The constant panel method within the framework of potential flow theory in the time domain is developed for solving the hydrodynamic interactions between two parallel ships with forward speed.When solving problems wit...The constant panel method within the framework of potential flow theory in the time domain is developed for solving the hydrodynamic interactions between two parallel ships with forward speed.When solving problems within a time domain framework,the free water surface needs to simultaneously satisfy both the kinematic and dynamic boundary conditions of the free water surface.This provides conditions for adding artificial damping layers.Using the Runge−Kutta method to solve equations related to time.An upwind differential scheme is used in the present method to deal with the convection terms on the free surface to prevent waves upstream.Through the comparison with the available experimental data and other numerical methods,the present method is proved to have good mesh convergence,and satisfactory results can be obtained.The constant panel method is applied to calculate the hydrodynamic interaction responses of two parallel ships advancing in head waves.Numerical simulations are conducted on the effects of forward speed,different longitudinal and lateral distances on the motion response of two modified Wigley ships in head waves.Then further investigations are conducted on the effects of different ship types on the motion response.展开更多
In a general case, container ship serves many different ports on each voyage. A stowage planning for container ship made at one port must take account of the influence on subsequent ports. So the complexity of stowage...In a general case, container ship serves many different ports on each voyage. A stowage planning for container ship made at one port must take account of the influence on subsequent ports. So the complexity of stowage planning problem increases due to its multi-ports nature. This problem is NP-hard problem. In order to reduce the computational complexity, the problem is decomposed into two sub-problems in this paper. First, container ship stowage problem (CSSP) is regarded as 'packing problem', ship-bays on the board of vessel are regarded as bins, the number of slots at each bay are taken as capacities of bins, and containers with different characteristics (homogeneous containers group) are treated as items packed. At this stage, there are two objective functions, one is to minimize the number of bays packed by containers and the other is to minimize the number of overstows. Secondly, containers assigned to each bays at first stage are allocate to special slot, the objective functions are to minimize the metacentric height, heel and overstows.The taboo search heuristics algorithm are used to solve the subproblem. The main focus of this paper is on the first subproblem. A case certifies the feasibility of the model and algorithm.展开更多
Containership stowage plans are a pivotal teaches in the system of container transportation.With the increasing containers shipping,planning containership stowage has become more and more complicated.So intelligent st...Containership stowage plans are a pivotal teaches in the system of container transportation.With the increasing containers shipping,planning containership stowage has become more and more complicated.So intelligent stowage planning for containerships is of great significance.An effective stowage plan may improve efficiency of transportation system.First,the progress of containership stowage plan at home and abroad is reviewed,including the latest developments,such as the application of various optimization methods and computer techniques to the problem.Then,the complexities of the problem are discussed and areas where investigations are still needed are pointed out.This will provide a reference for further research on the subject.展开更多
The International Maritime Organization (IMO) has encouraged its member countries to introduce Formal Safety Assessment (FSA) for ship operations since the end of the last century. FSA can be used through certain form...The International Maritime Organization (IMO) has encouraged its member countries to introduce Formal Safety Assessment (FSA) for ship operations since the end of the last century. FSA can be used through certain formal assessing steps to generate effective recommendations and cautions to control marine risks and improve the safety of ships. On the basis of the brief introduction of FSA, this paper describes the ideas of applying FSA to the prevention of human error in ship operations. It especially discusses the investigation and analysis of the information and data using navigation simulators and puts forward some suggestions for the introduction and development of the FSA research work for safer ship operations.展开更多
The modeling of a ship steering integrated simulator(SSIS)applied to the design,debugging and maintenance of an autopilot is discussed.A nonlinear responsive model is proposed and applied to the design of SSIS.The SSI...The modeling of a ship steering integrated simulator(SSIS)applied to the design,debugging and maintenance of an autopilot is discussed.A nonlinear responsive model is proposed and applied to the design of SSIS.The SSIS generates real signals of the ship heading,the rudder angle,the ship position and the output to the autopilot.A variety of factors,such as ship speed variety,shallow water effect,nonlinearity of yaw and actuator,and environmental disturbances like wind,wave and current are considered carefully.Detailed formulas for calculating relevant parameters are provided.Taken a naval ship as an example,the physical-digital simulations on SSIS and the digital simulation on a Marine System Simulator(MSS)were conducted separately in various sailing conditions.Simulation results show that the simple nonlinear responsive model can be applied to ship motion control and simulation with sufficient accuracy and effectiveness.展开更多
Ice resistance prediction is a critical issue in the preliminary design of ships navigating brash ice conditions, which is closely related to the safety of a ship to navigate encounter brash ice, and has significant e...Ice resistance prediction is a critical issue in the preliminary design of ships navigating brash ice conditions, which is closely related to the safety of a ship to navigate encounter brash ice, and has significant effects on the kinds of propellers and motor power needed. In research on this topic, model tests and full-scale tests on ships have thus far been the primary approaches. In recent years, the application of the finite element method(FEM) has also attracted interest. Some researchers have conducted numerical simulations on ship–ice interactions using the fluid–structure interaction(FSI) method. This study used this method to predict and analyze the resistance of an ice-going ship, and compared the results with those of model ship tests conducted in a towing tank with synthetic ice to discuss the feasibility of the FEM. A numerical simulation and experimental methods were used to predict the brash ice resistance of an ice-going container ship model in a condition with three concentrations of brash ice(60%, 80%, and 90%). A comparison of the results yielded satisfactory agreement between the numerical simulation and the experiments in terms of both observed phenomena and resistance values, indicating that the proposed numerical simulation has significant potential for use in related studies in the future.展开更多
As the maneuverability of a ship navigating close to a bank is influenced by the sidewall, the assessment of ship maneuvering stability is important. The hydrodynamic derivatives measured by the planar motion mechani...As the maneuverability of a ship navigating close to a bank is influenced by the sidewall, the assessment of ship maneuvering stability is important. The hydrodynamic derivatives measured by the planar motion mechanism (PMM) test provide a way to predict the change of ship maneuverability. This paper presents a numerical simulation of PMM model tests with variant distances to a vertical bank by using unsteady RANS equations. A hybrid dynamic mesh technique is developed to realize the mesh configuration and remeshing of dynamic PMM tests when the ship is close to the bank. The proposed method is validated by comparing numerical results with results of PMM tests in a circulating water channel. The first-order hydrodynamic derivatives of the ship are analyzed from the time history of lateral force and yaw moment according to the multiple-run simulating procedure and the variations of hydrodynamic derivatives with the ship-sidewall distance are given. The straight line stability and directional stability are also discussed and stable or unstable zone of proportional-derivative (PD) controller parameters for directional stability is shown, which can be a reference for course keeping operation when sailing near a bank.展开更多
In this paper,we present a numerical simulation method of electromagnetic(EM)fields induced by a moving ship(EMFMS),which consist of both the shaft-rate EM field and the static EM field.The shaft-rate EM fields in the...In this paper,we present a numerical simulation method of electromagnetic(EM)fields induced by a moving ship(EMFMS),which consist of both the shaft-rate EM field and the static EM field.The shaft-rate EM fields in the frequency domain are first obtained by solving the partial differential equations together with suitable boundary conditions,and then they are transformed into the time domain by using the inverse Fourier transform.Finally,the static fields are added to obtain the EM fields of a moving ship.The effects of the source current intensity and the source position on the EM fields of a moving ship are discussed in detail.A field example of EM response of a moving ship is presented and its characteristics are analyzed.展开更多
In this paper a 3-D panoramic simulation system of a ship is described which is developed with the MAXSCRIPT language and VC++ as programming tools on the platform of 3Dsmax. The strip theory method is applied to the ...In this paper a 3-D panoramic simulation system of a ship is described which is developed with the MAXSCRIPT language and VC++ as programming tools on the platform of 3Dsmax. The strip theory method is applied to the motion prediction of the mono-hull. The time history solutions of heave and pitch are obtained in the condition of head sea to provide the primary data on panoramic simulation. The simulation system has following functions: 1)digital simulation;2) panoramic simulation; 3) environmental set-up; 4) render preview and output.展开更多
The max collision force of ship-bridge collision is one of the most important references for bridge design. By means of nonlinear digital simulation method, the collision forces of the collisions between rigid bridge ...The max collision force of ship-bridge collision is one of the most important references for bridge design. By means of nonlinear digital simulation method, the collision forces of the collisions between rigid bridge pier and ship bow were calculated out for four different ships, whose tonnages are 5000,10000,50000 and 60000 DWT respectively. Curves of collision force-penetration and absorbed energy-penetration are obtained, and the data of the max loads are then summarized. On the basis of these curves and data, a set of curves describing the relationships between max collision forces and tonnages of the ships are successfully presented, by which the max collision forces of the ships-bridge with different tonnages and in different velocities can be estimated easily and reliably.展开更多
The three-stage simulation method based on LS-DYNA was introduced in this study to simulate the progressive collapse of a continuous girder bridge after a ship-bridge collision. The pile-soil dynamic interaction and t...The three-stage simulation method based on LS-DYNA was introduced in this study to simulate the progressive collapse of a continuous girder bridge after a ship-bridge collision. The pile-soil dynamic interaction and the initial stress and deformation of the whole bridge before the collision were considered. By analyzing the damage, deformation, stress distribution and collapse process of the whole bridge, the results show that the displacement response of the cap beam lags behind the pile cap. The response order of the whole bridge's components depends on their distances from the collision region. The plastic deformation of soil around piles has a positive effect on delaying the further increase in the displacement of piles. The impacted pier's losing stability and its superstructure's excessive deformation are the main reasons leading to the progressive collapse of the continuous girder bridge.展开更多
Ship waves are observed with wave-generating techniques by way of simulating express liners in the Zhujiang Delta.The analog test study of ship waves is conducted in a wave flume and a wave basin respectively. Thus, d...Ship waves are observed with wave-generating techniques by way of simulating express liners in the Zhujiang Delta.The analog test study of ship waves is conducted in a wave flume and a wave basin respectively. Thus, different wave elements and different incident angles of ship waves are decided; so are different slopes of protection, the plafform, width of plafform, and the influence over the ship wave run-up on protection from armor coat structure. The empirical relation-展开更多
The head-on collision process between ship and concrete pile supported protective system is simulated by software LS-DYNA. The influences of pile non-linearity and soil non-linearity on impact force, ship crush depth ...The head-on collision process between ship and concrete pile supported protective system is simulated by software LS-DYNA. The influences of pile non-linearity and soil non-linearity on impact force, ship crush depth and the cap displacement of pile supported protective system are discussed. It's shown that for both severe impact case and non-severe impact case, the non-linearity of pile material influence the impact force history, ship crush depth. The non-linearity of pile material and soil has remarkable influence on the cap displacement especially for severe impact case. These issues should not be ignored in the analysis of pile supported protective system subjected to ship impact.展开更多
The characteristics of the design resources in the ship collaborative design is described and the hierarchical model for the evaluation of the design resources is established. The comprehensive evaluation of the co-de...The characteristics of the design resources in the ship collaborative design is described and the hierarchical model for the evaluation of the design resources is established. The comprehensive evaluation of the co-designers for the collaborative design resources has been done from different aspects using Analytic Hierarchy Process (AHP),and according to the evaluation results,the candidates are determined. Meanwhile,based on the principle of minimum cost,and starting from the relations between the design tasks and the corresponding co-designers,the optimizing selection model of the collaborators is established and one novel genetic combined with simulated annealing algorithm is proposed to realize the optimization. It overcomes the defects of the genetic algorithm which may lead to the premature convergence and local optimization if used individually. Through the application of this method in the ship collaborative design system,it proves the feasibility and provides a quantitative method for the optimizing selection of the design resources.展开更多
The transformation of parallel translation can improve the smoothness of discrete series sometimes. In this paper, for ship pitch, a method to modify the system error is proposed via the transformation of parallel tra...The transformation of parallel translation can improve the smoothness of discrete series sometimes. In this paper, for ship pitch, a method to modify the system error is proposed via the transformation of parallel translation, which can give the optimize parameters using the Method of Minimum Squares. The series in the method can fit white exponential law better, and then be applied in GM (1,1) very well. The numerical experiments imply that the method is practical, which make the ship pitch system model more accurate than GM ( 1,1 ).展开更多
Steel fenders are increasingly used for ship-impact resistance structures in the design of navigable bridges. As an important approach to investigating this anti-impact structure effectiveness to reduce influences of ...Steel fenders are increasingly used for ship-impact resistance structures in the design of navigable bridges. As an important approach to investigating this anti-impact structure effectiveness to reduce influences of vessel impact, simulation analyses are still not perfect yet. So this paper is intended to discuss several issues related to ship collision simulations, including steel constitutive relationship, connections between steel box and pile cap, contacts definition and friction consideration, and the determination of impact waterlines and angles. Consequently based on two examples of ship-steel fender-bridge structure systems, some conclusions about effectiveness and design of fenders to reduce ship impact are drawn.展开更多
Considering the effects of increased economic globalization and global warming,developing methods for reducing shipping costs and greenhouse gas emissions in ocean transportation has become crucial.Owing to its key ro...Considering the effects of increased economic globalization and global warming,developing methods for reducing shipping costs and greenhouse gas emissions in ocean transportation has become crucial.Owing to its key role in modern navigation technology,ship weather routing is the research focus of several scholars in this field.This study presents a hybrid genetic algorithm for the design of an optimal ship route for safe transoceanic navigation under complicated sea conditions.On the basis of the basic genetic algorithm,simulated annealing algorithm is introduced to enhance its local search ability and avoid premature convergence,with the ship’s voyage time and fuel consumption as optimization goals.Then,a mathematical model of ship weather routing is developed based on the grid system.A measure of fitness calibration is proposed,which can change the selection pressure of the algorithm as the population evolves.In addition,a hybrid crossover operator is proposed to enhance the ability to find the optimal solution and accelerate the convergence speed of the algorithm.Finally,a multi-population technique is applied to improve the robustness of the algorithm using different evolutionary strategies.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52271278 and 52111530137)the Natural Science Found of Jiangsu Province(Grant No.BK20221389)the Newton Advanced Fellowships(Grant No.NAF\R1\180304)by the Royal Society.
文摘The constant panel method within the framework of potential flow theory in the time domain is developed for solving the hydrodynamic interactions between two parallel ships with forward speed.When solving problems within a time domain framework,the free water surface needs to simultaneously satisfy both the kinematic and dynamic boundary conditions of the free water surface.This provides conditions for adding artificial damping layers.Using the Runge−Kutta method to solve equations related to time.An upwind differential scheme is used in the present method to deal with the convection terms on the free surface to prevent waves upstream.Through the comparison with the available experimental data and other numerical methods,the present method is proved to have good mesh convergence,and satisfactory results can be obtained.The constant panel method is applied to calculate the hydrodynamic interaction responses of two parallel ships advancing in head waves.Numerical simulations are conducted on the effects of forward speed,different longitudinal and lateral distances on the motion response of two modified Wigley ships in head waves.Then further investigations are conducted on the effects of different ship types on the motion response.
基金Supported by a Special Fund Support Item of Doctor Subject of Colleges and Universities (No. 2000014125)
文摘In a general case, container ship serves many different ports on each voyage. A stowage planning for container ship made at one port must take account of the influence on subsequent ports. So the complexity of stowage planning problem increases due to its multi-ports nature. This problem is NP-hard problem. In order to reduce the computational complexity, the problem is decomposed into two sub-problems in this paper. First, container ship stowage problem (CSSP) is regarded as 'packing problem', ship-bays on the board of vessel are regarded as bins, the number of slots at each bay are taken as capacities of bins, and containers with different characteristics (homogeneous containers group) are treated as items packed. At this stage, there are two objective functions, one is to minimize the number of bays packed by containers and the other is to minimize the number of overstows. Secondly, containers assigned to each bays at first stage are allocate to special slot, the objective functions are to minimize the metacentric height, heel and overstows.The taboo search heuristics algorithm are used to solve the subproblem. The main focus of this paper is on the first subproblem. A case certifies the feasibility of the model and algorithm.
基金Supported by High-tech Research of Educational Department of Liaoning Province (No.05L091)a Special Fund Support Item of Doctor Subject of Colleges and Universities(No.2000014125)
文摘Containership stowage plans are a pivotal teaches in the system of container transportation.With the increasing containers shipping,planning containership stowage has become more and more complicated.So intelligent stowage planning for containerships is of great significance.An effective stowage plan may improve efficiency of transportation system.First,the progress of containership stowage plan at home and abroad is reviewed,including the latest developments,such as the application of various optimization methods and computer techniques to the problem.Then,the complexities of the problem are discussed and areas where investigations are still needed are pointed out.This will provide a reference for further research on the subject.
文摘The International Maritime Organization (IMO) has encouraged its member countries to introduce Formal Safety Assessment (FSA) for ship operations since the end of the last century. FSA can be used through certain formal assessing steps to generate effective recommendations and cautions to control marine risks and improve the safety of ships. On the basis of the brief introduction of FSA, this paper describes the ideas of applying FSA to the prevention of human error in ship operations. It especially discusses the investigation and analysis of the information and data using navigation simulators and puts forward some suggestions for the introduction and development of the FSA research work for safer ship operations.
文摘The modeling of a ship steering integrated simulator(SSIS)applied to the design,debugging and maintenance of an autopilot is discussed.A nonlinear responsive model is proposed and applied to the design of SSIS.The SSIS generates real signals of the ship heading,the rudder angle,the ship position and the output to the autopilot.A variety of factors,such as ship speed variety,shallow water effect,nonlinearity of yaw and actuator,and environmental disturbances like wind,wave and current are considered carefully.Detailed formulas for calculating relevant parameters are provided.Taken a naval ship as an example,the physical-digital simulations on SSIS and the digital simulation on a Marine System Simulator(MSS)were conducted separately in various sailing conditions.Simulation results show that the simple nonlinear responsive model can be applied to ship motion control and simulation with sufficient accuracy and effectiveness.
基金financially supported by the National Natural Science Foundation of China(Grant No.51679052)the Natural Science Foundation of Heilongjiang Province of China(Grant No.E2018026)the Defense Industrial Technology Development Program(Grant No.JCKY2016604B001)
文摘Ice resistance prediction is a critical issue in the preliminary design of ships navigating brash ice conditions, which is closely related to the safety of a ship to navigate encounter brash ice, and has significant effects on the kinds of propellers and motor power needed. In research on this topic, model tests and full-scale tests on ships have thus far been the primary approaches. In recent years, the application of the finite element method(FEM) has also attracted interest. Some researchers have conducted numerical simulations on ship–ice interactions using the fluid–structure interaction(FSI) method. This study used this method to predict and analyze the resistance of an ice-going ship, and compared the results with those of model ship tests conducted in a towing tank with synthetic ice to discuss the feasibility of the FEM. A numerical simulation and experimental methods were used to predict the brash ice resistance of an ice-going container ship model in a condition with three concentrations of brash ice(60%, 80%, and 90%). A comparison of the results yielded satisfactory agreement between the numerical simulation and the experiments in terms of both observed phenomena and resistance values, indicating that the proposed numerical simulation has significant potential for use in related studies in the future.
基金supported by the National Key Basic Research Program of China(Grant No.2014CB046804)
文摘As the maneuverability of a ship navigating close to a bank is influenced by the sidewall, the assessment of ship maneuvering stability is important. The hydrodynamic derivatives measured by the planar motion mechanism (PMM) test provide a way to predict the change of ship maneuverability. This paper presents a numerical simulation of PMM model tests with variant distances to a vertical bank by using unsteady RANS equations. A hybrid dynamic mesh technique is developed to realize the mesh configuration and remeshing of dynamic PMM tests when the ship is close to the bank. The proposed method is validated by comparing numerical results with results of PMM tests in a circulating water channel. The first-order hydrodynamic derivatives of the ship are analyzed from the time history of lateral force and yaw moment according to the multiple-run simulating procedure and the variations of hydrodynamic derivatives with the ship-sidewall distance are given. The straight line stability and directional stability are also discussed and stable or unstable zone of proportional-derivative (PD) controller parameters for directional stability is shown, which can be a reference for course keeping operation when sailing near a bank.
基金This study is supported by the Fundamental Research Funds for the Central Universities(No.201861020)the Wenhai Program of Qingdao National Laboratory for Marine Science and Technology(QNLM)(No.2017WH ZZB0201).
文摘In this paper,we present a numerical simulation method of electromagnetic(EM)fields induced by a moving ship(EMFMS),which consist of both the shaft-rate EM field and the static EM field.The shaft-rate EM fields in the frequency domain are first obtained by solving the partial differential equations together with suitable boundary conditions,and then they are transformed into the time domain by using the inverse Fourier transform.Finally,the static fields are added to obtain the EM fields of a moving ship.The effects of the source current intensity and the source position on the EM fields of a moving ship are discussed in detail.A field example of EM response of a moving ship is presented and its characteristics are analyzed.
文摘In this paper a 3-D panoramic simulation system of a ship is described which is developed with the MAXSCRIPT language and VC++ as programming tools on the platform of 3Dsmax. The strip theory method is applied to the motion prediction of the mono-hull. The time history solutions of heave and pitch are obtained in the condition of head sea to provide the primary data on panoramic simulation. The simulation system has following functions: 1)digital simulation;2) panoramic simulation; 3) environmental set-up; 4) render preview and output.
文摘The max collision force of ship-bridge collision is one of the most important references for bridge design. By means of nonlinear digital simulation method, the collision forces of the collisions between rigid bridge pier and ship bow were calculated out for four different ships, whose tonnages are 5000,10000,50000 and 60000 DWT respectively. Curves of collision force-penetration and absorbed energy-penetration are obtained, and the data of the max loads are then summarized. On the basis of these curves and data, a set of curves describing the relationships between max collision forces and tonnages of the ships are successfully presented, by which the max collision forces of the ships-bridge with different tonnages and in different velocities can be estimated easily and reliably.
基金Supported by the National Natural Science Foundation of China(No.51178310)the Foundation of China Scholarship Council(No.201308120137)
文摘The three-stage simulation method based on LS-DYNA was introduced in this study to simulate the progressive collapse of a continuous girder bridge after a ship-bridge collision. The pile-soil dynamic interaction and the initial stress and deformation of the whole bridge before the collision were considered. By analyzing the damage, deformation, stress distribution and collapse process of the whole bridge, the results show that the displacement response of the cap beam lags behind the pile cap. The response order of the whole bridge's components depends on their distances from the collision region. The plastic deformation of soil around piles has a positive effect on delaying the further increase in the displacement of piles. The impacted pier's losing stability and its superstructure's excessive deformation are the main reasons leading to the progressive collapse of the continuous girder bridge.
文摘Ship waves are observed with wave-generating techniques by way of simulating express liners in the Zhujiang Delta.The analog test study of ship waves is conducted in a wave flume and a wave basin respectively. Thus, different wave elements and different incident angles of ship waves are decided; so are different slopes of protection, the plafform, width of plafform, and the influence over the ship wave run-up on protection from armor coat structure. The empirical relation-
文摘The head-on collision process between ship and concrete pile supported protective system is simulated by software LS-DYNA. The influences of pile non-linearity and soil non-linearity on impact force, ship crush depth and the cap displacement of pile supported protective system are discussed. It's shown that for both severe impact case and non-severe impact case, the non-linearity of pile material influence the impact force history, ship crush depth. The non-linearity of pile material and soil has remarkable influence on the cap displacement especially for severe impact case. These issues should not be ignored in the analysis of pile supported protective system subjected to ship impact.
文摘The characteristics of the design resources in the ship collaborative design is described and the hierarchical model for the evaluation of the design resources is established. The comprehensive evaluation of the co-designers for the collaborative design resources has been done from different aspects using Analytic Hierarchy Process (AHP),and according to the evaluation results,the candidates are determined. Meanwhile,based on the principle of minimum cost,and starting from the relations between the design tasks and the corresponding co-designers,the optimizing selection model of the collaborators is established and one novel genetic combined with simulated annealing algorithm is proposed to realize the optimization. It overcomes the defects of the genetic algorithm which may lead to the premature convergence and local optimization if used individually. Through the application of this method in the ship collaborative design system,it proves the feasibility and provides a quantitative method for the optimizing selection of the design resources.
文摘The transformation of parallel translation can improve the smoothness of discrete series sometimes. In this paper, for ship pitch, a method to modify the system error is proposed via the transformation of parallel translation, which can give the optimize parameters using the Method of Minimum Squares. The series in the method can fit white exponential law better, and then be applied in GM (1,1) very well. The numerical experiments imply that the method is practical, which make the ship pitch system model more accurate than GM ( 1,1 ).
文摘Steel fenders are increasingly used for ship-impact resistance structures in the design of navigable bridges. As an important approach to investigating this anti-impact structure effectiveness to reduce influences of vessel impact, simulation analyses are still not perfect yet. So this paper is intended to discuss several issues related to ship collision simulations, including steel constitutive relationship, connections between steel box and pile cap, contacts definition and friction consideration, and the determination of impact waterlines and angles. Consequently based on two examples of ship-steel fender-bridge structure systems, some conclusions about effectiveness and design of fenders to reduce ship impact are drawn.
基金funded by the Russian Foundation for Basic Research(RFBR)(No.20-07-00531).
文摘Considering the effects of increased economic globalization and global warming,developing methods for reducing shipping costs and greenhouse gas emissions in ocean transportation has become crucial.Owing to its key role in modern navigation technology,ship weather routing is the research focus of several scholars in this field.This study presents a hybrid genetic algorithm for the design of an optimal ship route for safe transoceanic navigation under complicated sea conditions.On the basis of the basic genetic algorithm,simulated annealing algorithm is introduced to enhance its local search ability and avoid premature convergence,with the ship’s voyage time and fuel consumption as optimization goals.Then,a mathematical model of ship weather routing is developed based on the grid system.A measure of fitness calibration is proposed,which can change the selection pressure of the algorithm as the population evolves.In addition,a hybrid crossover operator is proposed to enhance the ability to find the optimal solution and accelerate the convergence speed of the algorithm.Finally,a multi-population technique is applied to improve the robustness of the algorithm using different evolutionary strategies.