Ship main size type selection design method, medium and terminal

Abstract

The invention provides a ship main size type selection design method, a medium and a terminal. The method comprises the steps of establishing a design variable based on a ship main size; establishing a ship type evaluation index and constraint function database; constructing an objective function of the evaluation indexes; introducing a genetic evolutionary algorithm to solve the objective function and obtain an optimal solution set database; and establishing a market model based on the optimal solution set, and calculating a maximum value of the market model to determine an optimal design variable. Through the method, the iterative calculation time of ship main scale type selection can be effectively shortened.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding design, and in particular to a method, medium, and terminal for selecting and designing main dimensions of a ship. Background Technology

[0002] For newly developed ship types, there is no single optimal or mainstream solution for selecting principal dimensions. In modern ship development, principal dimension selection is actually a multi-objective optimization and multi-attribute decision-making problem. For example, in the early stages of ship design, the selection of principal dimension parameters is complex and involves many interrelated factors. Parameters such as length, beam, depth, and draft can conflict when selected. Generally, a better length-to-beam ratio often leads to better ship performance but also significantly increases construction costs; ships with a larger block coefficient have a larger cargo capacity but often suffer from lower speed; increasing the beam often greatly improves stability but negatively impacts maneuverability. Therefore, the efficiency of principal dimension selection is relatively low. Summary of the Invention

[0003] In view of the shortcomings of the above-mentioned related technologies, the purpose of this invention is to provide a ship main dimension selection design method, medium and terminal to solve the problem of low efficiency in ship main dimension selection in the related technologies.

[0004] To achieve the above and other related objectives, the present invention provides a method for selecting and designing the main dimensions of a ship, comprising:

[0005] Design variables are established based on the ship's main dimensions;

[0006] Establish a database of ship type evaluation indicators and constraint functions;

[0007] Construct the objective function for the evaluation indicators;

[0008] A genetic evolutionary algorithm is introduced to solve the objective function and obtain an optimal solution set database.

[0009] A market model is established based on the optimal solution set, and the maximum value of the market model is calculated to determine the optimal design variables.

[0010] Optionally, the main dimensions of the vessel include length, beam, draft, block coefficient, and depth.

[0011] Optionally, the evaluation indicators include deadweight, speed, fuel consumption, cargo capacity, deadweight utilization rate, naval constant, cargo capacity utilization rate, fuel consumption per ton-nautical mile, and total tonnage to deadweight ratio.

[0012] Optionally, the constraint function database includes speed performance constraint functions and stability performance constraint functions.

[0013] Optionally, the constraint function database also includes restrictions on the maximum permissible cargo hold capacity, length, beam, maximum draft, and air draft of ships at global ethane receiving terminals and ethane export terminals, as well as ship specification requirements.

[0014] Optionally, the market model includes a revenue model and a cost model. An impact factor 'a' is set for the revenue model, and an impact factor 'b' is set for the cost model. The market model = revenue model × a - cost model × b.

[0015] A storage medium, characterized in that: the storage medium stores a computer program, which, when executed by a processor, implements the ship master size selection design method as described above.

[0016] A terminal, characterized in that: the terminal includes a processor and a memory; the memory is used to store computer programs; the processor is connected to the memory and is used to execute the computer programs stored in the memory, so that the terminal performs the ship master size selection design method as described above.

[0017] As described above, the ship main dimension selection design method, medium and terminal of the present invention have the following beneficial effects: In view of the main dimension selection problem in the ship type design stage, the present invention constructs a unified evaluation system. By establishing a ship type technical evaluation model and a market evaluation model, the overall performance of the ship and the overall market benefits can be comprehensively considered in the early stage of research and development, which can effectively reduce the iterative calculation time for ship main dimension selection. Attached Figure Description

[0018] Figure 1 The diagram shown is a flowchart illustrating the ship main size selection and design method in an embodiment of the present invention.

[0019] Figure 2 The diagram shows a flowchart of the genetic algorithm in an embodiment of the present invention. Detailed Implementation

[0020] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0021] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0022] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for the device in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or there may be one or more layers in between. The phrase “between” as used herein includes both endpoint values.

[0023] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0024] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0025] like Figure 1 As shown in the figure, this embodiment provides a method for selecting and designing the main dimensions of a ship, and the specific steps include:

[0026] Design variables are established based on the ship's main dimensions.

[0027] Specifically, the main dimensions of a ship include its length, beam, draft, block coefficient, and depth, which can be represented by X1-X5 respectively.

[0028] Establish ship type evaluation indicators.

[0029] Specifically, the evaluation indicators include deadweight, speed, fuel consumption, cargo capacity, deadweight utilization rate, naval constant, cargo capacity utilization rate, fuel consumption per ton-nautical mile, and gross tonnage to deadweight ratio. These indicators are used to represent the main performance characteristics of a ship.

[0030] Based on a pre-defined ship type database, an objective function for the evaluation index is constructed, and the objective function is selected as either maximum or minimum. The independent variable of the evaluation index function is the set design variable, and the dependent variable of the evaluation index function is the set evaluation index.

[0031] For example, the objective function for speed is defined as:

[0032]

[0033] Among them, P s To set the host power.

[0034] The objective function for the load capacity is defined as: P2 = X1·X2·X3·X4 - 0.0948·X1·X2·X5.

[0035] The objective function for load capacity utilization is defined as follows:

[0036]

[0037] Establish a constraint function database.

[0038] Specifically, the database includes: defining a speed performance constraint function, expressed as: S1 = X1 / X2. According to the pool database, 6 < X1 / X2 < 8. A large ratio indicates a slender hull, resulting in good speed and heading stability, but poor turning ability.

[0039] The stability performance constraint function is defined as: S2 = X2 / X3. According to the pool database, 2 < X1 / X2 < 4. A larger ratio indicates a larger hull width and better ship stability. However, it also indicates a smaller rolling period, more severe rolling, and greater sailing resistance.

[0040] Global ethane receiving and export terminals impose restrictions on the maximum permissible cargo hold capacity, ship length, beam, maximum draft, and air draft of vessels. For example, a constraint function is constructed based on terminal compatibility requirements: X1 < 274, X2 < 42, X3 < 11.9, 0.72 < X4 < 0.8.

[0041] The wind, wave, and current load information and structural load requirements of global operating routes limit the performance of ship parameters such as roll and wave riding, thereby constraining the high values ​​of initial stability and center of gravity of the ship under full load and ballast conditions.

[0042] Ship specifications and requirements.

[0043] The NSGA genetic evolution algorithm is introduced to solve the objective function and obtain the optimal solution set database.

[0044] See Figure 2 Specifically, firstly, an initial population of size N is randomly generated. After non-dominated sorting, the first generation of offspring is obtained through the three basic operations of selection, crossover, and mutation using a genetic algorithm. Secondly, starting from the second generation, the parent and offspring populations are merged and subjected to fast non-dominated sorting. At the same time, the crowding degree of individuals in each non-dominated layer is calculated, and suitable individuals are selected to form a new parent population based on the non-dominated relationship and the crowding degree of the individuals. Finally, a new offspring population is generated through the basic operations of the genetic algorithm, and so on, until the termination condition is met.

[0045] Based on the optimal solution set, a market model is established by introducing market-based decision factors, and the maximum value of the market model is calculated to determine the optimal design variables.

[0046] Specifically, the market model includes a revenue model and a cost model. The revenue model includes freight revenue and charter revenue. Freight revenue depends on the shipping route, cargo type, market supply and demand, etc., while charter revenue refers to the rental fees collected from leasing the vessel to charterers according to the charter contract.

[0047] Establish a cost model, which includes vessel acquisition costs, operating costs, management costs, and financing costs. Vessel acquisition costs include the expenses for purchasing or building the vessel; operating costs cover crew salaries, fuel costs, maintenance, material supplies, insurance, etc.; management costs include the shipowner's management fees, office expenses, marketing expenses, etc.; financing costs: if there is a loan for vessel acquisition, loan interest expenses need to be considered.

[0048] Set an influence factor 'a' for the revenue model and an influence factor 'b' for the cost model. The market model is represented as: Revenue Model × a - Cost Model × b. Then, calculate the maximum value of the market model based on the optimal solution set. The set of design variables that maximizes the value of the market model is the optimal design.

[0049] For example, for commercial ships, economic efficiency is the core factor influencing the selection of main dimensions, directly determining the ship's profitability and market competitiveness throughout its entire life cycle.

[0050] Table 1. Analysis of Speed ​​and Voyages

[0051]

[0052] The speed can be increased by one voyage per year from 16 knots to 20 knots; if the design speed is 20 knots, the corresponding optimal deadweight tonnage is 77,000 deadweight tons, and 6 voyages can be operated per year, with an annual capacity of about 460,000 deadweight tons; if the design speed is 16 knots, the corresponding optimal deadweight tonnage is 83,000 deadweight tons, and 5 voyages can be operated per year, with an annual capacity of about 420,000 deadweight tons.

[0053] Short-term charter revenue: High speed can significantly increase annual capacity and shipowners’ revenue in the short term. Generally speaking, the demand for high speed often depends on the timeliness of the charter, i.e., “delivering the specified tonnage within the specified time”.

[0054] Impact on costs and expenses: Behind the significant increase in transport capacity is the increase in other costs such as "ship maintenance costs, dock berthing costs, waterway passage costs, and tugboat assistance costs" brought about by the increase in voyages. At the same time, high speeds also have the problem of stalling in bad sea conditions.

[0055] While high speed and frequent voyages can improve short-term capacity and revenue, the non-linear growth of fuel, maintenance, and operating costs throughout the lifecycle significantly erodes long-term value. For the entire lifecycle of a vessel, a speed of 16 knots is more conducive to generating stable long-term revenue, aligning with the cost control and operational reliability requirements of charters of 10 years or more. This is particularly suitable for scenarios like ethane carriers, which require long-term commitment to both gas sources (such as US shale gas) and destinations (such as China). When the market model calculates the optimal combination as a speed of 16 knots and a deadweight tonnage of 83,000 tons, the corresponding design variables can be determined, with the main dimensions being a length of 274 meters, a beam of 41.6 meters, a draft of 11.9 meters, a block coefficient of 0.81, and a depth of 25 meters.

[0056] This embodiment also discloses a storage medium storing a computer program, which, when executed by a processor, implements the ship main size selection design method as described above.

[0057] This embodiment also discloses a terminal, which includes a processor and a memory; the memory is used to store computer programs; the processor is connected to the memory and is used to execute the computer programs stored in the memory, so that the terminal executes the ship master size selection design method as described above.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for selecting and designing the main dimensions of a ship, characterized in that, include: Design variables are established based on the ship's main dimensions; Establish a database of ship type evaluation indicators and constraint functions; Construct the objective function for the evaluation indicators; A genetic evolutionary algorithm is introduced to solve the objective function and obtain an optimal solution set database. A market model is established based on the optimal solution set, and the maximum value of the market model is calculated to determine the optimal design variables.

2. The ship main dimension selection and design method according to claim 1, characterized in that: The main dimensions of the vessel include length, beam, draft, block coefficient, and depth.

3. The ship main dimension selection and design method according to claim 1, characterized in that: The evaluation indicators include deadweight, speed, fuel consumption, cargo capacity, deadweight utilization rate, naval constant, cargo capacity utilization rate, fuel consumption per ton-nautical mile, and total tonnage to deadweight ratio.

4. The ship main dimension selection and design method according to claim 1, characterized in that: The constraint function database includes speed performance constraint functions and stability performance constraint functions.

5. The ship main dimension selection and design method according to claim 4, characterized in that: The constraint function database also includes restrictions on the maximum permissible cargo hold capacity, length, beam, maximum draft, and air draft of ships at global ethane receiving terminals and ethane export terminals, as well as ship specification requirements.

6. The ship main dimension selection and design method according to claim 1, characterized in that: The market model includes a revenue model and a cost model. An influencing factor 'a' is set for the revenue model, and an influencing factor 'b' is set for the cost model. The market model = revenue model × a - cost model × b.

7. A storage medium, characterized in that: The storage medium stores a computer program, which, when executed by a processor, implements the ship main size selection design method according to any one of claims 1 to 6.

8. A terminal, characterized in that: The terminal includes a processor and a memory; the memory is used to store computer programs; the processor is connected to the memory and is used to execute the computer programs stored in the memory, so that the terminal executes the ship main size selection design method according to any one of claims 1 to 6.

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