China’s shipbuilding industry maintained the world’s largest market share in terms of three major indicators for the 16th consecutive year in 2025,according to data released by the Ministry of Industry and Informati...China’s shipbuilding industry maintained the world’s largest market share in terms of three major indicators for the 16th consecutive year in 2025,according to data released by the Ministry of Industry and Information Technology on 1 February.展开更多
This review article provides a comprehensive analysis of nesting optimization algorithms in the shipbuilding industry,emphasizing their role in improving material utilization,minimizing waste,and enhancing production ...This review article provides a comprehensive analysis of nesting optimization algorithms in the shipbuilding industry,emphasizing their role in improving material utilization,minimizing waste,and enhancing production efficiency.The shipbuilding process involves the complex cutting and arrangement of steel plates,making the optimization of these operations vital for cost-effectiveness and sustainability.Nesting algorithms are broadly classified into four categories:exact,heuristic,metaheuristic,and hybrid.Exact algorithms ensure optimal solutions but are computationally demanding.In contrast,heuristic algorithms deliver quicker results using practical rules,although they may not consistently achieve optimal outcomes.Metaheuristic algorithms combine multiple heuristics to effectively explore solution spaces,striking a balance between solution quality and computational efficiency.Hybrid algorithms integrate the strengths of different approaches to further enhance performance.This review systematically assesses these algorithms using criteria such as material dimensions,part geometry,component layout,and computational efficiency.The findings highlight the significant potential of advanced nesting techniques to improve material utilization,reduce production costs,and promote sustainable practices in shipbuilding.By adopting suitable nesting solutions,shipbuilders can achieve greater efficiency,optimized resource management,and superior overall performance.Future research directions should focus on integrating machine learning and real-time adaptability to further enhance nesting algorithms,paving the way for smarter,more sustainable manufacturing practices in the shipbuilding industry.展开更多
Microstructural evolution features have been systematically investigated for the weld metal of EH36 shipbuilding steel under an in situ confocal scanning laser microscope.The influence of cooling rate on microstructur...Microstructural evolution features have been systematically investigated for the weld metal of EH36 shipbuilding steel under an in situ confocal scanning laser microscope.The influence of cooling rate on microstructural changes during the transformation from austenite to ferrite has been clarified.It is found that ferrite side plates form preceding to acicular ferrites,although the starting temperature of respective component decreases as the cooling rate is raised.In particular,the growth rate of acicular ferrite is measured to increase significantly,rising from 30.4μm/s at a cooling rate of 3 K/s to 109.0μm/s at 15 K/s,driven primarily by an ever-increasing degree of undercooling.These findings highlight the critical role of cooling rate in dictating the sequence and growth rate of microstructural transformations,which is crucial for optimizing welding processes to obtain desired microstructures while avoiding the formation of deleterious components.展开更多
Shipbuilding production management and logistics control are studied so as to find an advanced shipbuilding production logistics management style.The necessity and feasibility to integrate MRP-Ⅱ(manufacture resource ...Shipbuilding production management and logistics control are studied so as to find an advanced shipbuilding production logistics management style.The necessity and feasibility to integrate MRP-Ⅱ(manufacture resource planning)and JIT(just-in-time)are researched properly following the comparison of MRP-Ⅱ and JIT and the analysis of shipbuilding production characteristics.A shipbuilding logistics system combining MRP-Ⅱ with JIT is set up and discussed according to a master production schedule(MPS),MRP and workshop-floor production control.The system is able to simplify the shipbuilding production plan,balance the workshop production,stabilize the supply,and inspire positivity and creativity so as to raise the shipbuilding production management level.展开更多
"China’s shipbuilding industry has boomed in the last 15 years since the end of the 1970s and has drawn attention of international shipbuilding and shipping circles even though a gap still remained between China..."China’s shipbuilding industry has boomed in the last 15 years since the end of the 1970s and has drawn attention of international shipbuilding and shipping circles even though a gap still remained between China and advanced shipbuilding countries including Japan and South Korea. China ranks among advanced shipbuilding countries relying on its own investment and enterprise development. China has opened its shipbuilding industry to the outside world for wider cooperation and more foreign involvement."展开更多
The inclusions evolution behavior in the continuous casting slab, rolled plates, and simulated welding samples of EH36 steels with and without Zr addition has been systematically investigated. The inclusions in plain ...The inclusions evolution behavior in the continuous casting slab, rolled plates, and simulated welding samples of EH36 steels with and without Zr addition has been systematically investigated. The inclusions in plain EH36 steel are almost composed of Al-Ca-S-O（-Mn） and undergo negligible changes during the whole process. With Zr addition, a large amount of individually fine MnS precipitates and Zr-containing inclusions are generated. In the rolled EH36-Zr sample, Zr-containing complex inclusions are effective to promote the nucleation of acicular ferrite on the surface, which are hardly found in the simulated welding sample of EH36-Zr steel due to the segregation of soluble Ti and Zr on the grain boundary.展开更多
Heterogeneous microstructure-induced mechanical responses in EH420 shipbuilding steel welded joint by electro-gas welding processed have been systematically studied by scanning electron microscopy,electron backscatter...Heterogeneous microstructure-induced mechanical responses in EH420 shipbuilding steel welded joint by electro-gas welding processed have been systematically studied by scanning electron microscopy,electron backscatter diffraction and mechanical testing.Comparing with the coarse-grained heat-affected zone(CGHAZ),the weld metal presents higher toughness(129.3 J vs.37.3 J)as it contains a large number of acicular ferrites with high-angle grain boundaries(frequency 79.2%)and special grain boundary∑3(frequency 55.3%).Moreover,coarse austenite grains in CGHAZ and slender martensite–austenite constituents between bainite laths may likely facilitate crack propagation.Polygonal ferrites and tempered pearlites formed at the junction of the fine-grained heat-affected zone and the intercritical heat-affected zone induced a softened zone with an average hardness of 185 HV0.5,which is the main reason for the occurrence of tensile fracture.展开更多
The 6-DOF manipulator provides a new option for traditional shipbuilding for its advantages of vast working space,low power consumption,and excellent flexibility.However,the rotation of the end effector along the tool...The 6-DOF manipulator provides a new option for traditional shipbuilding for its advantages of vast working space,low power consumption,and excellent flexibility.However,the rotation of the end effector along the tool axis is functionally redundant when using a robotic arm for five-axis machining.In the process of ship construction,the performance of the parts’protective coating needs to bemachined tomeet the Performance Standard of Protective Coatings(PSPC).The arbitrary redundancy configuration in path planning will result in drastic fluctuations in the robot joint angle,greatly reducing machining quality and efficiency.There have been some studies on singleobjective optimization of redundant variables,However,the quality and efficiency of milling are not affected by a single factor,it is usually influenced by several factors,such as the manipulator stiffness,the joint motion smoothness,and the energy consumption.To solve this problem,this paper proposed a new path optimization method for the industrial robot when it is used for five-axis machining.The path smoothness performance index and the energy consumption index are established based on the joint acceleration and the joint velocity,respectively.The path planning issue is formulated as a constrained multi-objective optimization problem by taking into account the constraints of joint limits and singularity avoidance.Then,the path is split into multiple segments for optimization to avoid the slow convergence rate caused by the high dimension.An algorithm combining the non-dominated sorting genetic algorithm(NSGA-II)and the differential evolution(DE)algorithm is employed to solve the above optimization problem.The simulations validate the effectiveness of the algorithm,showing the improvement of smoothness and the reduction of energy consumption.展开更多
Recently,there have been the increase of ship size and the development of oil and gas in arctic region.These trends have led to the requirements such as high strength,good toughness at low temperature and good weldabi...Recently,there have been the increase of ship size and the development of oil and gas in arctic region.These trends have led to the requirements such as high strength,good toughness at low temperature and good weldability.The high performance structural steels for shipbuilding and arctic offshore structure have been developed by our own micro-alloying and TMCP technologies.M-A constituent was precisely controlled in the both HAZ and base metal to get high toughness at low temperature.Also,the grain growth of austenite at HAZ was effectively suppressed by thermally stable TiN particles,leading to a good HAZ toughness.On the other hand,there has been the key issue of crack arrestability in large size container ship.The effect of joint design on crack arrestability was investigated to prevent a catastrophic failure along the block joint of hatch side coaming.A brittle crack arrest technique was developed without block joint shift,using an arrest weld in the end of hatch side coaming weld line.展开更多
To manage the complexities of hull module partitions, a new approach to the partitions of hierarchical modules for shipbuilding is proposed. Based on the assembly and manufacture process, the approach determines the h...To manage the complexities of hull module partitions, a new approach to the partitions of hierarchical modules for shipbuilding is proposed. Based on the assembly and manufacture process, the approach determines the hierarchy and basis of the module partition first, and then according to the type of connection between the parts of the block module, the degree of membership for the rational connection is gained and the fuzzy relation matrix between different parts is then established. The fuzzy clustering technique is used to partition the modules, and then the method of fuzzy comprehensive assessment is used to choose a relative reasonable scheme. A case study has been conducted, which proves that the approach is feasible and applicable; Especially it obtains the sub-module partition, which sets up the shipbuilding process at a higher-level assembly and has offered effective tools for the modular ship design.展开更多
The effects of Ca treatment on the particle, microstructure, and toughness of heat-affected zone (HAZ) of shipbuilding steel with Zr-Ti deoxidation after high-heat-input welding were investigated. The simulated weldin...The effects of Ca treatment on the particle, microstructure, and toughness of heat-affected zone (HAZ) of shipbuilding steel with Zr-Ti deoxidation after high-heat-input welding were investigated. The simulated welding at a high-heat-input welding of 200 kJ/cm was carried out using Gleeble-3800 welding simulation. Then, particle characteristics were characterized using an Aztec-Feature automatic particle analysis system. Additionally, an in-situ observation experiment was performed to study the relationships between particle and microstructure by high-temperature confocal laser scanning microscopy (HT-CLSM). The results indicated that the average HAZ toughness at -40 ℃ was increased from 183 to 290 J by adding 0.0026 wt.% Ca. Meanwhile, the formation of acicular ferrite ratio was increased from 49.34% to 60.28% due to the addition of Ca. The scanning electron microscopy results clearly showed that CaO-Al_(2)O_(3)-TiOx-ZrO_(2)-MnS particles could act as effective nucleation sites for the formation of acicular ferrite, which has been verified by the observation of the particle-microstructure relationship under HT-CLSM. Furthermore, particle characterization results show that the cumulative frequency of particles with the size of 1-3 lm was 33.2% in HAZ of Zr-Ti shipbuilding steel but 66.2% in HAZ of Zr-Ti-Ca shipbuilding steel.展开更多
The stretch formability of a low carbon steel processed by friction stir processing （FSP） was studied under biaxial loading condition applied by a miniaturized Erichsen test. One-pass FSP decreased the ferritic grai...The stretch formability of a low carbon steel processed by friction stir processing （FSP） was studied under biaxial loading condition applied by a miniaturized Erichsen test. One-pass FSP decreased the ferritic grain size in the processed zone from 25 μm to about 3 μm, which also caused a remarkable increase in strength values without considerable decrease in formability under uniaxial loading. A coarse-grained （CG） sample before FSP reflected a moderate formability with an Erichsen index （EI） of 2.73 mm. FSP slightly decreased the stretch formability of the sample to 2.66 ram. However, FSP increased the required punch load （FEI） due to the increased strength by grain refinement. FSP reduced considerably the roughness of the free surface of the biaxial stretched samples with reduced orange peel effect. The average roughness value （Ra） decreased from 2.90 in the CG sample down to about 0.65 μm in fine-grained （FG） sample after FSP. It can be concluded that the FG microstructure in low carbon steels sheets or plates used generally in shipbuilding provides a good balance between strength and formability.展开更多
This article explored existing policies (if any) and current management structure which govern operations within the yard, examine some major challenges facing the ship maintenance and repair services in Tema <...This article explored existing policies (if any) and current management structure which govern operations within the yard, examine some major challenges facing the ship maintenance and repair services in Tema </span><span style="font-family:Verdana;">Drydock</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">and Shipbuilding Yard, </span><span style="font-family:Verdana;">Ghana, identif</span><span style="font-family:Verdana;">ied</span><span style="font-family:Verdana;"> few drivers that impact positively on the ship repair market with particular reference to the Tema Shipyard. It concludes by proposing sustainable management and maintenance strategies for improved repair services of the yard as well as analyzing the findings obtained in the data presentation and discussion sections during the research project. The main finding is that the PSC Tema Shipyard’s ship maintenance and repair services are really overwhelmed with major challenges, representing 55% after summing up four (4) out of the seven (7) captured in the study and are threatening its sustainability, if not properly researched and addressed once and for all. As already stated, carefully analysed conclusion</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> w</span><span style="font-family:Verdana;">ere</span><span style="font-family:Verdana;"> drawn to effectively address these challenges, followed by suggestions for future research to forestall its cascading effects on the Ghanaian economy as a </span><span style="font-family:Verdana;">whole.展开更多
Shipbuilding in Bangladesh has been considered as the most promising industry in the recent time and the country is dreaming to emerge as a middle income country within a short time by maintaining the upward trend of ...Shipbuilding in Bangladesh has been considered as the most promising industry in the recent time and the country is dreaming to emerge as a middle income country within a short time by maintaining the upward trend of this sector. However, due to global nature and the long term sustainability of this shipbuilding industry, an investigation of competitiveness in terms of global standard is of prime importance. This paper focuses on studying some crucial competitive factors like labor skill, labor availability, labor man-hour, labor cost ＆ productivity for local shipbuilding in Bangladesh. The analysis also focuses on existing access to the resources like materials, knowledge and capital which are equally important factors for the expansion of shipbuilding. Comparison of these parameters with other nations have been made qualitatively and quantitatively to find the level of our shipbuilding. On the basis of existing condition and future vision, some recommendations have been made which might be useful for accelerating the development of this sector.展开更多
The China state shipbuilding corporation (CSSC), a leading shipbuilding enterprise of the Chinese shipbuilding industry, has made rapid progress during recent years. The welding technology, considered as the crucial f...The China state shipbuilding corporation (CSSC), a leading shipbuilding enterprise of the Chinese shipbuilding industry, has made rapid progress during recent years. The welding technology, considered as the crucial factor in the development of the industry, plays a significant role. This paper presents the growth of shipbuilding technology, the associated welding processes and the prospects for the shipbuilding industry.展开更多
Submerged arc welding process has been simulated to investigate the molten pool features of EH36 shipbuilding steel.One case only involved the surface tension model,and another one involved both the surface tension mo...Submerged arc welding process has been simulated to investigate the molten pool features of EH36 shipbuilding steel.One case only involved the surface tension model,and another one involved both the surface tension model and the interface tension model.The role of interface tension during welding is revealed,and the evolution of molten pool morphology is understood by comparing the surface temperature distribution,surface tension and interface tension distribution,and the streamline of the molten pool for the two cases.When the interface tension model is disregarded,a flow conducive to the outward expansion is formed in the surface area of the molten pool,resulting in a small weld depth-to-width ratio.After applying the interface tension model,the expanding outward flow is restrained,which leads to a deep penetration morphology with a large weld depth-to-width ratio due to the inward flow governed by the Marangoni forces.The simulation results involving the interface tension model have been verified with satisfactory predictability.展开更多
Shipbuilding is becoming more complex and requires many different enterprises and plants to work cooperatively to strive for the maximum profit.Supported by the computer technology,information technology,and internet ...Shipbuilding is becoming more complex and requires many different enterprises and plants to work cooperatively to strive for the maximum profit.Supported by the computer technology,information technology,and internet technology etc.,CSCW(Computer Supported Cooperative Work)plays a very crucial role in the multi-team,multi-subject,multi-layer field.According to shipbuilding characters and market requirements,the computer supported cooperative shipbuilding technology is re-searched actually.Key technologies to realize it are analyzed,and construction of the computer supported cooperative manufactur-ing environment is deeply discussed.On the base of them,scheme of the computer supported cooperative shipbuilding system based on PDM(Product Data Management)is put forward,which is useful to improve and develop the shipbuilding industry.展开更多
The research study proposes to examine a three-dimensional visualization program, emphasizing on improving genetic algorithms through the optimization of a layout design-based standard and discrete shipbuilding worksh...The research study proposes to examine a three-dimensional visualization program, emphasizing on improving genetic algorithms through the optimization of a layout design-based standard and discrete shipbuilding workshop. By utilizing a steel processing workshop as an example, the principle of minimum logistic costs will be implemented to obtain an ideological equipment layout, and a mathematical model. The objectiveness is to minimize the total necessary distance traveled between machines. An improved control operator is implemented to improve the iterative efficiency of the genetic algorithm, and yield relevant parameters. The Computer Aided Tri-Dimensional Interface Application （CATIA） software is applied to establish the manufacturing resource base and parametric model of the steel processing workshop. Based on the results of optimized planar logistics, a visual parametric model of the steel processing workshop is constructed, and qualitative and quantitative adjustments then are applied to the model. The method for evaluating the results of the layout is subsequently established through the utilization of AHP. In order to provide a mode of reference to the optimization and layout of the digitalized production workshop, the optimized discrete production workshop will possess a certain level of practical significance.展开更多
In the Song dynasty,when a high premium was placed on the development of foreign trade by sea,the undertakings of shipbuilding and navigation thrived to an unprecedented degree.According to archaeological discoveries,...In the Song dynasty,when a high premium was placed on the development of foreign trade by sea,the undertakings of shipbuilding and navigation thrived to an unprecedented degree.According to archaeological discoveries,multiple important breakthroughs were attained in shipbuilding technology at that time.First,watertight bulkheads became structurally improved and technologically mature.Second,there were various ways to joint multiple planks and different parts of a keel,embodying highly refined woodworking craftsmanship.Thirdly,bilge keels were in use,as were axial rudders that could move up or down,wood-and-stone anchors,and iron anchors.These technologies endowed such ship forms as the Fujian ship(Fuchuan福船)with excellent capabilities,bringing Chinese shipbuilding technologies to a peak in the Song dynasty.展开更多
文摘China’s shipbuilding industry maintained the world’s largest market share in terms of three major indicators for the 16th consecutive year in 2025,according to data released by the Ministry of Industry and Information Technology on 1 February.
文摘This review article provides a comprehensive analysis of nesting optimization algorithms in the shipbuilding industry,emphasizing their role in improving material utilization,minimizing waste,and enhancing production efficiency.The shipbuilding process involves the complex cutting and arrangement of steel plates,making the optimization of these operations vital for cost-effectiveness and sustainability.Nesting algorithms are broadly classified into four categories:exact,heuristic,metaheuristic,and hybrid.Exact algorithms ensure optimal solutions but are computationally demanding.In contrast,heuristic algorithms deliver quicker results using practical rules,although they may not consistently achieve optimal outcomes.Metaheuristic algorithms combine multiple heuristics to effectively explore solution spaces,striking a balance between solution quality and computational efficiency.Hybrid algorithms integrate the strengths of different approaches to further enhance performance.This review systematically assesses these algorithms using criteria such as material dimensions,part geometry,component layout,and computational efficiency.The findings highlight the significant potential of advanced nesting techniques to improve material utilization,reduce production costs,and promote sustainable practices in shipbuilding.By adopting suitable nesting solutions,shipbuilders can achieve greater efficiency,optimized resource management,and superior overall performance.Future research directions should focus on integrating machine learning and real-time adaptability to further enhance nesting algorithms,paving the way for smarter,more sustainable manufacturing practices in the shipbuilding industry.
基金support from the National Natural Science Foundation of China(Grant Nos.U20A20277 and 52350610226)National Key Research and Development Plan of China(Grant No.2022YFE0123300).
文摘Microstructural evolution features have been systematically investigated for the weld metal of EH36 shipbuilding steel under an in situ confocal scanning laser microscope.The influence of cooling rate on microstructural changes during the transformation from austenite to ferrite has been clarified.It is found that ferrite side plates form preceding to acicular ferrites,although the starting temperature of respective component decreases as the cooling rate is raised.In particular,the growth rate of acicular ferrite is measured to increase significantly,rising from 30.4μm/s at a cooling rate of 3 K/s to 109.0μm/s at 15 K/s,driven primarily by an ever-increasing degree of undercooling.These findings highlight the critical role of cooling rate in dictating the sequence and growth rate of microstructural transformations,which is crucial for optimizing welding processes to obtain desired microstructures while avoiding the formation of deleterious components.
基金The National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2006BAH02A06)
文摘Shipbuilding production management and logistics control are studied so as to find an advanced shipbuilding production logistics management style.The necessity and feasibility to integrate MRP-Ⅱ(manufacture resource planning)and JIT(just-in-time)are researched properly following the comparison of MRP-Ⅱ and JIT and the analysis of shipbuilding production characteristics.A shipbuilding logistics system combining MRP-Ⅱ with JIT is set up and discussed according to a master production schedule(MPS),MRP and workshop-floor production control.The system is able to simplify the shipbuilding production plan,balance the workshop production,stabilize the supply,and inspire positivity and creativity so as to raise the shipbuilding production management level.
文摘"China’s shipbuilding industry has boomed in the last 15 years since the end of the 1970s and has drawn attention of international shipbuilding and shipping circles even though a gap still remained between China and advanced shipbuilding countries including Japan and South Korea. China ranks among advanced shipbuilding countries relying on its own investment and enterprise development. China has opened its shipbuilding industry to the outside world for wider cooperation and more foreign involvement."
文摘The inclusions evolution behavior in the continuous casting slab, rolled plates, and simulated welding samples of EH36 steels with and without Zr addition has been systematically investigated. The inclusions in plain EH36 steel are almost composed of Al-Ca-S-O（-Mn） and undergo negligible changes during the whole process. With Zr addition, a large amount of individually fine MnS precipitates and Zr-containing inclusions are generated. In the rolled EH36-Zr sample, Zr-containing complex inclusions are effective to promote the nucleation of acicular ferrite on the surface, which are hardly found in the simulated welding sample of EH36-Zr steel due to the segregation of soluble Ti and Zr on the grain boundary.
基金the National Natural Science Foundation of China(Grant Nos.U20A20277,51861130361,51861145312,51850410522,5201101443,and 52011530180)the Newton Advanced Fellowship by Royal Society(Grant No.RP12G0414)+5 种基金the Royal Academy of Engineering(No.TSPC1070)the Special Fund for Key Program of Science and Technology of Liaoning Province(Grant No.2019JH1/101000014)the Research Fund for Central Universities(Grant Nos.N172502004 and N2025025)the Xingliao Talents Program(Nos.XLYC1807024 and XLYC1802024)the Regional Innovation Joint Fund of Liaoning Province(No.2020-YKLH-39)funded in part by the National Research Foundation of South Africa(No.BRICS171211293679)。
文摘Heterogeneous microstructure-induced mechanical responses in EH420 shipbuilding steel welded joint by electro-gas welding processed have been systematically studied by scanning electron microscopy,electron backscatter diffraction and mechanical testing.Comparing with the coarse-grained heat-affected zone(CGHAZ),the weld metal presents higher toughness(129.3 J vs.37.3 J)as it contains a large number of acicular ferrites with high-angle grain boundaries(frequency 79.2%)and special grain boundary∑3(frequency 55.3%).Moreover,coarse austenite grains in CGHAZ and slender martensite–austenite constituents between bainite laths may likely facilitate crack propagation.Polygonal ferrites and tempered pearlites formed at the junction of the fine-grained heat-affected zone and the intercritical heat-affected zone induced a softened zone with an average hardness of 185 HV0.5,which is the main reason for the occurrence of tensile fracture.
文摘The 6-DOF manipulator provides a new option for traditional shipbuilding for its advantages of vast working space,low power consumption,and excellent flexibility.However,the rotation of the end effector along the tool axis is functionally redundant when using a robotic arm for five-axis machining.In the process of ship construction,the performance of the parts’protective coating needs to bemachined tomeet the Performance Standard of Protective Coatings(PSPC).The arbitrary redundancy configuration in path planning will result in drastic fluctuations in the robot joint angle,greatly reducing machining quality and efficiency.There have been some studies on singleobjective optimization of redundant variables,However,the quality and efficiency of milling are not affected by a single factor,it is usually influenced by several factors,such as the manipulator stiffness,the joint motion smoothness,and the energy consumption.To solve this problem,this paper proposed a new path optimization method for the industrial robot when it is used for five-axis machining.The path smoothness performance index and the energy consumption index are established based on the joint acceleration and the joint velocity,respectively.The path planning issue is formulated as a constrained multi-objective optimization problem by taking into account the constraints of joint limits and singularity avoidance.Then,the path is split into multiple segments for optimization to avoid the slow convergence rate caused by the high dimension.An algorithm combining the non-dominated sorting genetic algorithm(NSGA-II)and the differential evolution(DE)algorithm is employed to solve the above optimization problem.The simulations validate the effectiveness of the algorithm,showing the improvement of smoothness and the reduction of energy consumption.
文摘Recently,there have been the increase of ship size and the development of oil and gas in arctic region.These trends have led to the requirements such as high strength,good toughness at low temperature and good weldability.The high performance structural steels for shipbuilding and arctic offshore structure have been developed by our own micro-alloying and TMCP technologies.M-A constituent was precisely controlled in the both HAZ and base metal to get high toughness at low temperature.Also,the grain growth of austenite at HAZ was effectively suppressed by thermally stable TiN particles,leading to a good HAZ toughness.On the other hand,there has been the key issue of crack arrestability in large size container ship.The effect of joint design on crack arrestability was investigated to prevent a catastrophic failure along the block joint of hatch side coaming.A brittle crack arrest technique was developed without block joint shift,using an arrest weld in the end of hatch side coaming weld line.
文摘To manage the complexities of hull module partitions, a new approach to the partitions of hierarchical modules for shipbuilding is proposed. Based on the assembly and manufacture process, the approach determines the hierarchy and basis of the module partition first, and then according to the type of connection between the parts of the block module, the degree of membership for the rational connection is gained and the fuzzy relation matrix between different parts is then established. The fuzzy clustering technique is used to partition the modules, and then the method of fuzzy comprehensive assessment is used to choose a relative reasonable scheme. A case study has been conducted, which proves that the approach is feasible and applicable; Especially it obtains the sub-module partition, which sets up the shipbuilding process at a higher-level assembly and has offered effective tools for the modular ship design.
基金supported by the Open Project Program of Bejing Key Laboratory of Pipeline Critical Technology and Equipment forDeepwater Oil&Gas Development(Grant No.BIPT2019001)the Natural Science Foundation of Hebei Province(Grant No.E2021318004)。
文摘The effects of Ca treatment on the particle, microstructure, and toughness of heat-affected zone (HAZ) of shipbuilding steel with Zr-Ti deoxidation after high-heat-input welding were investigated. The simulated welding at a high-heat-input welding of 200 kJ/cm was carried out using Gleeble-3800 welding simulation. Then, particle characteristics were characterized using an Aztec-Feature automatic particle analysis system. Additionally, an in-situ observation experiment was performed to study the relationships between particle and microstructure by high-temperature confocal laser scanning microscopy (HT-CLSM). The results indicated that the average HAZ toughness at -40 ℃ was increased from 183 to 290 J by adding 0.0026 wt.% Ca. Meanwhile, the formation of acicular ferrite ratio was increased from 49.34% to 60.28% due to the addition of Ca. The scanning electron microscopy results clearly showed that CaO-Al_(2)O_(3)-TiOx-ZrO_(2)-MnS particles could act as effective nucleation sites for the formation of acicular ferrite, which has been verified by the observation of the particle-microstructure relationship under HT-CLSM. Furthermore, particle characterization results show that the cumulative frequency of particles with the size of 1-3 lm was 33.2% in HAZ of Zr-Ti shipbuilding steel but 66.2% in HAZ of Zr-Ti-Ca shipbuilding steel.
基金supported by “The World Academy of Sciences,Italy(TWAS)” under the Visiting Researchers Program of TWASUNESCO Associateship Scheme(Ref.3240260896)
文摘The stretch formability of a low carbon steel processed by friction stir processing （FSP） was studied under biaxial loading condition applied by a miniaturized Erichsen test. One-pass FSP decreased the ferritic grain size in the processed zone from 25 μm to about 3 μm, which also caused a remarkable increase in strength values without considerable decrease in formability under uniaxial loading. A coarse-grained （CG） sample before FSP reflected a moderate formability with an Erichsen index （EI） of 2.73 mm. FSP slightly decreased the stretch formability of the sample to 2.66 ram. However, FSP increased the required punch load （FEI） due to the increased strength by grain refinement. FSP reduced considerably the roughness of the free surface of the biaxial stretched samples with reduced orange peel effect. The average roughness value （Ra） decreased from 2.90 in the CG sample down to about 0.65 μm in fine-grained （FG） sample after FSP. It can be concluded that the FG microstructure in low carbon steels sheets or plates used generally in shipbuilding provides a good balance between strength and formability.
文摘This article explored existing policies (if any) and current management structure which govern operations within the yard, examine some major challenges facing the ship maintenance and repair services in Tema </span><span style="font-family:Verdana;">Drydock</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">and Shipbuilding Yard, </span><span style="font-family:Verdana;">Ghana, identif</span><span style="font-family:Verdana;">ied</span><span style="font-family:Verdana;"> few drivers that impact positively on the ship repair market with particular reference to the Tema Shipyard. It concludes by proposing sustainable management and maintenance strategies for improved repair services of the yard as well as analyzing the findings obtained in the data presentation and discussion sections during the research project. The main finding is that the PSC Tema Shipyard’s ship maintenance and repair services are really overwhelmed with major challenges, representing 55% after summing up four (4) out of the seven (7) captured in the study and are threatening its sustainability, if not properly researched and addressed once and for all. As already stated, carefully analysed conclusion</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> w</span><span style="font-family:Verdana;">ere</span><span style="font-family:Verdana;"> drawn to effectively address these challenges, followed by suggestions for future research to forestall its cascading effects on the Ghanaian economy as a </span><span style="font-family:Verdana;">whole.
文摘Shipbuilding in Bangladesh has been considered as the most promising industry in the recent time and the country is dreaming to emerge as a middle income country within a short time by maintaining the upward trend of this sector. However, due to global nature and the long term sustainability of this shipbuilding industry, an investigation of competitiveness in terms of global standard is of prime importance. This paper focuses on studying some crucial competitive factors like labor skill, labor availability, labor man-hour, labor cost ＆ productivity for local shipbuilding in Bangladesh. The analysis also focuses on existing access to the resources like materials, knowledge and capital which are equally important factors for the expansion of shipbuilding. Comparison of these parameters with other nations have been made qualitatively and quantitatively to find the level of our shipbuilding. On the basis of existing condition and future vision, some recommendations have been made which might be useful for accelerating the development of this sector.
文摘The China state shipbuilding corporation (CSSC), a leading shipbuilding enterprise of the Chinese shipbuilding industry, has made rapid progress during recent years. The welding technology, considered as the crucial factor in the development of the industry, plays a significant role. This paper presents the growth of shipbuilding technology, the associated welding processes and the prospects for the shipbuilding industry.
基金The authors sincerely thank the National Natural Science Foundation of China(Grant Nos.U20A20277,52150610494,52104295,52011530180 and 52050410341)Research Fund for Central Universities(Grant Nos.N2125016 and N2025025)Young Elite Scientists Sponsorship Program by CAST(YESS)(Grant No.2021-2023QNRC001).
文摘Submerged arc welding process has been simulated to investigate the molten pool features of EH36 shipbuilding steel.One case only involved the surface tension model,and another one involved both the surface tension model and the interface tension model.The role of interface tension during welding is revealed,and the evolution of molten pool morphology is understood by comparing the surface temperature distribution,surface tension and interface tension distribution,and the streamline of the molten pool for the two cases.When the interface tension model is disregarded,a flow conducive to the outward expansion is formed in the surface area of the molten pool,resulting in a small weld depth-to-width ratio.After applying the interface tension model,the expanding outward flow is restrained,which leads to a deep penetration morphology with a large weld depth-to-width ratio due to the inward flow governed by the Marangoni forces.The simulation results involving the interface tension model have been verified with satisfactory predictability.
文摘Shipbuilding is becoming more complex and requires many different enterprises and plants to work cooperatively to strive for the maximum profit.Supported by the computer technology,information technology,and internet technology etc.,CSCW(Computer Supported Cooperative Work)plays a very crucial role in the multi-team,multi-subject,multi-layer field.According to shipbuilding characters and market requirements,the computer supported cooperative shipbuilding technology is re-searched actually.Key technologies to realize it are analyzed,and construction of the computer supported cooperative manufactur-ing environment is deeply discussed.On the base of them,scheme of the computer supported cooperative shipbuilding system based on PDM(Product Data Management)is put forward,which is useful to improve and develop the shipbuilding industry.
文摘The research study proposes to examine a three-dimensional visualization program, emphasizing on improving genetic algorithms through the optimization of a layout design-based standard and discrete shipbuilding workshop. By utilizing a steel processing workshop as an example, the principle of minimum logistic costs will be implemented to obtain an ideological equipment layout, and a mathematical model. The objectiveness is to minimize the total necessary distance traveled between machines. An improved control operator is implemented to improve the iterative efficiency of the genetic algorithm, and yield relevant parameters. The Computer Aided Tri-Dimensional Interface Application （CATIA） software is applied to establish the manufacturing resource base and parametric model of the steel processing workshop. Based on the results of optimized planar logistics, a visual parametric model of the steel processing workshop is constructed, and qualitative and quantitative adjustments then are applied to the model. The method for evaluating the results of the layout is subsequently established through the utilization of AHP. In order to provide a mode of reference to the optimization and layout of the digitalized production workshop, the optimized discrete production workshop will possess a certain level of practical significance.
基金Funded by the National Key Research and Development Program of China[2020YFC1521805]the result of the subproject“Research on Structural Stability and Protection Technologies for Wooden Marine Shipwrecks”(海洋出水木质沉船结构稳定性与保护技术研究)of the project“Research and Development of Key Technologies for Protection of Wooden Marine Cultural Relics”(海洋出水木质文物保护关键技术研发)under the special project“Monitoring,Early Warning,and Prevention of Major Natural Disasters”(重大自然灾害监测预警与防范)
文摘In the Song dynasty,when a high premium was placed on the development of foreign trade by sea,the undertakings of shipbuilding and navigation thrived to an unprecedented degree.According to archaeological discoveries,multiple important breakthroughs were attained in shipbuilding technology at that time.First,watertight bulkheads became structurally improved and technologically mature.Second,there were various ways to joint multiple planks and different parts of a keel,embodying highly refined woodworking craftsmanship.Thirdly,bilge keels were in use,as were axial rudders that could move up or down,wood-and-stone anchors,and iron anchors.These technologies endowed such ship forms as the Fujian ship(Fuchuan福船)with excellent capabilities,bringing Chinese shipbuilding technologies to a peak in the Song dynasty.
