseases. The regulation of this system requires a complex monitoring network to maintain proper oxygen homeostasis. Furthermore,...
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Evolutionary Ship Track Planning within Traffic Separation Schemes – Evaluation of Individuals
PublikacjaThe paper presents an extended version of the author’s Evolutionary Sets of Safe Ship Trajectories method. The method plans safe tracks of all ships involved in an encounter including speed reduction manoeuvres, if necessary, and taking into account Rule 10 of COLREGS, which specifies ships’ behaviour within Traffic Separation Schemes governed by IMO. The paper focuses on the evaluation phase of the evolutionary process and shows...
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A Ship Domain-Based Method of Determining Action Distances for Evasive Manoeuvres in Stand-On Situations
PublikacjaA ship encounter can be considered safe if neither of ships’ domains (defined areas around ships) is intruded by other ships. Published research on this includes optimising collision avoidancemanoeuvres fulfilling domain-based safety conditions.However, until recently there was no method, using ship’s domain to determine exact moment when a particular collision avoidance manoeuvre can still be successfully performed. The authors...
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Monitoring of Caged Bluefin Tuna Reactions to Ship and Offshore Wind Farm Operational Noises
PublikacjaUnderwater noise has been identified as a relevant pollution affecting marine ecosystems in different ways. Despite the numerous studies performed over the last few decades regarding the adverse effect of underwater noise on marine life, a lack of knowledge and methodological procedures still exists, and results are often tentative or qualitative. A monitoring methodology for the behavioral response of bluefin tuna (Thunnus thynnus)...
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Correlated Particle Motion and THz Spectral Response of Supercritical Water
PublikacjaMolecular dynamics simulations of supercritical water reveal distinctly different distance-dependent modulations of dipolar response and correlations in particle motion compared to ambient conditions. The strongly perturbed H-bond network of water at supercritical conditions allows for considerable translationaland rotational freedom of individual molecules. These changes give rise to substantially different infrared spectra and...
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Numerical study on seismic response of a base-isolated building modelled with shell elements
PublikacjaSeismic isolation is counted among the most popular and effective means of protecting structures against earthquake forces. Base isolators, like Lead-Rubber Bearings (LRB), High-Damping Rubber Bearings (HDB) or Friction Pendulum Systems (FPS) are extensively used in practice in many earthquake-prone regions of the world. The present paper reports the results obtained from the numerical study on seismic response of a base-isolated...
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Measurement of Impulse Response of Shallow Water Communication Channel by Correlation Method
PublikacjaPerformances of underwater acoustic communication (UAC) systems are strongly related to specific propagation conditions of the underwater channel; conditions that can additionally change in time due to the movement of the acoustic system transmitter and receiver or to reflection by underwater objects of the transmitted signal. The time-varying impulse response is a comprehensive description of dynamically changing transmission...
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The Analysis of Overall Ship Fuel Consumption in Acceleration Manoeuvre using Hull-Propeller-Engine Interaction Principles and Governor Features
PublikacjaThe problem of reduction of greenhouse gas emissions in shipping is currently addressed by many research works and related industries. There are many existing and visionary technologies and ideas, which are conceptually defined or practically realised. This goal can be achieved in different ways, and reducing fuel consumption is one of the major methods. In these circumstances, the aim of this study is to analyse the possibility...
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Methods of determination of C coefficient for period of rolling vessel in calm water for example of pax cargo ship
PublikacjaThis article presents a different approach to calculate the C coefficient needed to determine the period of own rolling vessel in calm water. The C coefficient is usually adopted as the approximate value from the available literature, usually depending on the type of vessel, and less dependent on the loading condition. In experimental studies of marine properties (seakeeping) often have a problem with the selection of the correct...
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USEFULNESS OF SEMI-MARKOV PROCESSES AS MODELS OF THE OPERATION PROCESSES FOR MARINE MAIN ENGINES AND OTHER MACHINES OF SHIP POWER PLANTS
PublikacjaThe paper describes the properties of semi-Markov processes and the opportunities and benefits from their use as models of the operation processes for marine combustion engines and other machines of ship power plants. The emphasis is put on the importance of the theory of semi-Markov processes for development of the theory of marine combustion engines and other machines of ship power plants, as well as for development of the operational...
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Ship domain applied to determining distances for collision avoidance manoeuvres in give-way situations
PublikacjaShip domain is often used in marine navigation and marine traffic engineering as a safety condition. The basic idea behind those applications is that an encounter of two or more ships can be considered safe if neither of ship domains is intruded by other ships. Research utilising this approach has been documented in numerous works, including publications on optimising collision avoidance manoeuvres performed to fulfil domain-based...
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Problems of Determination of Welding Angular Distortions of T-fillet Joints in Ship Hull Structures
PublikacjaShip hull structure elements are in majority joined by welding. Welding distortions can cause a lot of problems during the manufacturing process. In the literature it is proposed wide spectrum of suggestions for a correct estimation of welding deformation in particular angular deformation in the fillet welded T joint. In the work verification of selected methods is proposed basing upon of the results of the laboratory measurements....
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Effects of Column Base Flexibility on Seismic Response of Steel Moment-Frame Buildings
PublikacjaSteel Moment Resisting Frames (SMRFs) are very popular lateral load resisting systems in many seismically active regions. However, their seismic response is strongly dependent on the rotational fixity of column base connections. Despite many studies (both experimental and numerical) in this particular area, available approaches for estimating column base flexibility have been validated only against laboratory test data. In the...
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Wavelet Transform Analysis of Temperature Modulated Gas Sensor Response
PublikacjaThe aim of the study was to evaluate whether it is possible to extract the information about the gas concentration despite the influence of humidity. Commercial semiconductor sensor response was examined under the application of a periodic temperature change. The data was collected using measurement protocol for different concentrations of ammonia at specified levels of relative humidity. In this work we focused on the evaluation...
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A framework to analyse the probability of accidental hull girder failure considering advanced corrosion degradation for risk-based ship design
PublikacjaShip’s hull girder failure could result from maritime accident that can cause human life loss, environmental disaster, and major economic impacts. In risk-based ship design paradigm, accounting for rare phenomena (e.g. ship-ship collision or grounding) is important to provide safe and durable structure. In-service corrosion-induced hull degradation should be considered at the design stage, as it can significantly affect structural...
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Application of Maximum-Length Sequences to impulse response measurement of hydroacoustic communications systems
PublikacjaThere is a growing interest in digital transmission of telemetry data on ultrasonic waves. The dependence of signal attenuation on squared frequency, specific to the hy-droacoustic systems, induces problems that do not exist in monochromatic, narrowband radio communications systems. For adapting the transmission parameters to current propagation conditions, a precise knowledge of instantaneous changes of channel performances is...
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Multiobjective Aerodynamic Optimization by Variable-Fidelity Models and Response Surface Surrogates
PublikacjaA computationally efficient procedure for multiobjective design optimization with variable-fidelity models and response surface surrogates is presented. The proposed approach uses the multiobjective evolutionary algorithm that works with a fast surrogate model, obtained with kriging interpolation of the low-fidelity model data enhanced by space-mapping correction exploiting a few high-fidelity training points. The initial Pareto...
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THE POSSIBILITIES OF ESTIMATING THE RELIABILITY OF SHIP PIPELINES’ ELEMENTS INCLUDING DESTRUCTIVE PHENOMENA ACTING ON THEM
PublikacjaIn the article an approach to the problem of estimating reliability data based on physical models is proposed. The possibility of reliability assessment for selected elements of ship pipelines, based on the recognition of the destructive physical phenomena taking place in them, is discussed. To do this, an overview of these phenomena has been made. In addition, a preliminary review of existing measures of destruction of materials...