Ship Components Research Articles

Study on the Corrosion Resistance of Laser Clad Al0.7FeCoCrNiCux High-Entropy Alloy Coating in Marine Environment

In the marine atmosphere, the corrosion rate of ship components is 4–5 times higher than that of the inland atmosphere. To solve the serious corrosion problem arising from long-term service in the marine environment of naval aircraft and ships, etc., this paper takes Al0.7FeCoCrNiCux system high-entropy alloy coating prepared by laser melting technology with 5083 aluminum alloys as the base material and analyzes the aging and failure mode of equipment coating under a marine atmospheric environment. XRD and SEM were utilized to study the microscopic morphological structure of the coatings. The laws of influence of Cu elements on the electrochemical corrosion behavior of the Al0.7FeCoCrNiCux system high-entropy alloy in 3.5 wt.% NaCl neutral solution was investigated by using dynamic potential polarization and electrochemical impedance spectroscopy, and neutral salt spray acceleration tests and outdoor atmospheric exposure tests were carried out. The results show that the Al0.7FeCoCrNiCux (x = 0) high-entropy alloy coating has a single BCC phase structure and the Al0.7FeCoCrNiCux (x = 0.30, 0.60, 0.80, 1.00) high-entropy alloy coating consists of both BCC and FCC phases with a typical dendrite morphology. With the increase in Cu content, the self-corrosion potential of Al0.7FeCoCrNiCux gradually increases and the current density gradually decreases, which with the results of the electrochemical impedance spectrum analysis, indicating that the corrosion resistance of Al0.7FeCoCrNiCu1.00 is optimal. The results of the neutral salt spray acceleration test and the outdoor atmospheric exposure test were integrated to conduct a comprehensive evaluation of the corrosion resistance of the coating. The corrosion resistance of Al0.7FeCoCrNiCux coating increases with the increase in Cu content, and the impressive strength and plastic deformation are best when x = 0.80. Neutral salt spray accelerated the test with no corrosion at 5040 h, and even if the coating is broken, it can last up to 4320 h. In the outdoor atmospheric exposure test, which was conducted 12 months after the coating surface test, no corrosion occurred.

Microstructure, mechanical properties, and cavitation erosion performances of cold sprayed CuZn35 coatings

CuZn alloy (as known as brass) is widely used in ship components due to its combination of high hardness and fatigue strength, and therefore good cavitation erosion performance. In this study, CuZn35 powder was for the first-time cold spray deposited on pure aluminum substrates for potential application as cavitation protection of hull pipelines. Parametric studies were carried out and the respective deposition characteristics were analyzed, and cavitation erosion performances of different CuZn35 coatings were characterized in deionized water using ultrasonic vibration experiments. The results showed that with the increase of gas temperature, cold sprayed CuZn35 coatings generally showed better cold sprayability and coating performance on aluminum substrates. The cold sprayed CuZn35 coatings exhibited a dense structure (porosity ~0.43 %), fine grain (~0.549 μm), a relatively high microhardness (~226 HV), and a relatively high bonding strength (54 MPa). The cavitation resistance of cold sprayed CuZn35 coatings showed a lowest volume loss rate of 0.22 mm3/h in deionized water, which was lower than that of as-cast CuZn35 (0.39 mm3/h). After 120 min cavitation, various features such as undulation deformation, pit and crack propagation, and material peeling appeared on cold sprayed CuZn35 coatings. It was noted that cold sprayed CuZn35 coatings, different from the as-cast CuZn35, exhibited the main cavitation mechanism of delamination caused by interlayer crack propagation.

이기종 CAD 시스템에서 설계된 엘보우 파이프 모델의 통합을 위한 부분 토러스 재건

For constructing various geometric shapes of ship components, computer-aided design (CAD) models need to be integrated into shipbuilding CAD systems. As package models provided by CAD solution vendors are designed using mechanical CAD systems, complex triangular meshes have a serious impact on the modeling performance. In particular, reconstructing the elbow pipe represented by triangular meshes in a shipbuilding model is a difficult problem. We present a method to reconstruct elbow primitives for the Plant Design Management System (PDMS) from triangular meshes using mesh segmentation and elbow parameter extraction methods. The mesh segmentation method divides the mesh of irregular and minimal 3D points into segments for elbow parameter extraction based on curvature and face normal vector. The proposed method could also enable to extract parameters for the elbow pipe by using the geometrical features of the partial torus. As a result of the experiment, the average reconstruction difference is 2.278㎜, which showed that the proposed method can be applied to integration of elbow pipe models designed in heterogeneous cad systems.

Analysis of Variational Autoencoders for Imputing Missing Values from Sensor Data of Marine Systems

Of all the causes of accidents to ships, 14% pertains to damage due to ship equipment. Accordingly, the maritime industry is currently considering state-of-the-art maintenance and inspection processes, an example of which is condition-based maintenance (CBM). This is a strategy that hinges on the condition monitoring (CM) of assets. CM has proven to increase efficiency, reliability, profitability, and performance of vessel. To enable this maintenance strategy, sensors need to be installed along the most critical ship components and around the environment where these assets are operating through the application of Internet of Ships (IoS). IoS has demonstrated to be effective for collecting data in real time as well as performing diagnosis and prognosis to assess the current and future health of machinery to assist instant decision-making. The employment of IoS presents several challenges, an example of which is the imputation of missing values. Data imputation is a compelling preprocessing step, the aim of this is to estimate identified missing values to avoid underutilization of data. This data preparation step has gained popularity over the last few years due to its importance when dealing with Industrial Internet of Things (IIoT) sensor data. Although some articles presented new methodologies to impute missing values from sensor data of marine machinery based on machine learning methodologies, deep learning models have not yet been considered. For this reason, variational autoencoders for imputing missing values from sensor data of marine systems are analyzed in this article. To assess the performance of variational autoencoders as imputation methods, a comparative study is performed with widely implemented imputation techniques. Mean imputation, Forward Fill and Backward Fill, and k-Nearest Neighbors are considered. To that end, a case study on marine machinery system parameters obtained from sensors installed on a diesel generator of a tanker ship is performed. Results demonstrate the applicability of variational autoencoders when dealing with missing values of marine machinery systems sensor data, achieving a coefficient of determination of 0.99 when imputing missing values of the diesel generator power parameter.

AUTOMATED GENERATION AND LOW-EFFORT AUTHORING OF COMMISSIONING CONTENT IN THE MARITIME INDUSTRY

Commissioning in the maritime industry is a long crucial phase in which all essential components in the ship are tested for faults and defects before a final acceptance form is signed by the client. Due to the variety of components in a ship and the complex hierarchical structure of such components, it is typical to have thousands of tests that should be performed throughout the commissioning phase. For every new ship, commissioning planners initially spend hours preparing the commissioning tests by reading technical documents, extracting relevant information, and applying the gathered knowledge to the unique equipment configuration in the ship. This leads to high preparation efforts and planning mistakes, e.g., unconsidered dependencies, and as a result, commissioning, and the shipbuilding process as a whole may be delayed. This paper lays the foundation for automating the process of authoring commissioning content for maritime productions. The paper presents a digital modeling approach for ship components, which facilitates the development of commissioning-specialized software. The model shown in this paper takes textual and geometrical information of ship components as input data and produces generalized commissioning templates that can be used to generate commissioning tests automatically.

Numerical Investigation of the Effect of Surface Roughness on the Viscous Resistance Components of Surface Ships

Numerical Investigation of the Effect of Surface Roughness on the Viscous Resistance Components of Surface Ships

Research on Rigid-flexible Coupling Dynamic Modeling and Dynamic Characteristics Based on Tremmie Pipe

The tremmie pipe is the key structural component of the rubble leveling ship. Its vibration affects the laying accuracy of the rubble leveling ship. The 3D structural model of the tremmie pipe ship is established with the help of the 3D modeling software SolidWorks, and the tremmie pipe is flexible by ANSYS. The rigid-flexible coupling dynamics model is built in ADAMS. Apply constraints and external excitation of the pipe end, carry out modal analysis and dynamic simulation analysis on the model, study the dynamic characteristics of the tremmie pipe during the tremmie pipe process, provide the basis for structural vibration control, and have guiding significance for the optimal design of the tremmie pipe.

Getaran Torsional Sistem Propulsi Kapal Tug Boat

The Torsional Vibration of Propulsion System of the Tug Boat Ship. Vibrations that occur in the ship's propulsion system can cause reduced operating capability and cause damage to the ship's components, one of the vibrations that occur in the ship's propulsion system is torsional vibration. The purpose of this study was to determine the value of torque oscillations in Tugboat Ship propulsion systems and to find out the value of noise radiation following ICES 209 standard with variations of ST 60 steel material, stainless steel, and carbon steel, using analitical methods. The results obtained by the torque oscillation value of the propulsion system from Tugboat Ship BPW 3 with the variation of ST 60 steel material is 0.0004854, while for carbon steel material, the torque oscillation value is 0.0004690 and the propulsion system that uses stainless steel material variation is 0.0004527. The level of noise radiation (SL) that occurs in propulsion systems using variations of ST 60 steel material is 133.22 dB, while for carbon steel material is 133.23 dB and for stainless steel material is 133.25 dB, of the three noise radiation values (SL ) produced, is still included in the ICES 209 noise level standard.

EV's Impact on Packaging

Electric vehicle ownership and usage is driving more OEMs and part suppliers to reconsider the way they package and ship components

Fatigue Collapse of Ship Structural Components: a Case Study

Most damages to structural components of ships are due to fatigue phenomena. Particular care should then be devoted to fatigue evaluation since the first phases of any ship project. All main Classification Societies have in their Rules simplified procedures for fatigue evaluation, in order to make all designers able to perform structure scantling complying with fatigue principles. Apart from design necessities, there is another aspect for which it becomes important to assess and evaluate fatigue phenomena; this happens when it is necessary to ascertain the causes of occurred an accident. While for design purposes the aim is to calculate the fatigue life of a structural detail based on a probabilistic approach, in the case of an occurred accident the driving philosophy is to accurately analyse the life history of the structure and to calculate, by a deterministic approach, the cumulative damage of the component up to the event time. The aim of this paper is to set up a procedure to analyse and verify the causes of the failure of a ship structure component due to fatigue phenomena.

Process knowledge graph modeling techniques and application methods for ship heterogeneous models

In the process design and reuse of marine component products, there are a lot of heterogeneous models, causing the problem that the process knowledge and process design experience contained in them are difficult to express and reuse. Therefore, a process knowledge representation model for ship heterogeneous model is proposed in this paper. Firstly, the multi-element process knowledge graph is constructed, and the heterogeneous ship model is described in a unified way. Then, the multi-strategy ontology mapping method is applied, and the semantic expression between the process knowledge graph and the entity model is realized. Finally, by obtaining implicit semantics based on case-based reasoning and checking the similarity of the matching results, the case knowledge reuse is achieved, to achieve rapid design of the process. This method provides reliable technical support for the design of ship component assembly and welding process, greatly shortens the design cycle, and improves the working efficiency. In addition, taking the double-deck bottom segment of a ship as an example, the process knowledge map of the heterogeneous model is constructed to realize the rapid design of ship process, which shows that the method can effectively acquire the process knowledge in the design case and improve the efficiency and intelligence of knowledge reuse in the process design of the heterogeneous model of a ship.

Realization of optically transparent and broadband frequency selective rasorber using thin copper wire

Numerous studies have been made to design broadband frequency selective rasorber (FSR). However, it is still a challenge to realize optically transparent FSR, due to the difficulty in realizing high transparency, high-quality factor(Q) parallel resonance, and low-Q series resonance simultaneously. Here, we propose a new method to design transparent FSR for the first time. To break through the technical barrier, a thin copper wire with a different configuration method is utilized to design lossy layer, which can realize high transparency, in-band transmission, and out-of-band absorption concurrently. The proposed FSR is configured by cascading a transparent lossy layer above a transparent frequency selective layer with an air space to separate them. We adopt the equivalent circuit model, electric field distribution, and loss distribution to reveal the physical mechanism of the FSR. The simulation results show that the transmission loss is 1 dB at 8.3 GHz, and the reflection amplitude is less than −10 dB in 2.7–8.9 GHz. The FSR can achieve 96.3% optical transparency theoretically. A prototype is fabricated and measured to validate the proposed design. The measured results achieve good agreement with the simulated results. The proposed FSR can act as a stealth radome for transparent components of ships and aircrafts. The application scenarios can be extended to communication and imaging systems.

НОВЫЕ ПЕРСПЕКТИВНЫЕ НАПРАВЛЕНИЯ ТОРГОВО-ЭКОНОМИЧЕСКОГО СОТРУДНИЧЕСТВА РОССИИ В ОБЛАСТИ ГРАЖДАНСКОГО СУДОСТРОЕНИЯ

In the context of sanctions restrictions, the civil shipbuilding industry is facing new challenges related, first of all, to the suspension and denial of supplies of the necessary ship components and materials under existing contracts from foreign partners. As the President of the Russian Federation V.V. Putin at a meeting on the development of the shipbuilding industry, held on August 18, 2022, the replacement of foreign equipment and components in the production of fishing and other civilian vessels may affect the parameters of already launched projects. Corresponding changes are associated with the timing and costs of redesign. Given the long cycle of ship production, it is necessary to set long-term guidelines for the development of shipbuilding, to determine the strategic tasks that the industry will face in the civilian segment.In connection with the significant geopolitical changes taking place today, significant prerequisites are being created for expanding trade and economic cooperation in the field of civil shipbuilding with the BRICS and BRICS + countries.

Import substitution of ship component equipment in the fishing fleet

Статья посвящена вопросам импортозамещения судового комплектующего оборудования на рыбопромысловых судах отечественной постройки Рассмотрены вопросы стандартизации и унификации судового комплектующего оборудования.

Review of the Risk Assessment Methods for Shipbuilding in Indonesia

In the shipbuilding industry, there is still little discussion and analysis of risk management in the shipbuilding process. From previous studies, it is probable that the material/component group has a high percentage of shipbuilding delays, but there are no publications that discuss ship components specifically. Various models have been developed related to risk assessment in shipbuilding, but mostly discussed on shipbuilding construction, company management and work safety in shipyards. This paper discusses the need for planning and risk assessment models for component availability in the construction of new ships in Indonesia. The aim is to review the methods that will be used in risk assessment, combined with quantitative evaluation methods in the procurement of component materials and ship building installations. The development of methods for risk analysis, with a combination of Failure Mode and Effect Analysis (FMEA) and Bayesian Network (BN) approaches, it is hoped that the most critical risks can be identified so that risk evaluation actions can be carried out.

PENGARUH TEMPERATUR TUANG TERHADAP POROSITAS, STUKTUR MIKRO DAN KEKERASAN DARI ALUMUNIUM RONGSOK VELG MENGGUNAKAN PENGECORAN EVAPORATIF

The second largest metal material used after steel is Aluminum and its alloys. Ranging from aircraft bodies, vehicles, engine components, ship components, to buildings and very diverse applications using aluminum alloys. Material for making alloy wheels for components in motors using one of the special aluminum alloy applications with regard to the strength and hardness of high-quality aluminum alloys. Industrial companies that make aluminum doors, including windows and frames, make aluminum shelves, storefronts and other products. Produce waste remnants of used aluminum which can be used as aluminum as the main material destination. To reduce the company's production costs, many of them use aluminium scrap as their main casting material. Casting uses a temperature of 650 ° C, 700 ° C, 750 ° C, 800 ° C including casting type evaporative or casting using Styrofoam. The missing styrofoam casting pattern is a casting that uses a pattern of material that can evaporate when exposed to molten metal heat. The casting temperature results can affect microstructure, hardness, porosity and structure.

Improving shipboard electronics cooling system by optimizing the heat sinks configuration

With the increase of high-power electrical components in modern ships, especially fully electric ships with electric propulsion drive (EPD), the cooling of EPD electrical components has become particularly important. Providing optimal configurations for heat sinks with high thermal efficiency plays an essential role in this regard. A new technique for improving the efficiency of heat sinks is the utilization of perforated fins. This study examined the effects of perforation geometry (shape and size) on laminar airflow flow and heat transfer characteristics over a perforated plate-fin heat sink. Three-dimensional simulations were conducted using the finite-volume scheme based on the SIMPLE algorithm. In this research, the effects of perforation shape and size on various parameters, e.g., total drag force, average Nusselt number, perforated fin efficiency (PFE), heat transfer performance enhancement (HTPE), and fin optimization factor (η) were evaluated. The results confirmed that at a specific heat transfer surface area for perforated fins, the highest efficiency is achieved by circular perforations.In contrast, the square perforations due to geometric similarity to rectangular fins could reach the maximum size. Consequently, fins with square perforations could achieve the most optimal configuration. Also, results showed that for a constant perforations size, change in perforations shape improves HTPE, PFE, and η by more than 40%, 45%, and 110%, respectively. Also, by modifying perforations size for a specified shape, an increment of more than 35%, 40%, and 150% is observed in HTPE, PFE, and η, respectively.

Prediction of fracture toughness of metallic materials

Fracture toughness is a measurement of fracture resistance and is a crucial parameter in designing and manufacturing structural engineering components, including the components of ships and offshore structures. However, accurate measurement of fracture toughness requires a fatigue pre-cracked specimen which can be challenging to prepare in extremely brittle materials. Moreover, specimen thickness is another requirement which can be challenging to achieve as well, particularly in very tough materials. Therefore, a physics-based closed-form analytical expression is proposed to determine fracture toughness of isotropic materials simply by utilizing a uniaxial tensile test specimen. The expression naturally introduces a length scale parameter, consistent with non-local applications, such as peridynamics, as well. Fracture toughness of various metallic materials, including both brittle and ductile, are predicted and compared to the experimental results in the literature. Predicted fracture toughness values are in good agreement with the experimentally measured ones.

Path planning and forming of wire multi-arc additive collaborative manufacture for marine propeller bracket

The propeller bracket is an essential structural component of the large ship, with large structural size, high precision and performance. Multi-arc collaborative additive manufacturing is an effective method for forming high precision and performance large-scale propeller bracket. This paper studies the high-precision and performance multi-arc collaborative additive manufacturing propeller bracket forming strategy and path planning method. In the multi-arc cooperative additive manufacturing of the bracket, the two arcs in the front are used to form the contour of the depositing layer, while the rear three arcs are used to fill the contour. Finally, the five arcs collaborated additive manufacturing bracket is formed. Based on the structural characteristics of the bracket, it is divided into four regions: the hub, support arm, cross arm and intersecting area. The hub is a rotating body of equal thickness and cross-section. The relative positions of the five arcs are fixed, and the path is calculated by adjusting the attitude angle of the device in real-time during the printing process. The intersecting area, support arm and cross arm are all curved bodies with variable thickness and cross-section. The contour torches are used to form the two sides of the contour separately, and then the filling torch is used to variable amplitude swing filling the contour. The five arcs collaborative additive manufacture propeller bracket with a length of 3.5 m is formed by the above forming strategy and path planning method. The forming accuracy of the bracket is ±0.6 mm. The microstructure is composed of pearlite and massive ferrite. The tensile strength is 774 MPa, and the yield strength is 642 MPa. The mechanical properties are higher than the castings one with the same composition, and the forming efficiency reaches 1800 cm3/h.

Technical reliability of shipboard technologies for the application of alternative fuels

BackgroundNaval traffic is highly dependent on depleting fossil resources and causes significant greenhouse gas emissions. At the same time, marine transportation is a major backbone of world trade. Thus, alternative fuel concepts are highly needed. Different fuels such as ammonia, methanol, liquefied natural gas and hydrogen have been proposed. For some of them, first prototype vessels have been in operation. However, practical experience is still limited. Most studies so far focus on aspects such as efficiency and economics. However, particularly in marine applications, reliability of propulsion systems is of utmost importance, because failures on essential ship components at sea pose a huge safety risk. If the respective components lose their functionality, repair can be much more challenging due to large distances to dockyards and the complicated transport of spare parts to the ship. Consequently, evaluation of reliability should be a core element of system analysis for new marine fuels.ResultsIn this study, reliability was studied for four potential fuels. The analysis involved several steps: estimation of overall failure rates, identification of most vulnerable components and assessment of criticality by including severity of fault events. On the level of overall failure rate, ammonia is shown to be very promising. Extending the view over a pure failure rate-based evaluation shows that other approaches, such as LOHC or methanol, can be competitive in terms of reliability and risk. As different scenarios require different weightings of the different reliability criteria, the conclusion on the best technology can differ. Relevant aspects for this decision can be the availability of technical staff, high-sea or coastal operation, the presence of non-naval personnel onboard and other factors.ConclusionsThe analysis allowed to compare different alternative marine fuel concepts regarding reliability. However, the analysis is not limited to assessment of overall failure rates, but can also help to identify critical elements that deserve attention to avoid fault events. As a last step, severity of the individual failure modes was included. For the example of ammonia, it is shown that the decomposition unit and the fuel cell should be subject to measures for increasing safety and reducing failure rates.