Ship global deformation and optimization method considering drainage volume precision control and deformation rationality, program, equipment and storage medium
By using analytical expressions and surrogate models to predict the volume changes and rationality after ship deformation, the problem of inaccurate volume change prediction in existing technologies is solved, and efficient and reliable ship optimization is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN ENG UNIV
- Filing Date
- 2026-01-20
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies lack analytical methods to directly predict volume changes before deformation, which leads to the need for extensive trial and error in ship optimization processes, resulting in high computational costs and limited reliability of results.
By establishing an analytical expression for the change in displacement volume and a criterion for the geometric rationality of the deformed hull, a rule-based design space and deformation rationality constraints are constructed. A surrogate model is used to predict the performance indicators after deformation, and the optimal design parameters are directly obtained by combining numerical optimization algorithms.
It enables precise control of volume changes and determination of ship hull rationality without actual deformation, significantly improving the efficiency and reliability of ship hull optimization and reducing repeated adjustments and recalculations.
Smart Images
Figure CN122021279A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of intelligent digital optimization design technology for ships, specifically relating to a method, program, equipment, and storage medium for global deformation and optimization of ships that considers precise control of drainage volume and rationality of deformation. Background Technology
[0002] Ship hull lines have a significant impact on hydrodynamic performance, with the displacement volume of the hull having a particularly pronounced effect on drag performance. Current technologies lack analytical methods to directly predict volume changes before deformation, leading to optimization processes relying heavily on trial and error, resulting in high computational costs and limited reliability. Therefore, achieving efficient and precise control of volume changes during optimization has been a key research focus in this field.
[0003] Current practices typically begin by defining the design space and selecting several sample points. The volume change corresponding to each sample point is then calculated to verify whether the volume constraints are met. If met, subsequent optimization continues based on these sample points; otherwise, the design space needs to be reduced and the above process repeated. This method is essentially an experience-based, step-by-step trial-and-error and iterative debugging process, which is inefficient. Furthermore, after optimization, the final ship form usually needs volume verification; if the results still do not meet the constraints, the design space may need to be readjusted and optimized again. The overall process exhibits significant empirical and iterative characteristics. Summary of the Invention
[0004] The purpose of this invention is to provide a method, program, equipment, and storage medium for global deformation and optimization of ships that considers precise control of drainage volume and the rationality of deformation. It can directly obtain the change in drainage volume after deformation and determine the rationality of the new ship type by taking the values of design variables without actual deformation.
[0005] A method for global deformation and optimization of a ship that considers precise control of displacement volume and rational deformation includes the following steps:
[0006] Determine the original ship type and displacement volume control range, and along the length of the original ship type, take the starting position of the deformation region, the ending position of the deformation region, the position of the fixed cross section within the deformation region, and the amplitude of the global deformation modification function as the optimization targets.
[0007] Determine the upper and lower limits of each parameter's value to construct a rule design space; collect samples in the rule design space, with each sample representing a set of optimization target parameters, to obtain an initial sample set;
[0008] Construct deformation rationality constraints, and take the intersection of the rule design space and the deformation rationality constraints as the optimization design space;
[0009] The initial sample set is filtered to remove samples that do not meet the deformation rationality constraints; for the remaining samples, the true performance index of the globally deformed ship type corresponding to each sample is obtained; a surrogate model is constructed, which can output the performance index estimate of the globally deformed ship type corresponding to the input sample based on the input sample.
[0010] Set the number of stations and their horizontal coordinates. Cut the original ship shape into transverse sections along the ship's length at each station's horizontal coordinate. Calculate the area of each cross section and construct a two-dimensional point set of the station's horizontal coordinate and its corresponding cross section area.
[0011] Lagrange interpolation is performed on the two-dimensional point set to obtain the polynomial expression of the area curve of the original ship shape cross section. Based on the parameters in the polynomial, the volume change expression of the ship shape after global deformation corresponding to the sample is constructed. Then, the volume change constraint condition of the ship shape after global deformation is constructed according to the displacement volume control interval.
[0012] Within the optimization design space, the surrogate model is used as the objective function. Optimization is performed based on the volume change constraint of the hull after global deformation. A set of optimization objective parameters that satisfy the volume change constraint of the hull after global deformation and correspond to the optimal performance index are obtained. Global deformation of the original hull is then performed based on this set of optimization objective parameters.
[0013] Furthermore, the global deformation modification function for:
[0014]
[0015] in, and The starting and ending positions of the deformation area along the length of the original hull shape; The amplitude of the global deformation modification function; The position of the fixed cross section within the deformation area.
[0016] Furthermore, the aforementioned deformation rationality constraints for:
[0017]
[0018] Furthermore, the determination of the upper and lower limits of each parameter's value constructs a rule design space. ;
[0019]
[0020] In the space of rule design Samples collected in China Each sample For a set of optimization target parameters, This yields the initial sample set;
[0021] The rule design space Deformation rationality constraints The intersection of these elements serves as the basis for optimizing design space. ;
[0022] The initial sample set is filtered to remove samples that do not meet the deformation rationality constraints; for the remaining samples... Obtain the true performance indicators of the ship hull after global deformation for each sample. ; Constructing a proxy model Proxy model It can output an estimate of the performance index of the ship hull after global deformation based on the input sample. ,Right now .
[0023] Furthermore, the number of stations set x-coordinate of station , For the original ship type, along the length direction, the x-coordinate of each station Perform cross-sectional cutting and calculate the area of each cross-section. Specifically:
[0024] Get the x-coordinate of the station Discrete grid points on the corresponding cross section , The area of the cross section is calculated using Green's formula. ;
[0025]
[0026] in, , ;
[0027] Construct the horizontal axis of the station Area of its corresponding cross section Two-dimensional point set .
[0028] Furthermore, the two-dimensional point set By performing Lagrange interpolation, a polynomial expression for the area curve of the original ship's transverse section is obtained. ;
[0029]
[0030]
[0031] Based on the parameters in this polynomial Construct an expression for the volume change of the ship hull after global deformation corresponding to the sample. :
[0032]
[0033]
[0034]
[0035] Then, control the range based on the drainage volume. Construct constraints on the volume change of the ship shape after global deformation;
[0036]
[0037] Furthermore, the aforementioned optimization design space Internally, the proxy model will be implemented. As the objective function, the constraint is based on the volume change of the hull shape after global deformation. The optimization process is performed to obtain a set of target parameters that satisfy the constraints on the volume change of the hull after global deformation and correspond to the optimal performance index. The original ship form undergoes global deformation based on the set of optimization target parameters.
[0038] A computer device includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above-described method for global deformation and optimization of a ship that considers precise control of displacement volume and rationality of deformation.
[0039] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method for global deformation and optimization of a ship that considers precise control of displacement volume and rationality of deformation.
[0040] A computer program product includes computer instructions that, when executed by a processor, implement the steps of the above-described method for global deformation and optimization of a ship, taking into account precise control of displacement volume and rationality of deformation.
[0041] The beneficial effects of this invention are as follows:
[0042] This invention derives an analytical expression for the change in displacement volume with respect to global deformation parameters based on numerical integration and recursive formulas. It determines the range of reasonable deformation parameters for the hull geometry based on a global deformation modification function and a rule-based design space. This allows for the direct prediction of the corresponding volume change based on design parameters without actual hull deformation, thus achieving precise feedforward control of volume constraints and direct determination of the reasonableness of deformable hulls. Furthermore, a surrogate model is used to achieve rapid optimization of any hull structure under reasonable deformation and precise volume control constraints. This invention transforms the traditional iterative "design-verification-adjustment" process into a deterministic one-step calculation, enabling subsequent optimization to be carried out directly within a pre-verified reasonable design space. This significantly reduces the need for repeated adjustments and calculations, greatly improving the computational efficiency, convergence reliability, and engineering practicality of hull optimization. Attached Figure Description
[0043] Figure 1 This is a flowchart of the present invention.
[0044] Figure 2 These are the front view and global view of the deformable ship in an example of the present invention.
[0045] Figure 3 This represents the reasonable range of parameters for the deformable vessel in the examples of this invention.
[0046] Figure 4 This is a distribution diagram of sample points in an example of the present invention.
[0047] Figure 5 This is a schematic diagram illustrating the acquisition of the cross-sectional curve polynomial expression in an example of the present invention.
[0048] Figure 6 This is a cross-sectional comparison diagram of the optimal ship type and the parent ship in the examples of the present invention.
[0049] Figure 7 This is a comparison diagram of the free surface wave height of the optimized hull form and the parent hull form obtained based on potential flow theory in an example of the present invention.
[0050] Figure 8 This is a comparison diagram of the surface dynamic pressure distribution of the optimized hull form and the parent hull form obtained based on potential flow theory in an example of the present invention. Detailed Implementation
[0051] The present invention will now be further described with reference to the accompanying drawings.
[0052] This invention proposes a novel approach to hull form optimization based on analytical prediction. By establishing an analytical expression for volume change, the volume change corresponding to any design parameter can be directly calculated without actual deformation of the hull. Simultaneously, based on the principles of differential calculus, the geometric rationality criterion of the deformed hull is derived, thereby clarifying the effective range of the design parameters. This process is a deterministic one-step calculation, ensuring that subsequent optimization can be carried out directly within the pre-verified volume change and reasonable design space, significantly improving the efficiency and usability of hull form optimization results.
[0053] A method for global deformation and optimization of a ship that considers precise control of displacement volume and rational deformation includes the following steps:
[0054] Step 1: Determine the original ship type and displacement volume control range ;
[0055] Establish a Cartesian coordinate system, where The axis runs along the length of the ship and points towards the stern; The axis runs along the width of the ship and points to the starboard side; The axis points vertically upwards along the draft direction;
[0056] Along the length of the original hull shape, the starting position of the deformation area is determined. Termination position of deformation area The position of the fixed cross section within the deformation area Global transformation modification function amplitude As a target for optimization;
[0057] The global deformation modification function for:
[0058]
[0059] Determine the upper and lower limits of each parameter's value to construct the rule design space. ;
[0060]
[0061] In the space of rule design Samples collected in China To obtain the sample set ;
[0062] Based on the global deformation modification function And the sample values are used to geometrically deform the original ship shape. Indicates that it is located at Longitudinal displacement of the cross section at the location; based on the sample The value of is determined by... The cross section within the range moves along the X direction. A new sample ship type was obtained.
[0063] Step 2: Modify based on global deformation function and rule design space Constructing deformation rationality constraints ;
[0064] To ensure the geometric accuracy and rationality of the deformed hull, the relationship between the slopes of the curves before and after modification at the same ordinate under the control of the global deformation modification function is required within the start and end regions of the deformation, i.e., when... When designing variables The range of values for is:
[0065]
[0066] Take the rule design space Deformation rationality constraints The intersection of these elements serves as the basis for optimizing design space. ;
[0067] Step 3: For the sample set Perform a screening process to remove items that do not meet the constraints on the rationality of deformation. From the samples, a reasonable sample set is obtained. ;
[0068] Obtain a reasonable sample set Each sample The actual performance indicators of the ship hull after global deformation Build a proxy model Proxy model It can output an estimate of the performance index of the ship hull after global deformation based on the input sample. ,Right now ;
[0069] It can construct surrogate models such as Kriging or response surface for the relationship between performance indices and deformation parameters.
[0070] Step 4: Set the number of stations x-coordinate of station , For the original ship type along the length direction Cross-sectional sections were cut at different stations, and the area of each cross-section was calculated. Construct the horizontal coordinate of the station Area of its corresponding cross section Two-dimensional point set ;
[0071] The x-coordinate of the calculated station Area of the corresponding cross section Specifically:
[0072] Each cross-section can be viewed as a smooth closed curve in a two-dimensional rectangular coordinate system with the y-axis as the abscissa and the z-axis as the ordinate. Let the region enclosed by this smooth closed curve be denoted as . , yes Discrete points on the boundary are approximated by discrete sums, and the area of the cross section is calculated using Green's formula. ;
[0073]
[0074] in, , ;
[0075] Step 5: For the two-dimensional point set By performing Lagrange interpolation, a polynomial expression for the area curve of the original ship's transverse section is obtained. ;
[0076] For different and its corresponding function value The Lagrange interpolation polynomial is obtained. ,in It is a basis polynomial, defined as , satisfying the property After sorting, we get The polynomial expression is:
[0077]
[0078] satisfy The following system of linear equations is obtained:
[0079]
[0080] Right now:
[0081]
[0082] Let V be the coefficient matrix on the left, then:
[0083]
[0084] According to parameters , Construct the target vector The expression for the volume change of the ship shape after global deformation ;
[0085]
[0086]
[0087]
[0088] Step 6: Optimize the design space With drainage volume control zone As a constraint:
[0089] ,
[0090] proxy model As the objective function, optimization is performed to obtain the target vector that satisfies the constraints and corresponds to the optimal performance index. Based on the target vector and the global deformation modification function, the global deformation of the original ship form is performed.
[0091] The solution is obtained using constrained numerical optimization algorithms, such as intelligent optimization algorithms that incorporate penalty function mechanisms.
[0092] Example 1:
[0093] In a specific embodiment of the present invention, a Series 60 ship model was selected (the main parameters of which are: length between perpendiculars of 3.932m, length between waterlines of 4m, beam of 0.524m, draft of 0.21m, and wetted surface area of 2.662m²). 2 The drainage volume is V0 = 0.26 m³. 3 Its mass is 130.176 kg, and its three-dimensional geometry is as follows: Figure 2 As shown, (using the example ship type) variables are set. The rule design space is set as .
[0094] The deformed area is the first half. To modify the amplitude of the function; It refers to the location of the fixed cross-section within the deformation area. (Based on the sample) The value of is determined by... The cross section within the range moves along the positive x-axis. New sample ship types were obtained, and the sample set is as follows: , .
[0095] To ensure the geometric accuracy and rationality of the deformed hull, the relationship between the slopes of the curves before and after modification at the same ordinate under the control of the global deformation modification function is required within the start and end regions of the deformation, i.e., when... When designing variables The range of values for is:
[0096]
[0097] Its schematic diagram is as follows Figure 3 As shown.
[0098] Combined with design space The reasonable range of variation for the final parameters is obtained as follows: .
[0099] In design space The optimal Latin hypercube sampling method was used to obtain 50 sample ship types, and their sample distribution points are as follows: Figure 4 As shown, 50 sample ship types were deformed based on a modified function, and the total static resistance of the 50 sample ship types at a Froude number Fr = 0.4 was calculated based on potential flow theory. Based on these sample data, a model was constructed to describe the total static resistance with respect to the deformation parameters. Kriging proxy model between;
[0100] Random selection The cross-section at the station can be viewed as a smooth closed curve in a two-dimensional rectangular coordinate system with the y-axis as the abscissa and the z-axis as the ordinate. Let the region enclosed by this smooth closed curve be denoted as . , yes Discrete points on the boundary are approximated by discrete sums, yielding... Approximate cross-sectional area at the station This yields a two-dimensional point set containing the x-coordinate of each station and its corresponding cross-sectional area value. .
[0101] Lagrange interpolation of a two-dimensional point set yields a polynomial expression for the cross-sectional area curve. The schematic diagram is as follows Figure 5 As shown, where The coefficients The values are shown in the table below:
[0102]
[0103] Polynomial expression based on the obtained cross-sectional area curve The change in volume can be expressed as:
[0104]
[0105] in, The recursive formula is:
[0106]
[0107] And the initial value is , ;
[0108] The recursive formula is:
[0109]
[0110] And the initial value is , .
[0111] Will The coefficients Substitution get:
[0112]
[0113] Set a threshold for drainage volume change. ,in Given the displacement volume before deformation, and taking the minimum total static resistance at Fr = 0.4 as the objective function, a constrained particle swarm optimization algorithm is used to solve for the ship design parameters and corresponding sample ship types that minimize the total resistance while satisfying the constraints of displacement volume variation range and deformation rationality.
[0114]
[0115] The optimal design variables are shown in the table below.
[0116]
[0117] Comparison of transverse sections between the optimal Series 60 ship type and the parent ship type. Figure 6 As shown, blue represents the cross-sectional curve of the parent ship type, and red represents the cross-sectional curve of the optimal Series 60 ship type.
[0118] To ensure the reliability of the optimization results and for further analysis, the potential flow method was used to calculate the performance of the parent ship and the optimal hull, obtaining their... Total resistance at time, total resistance of the parent ship and the optimized ship type The comparison is shown in the table below.
[0119]
[0120] As can be seen from the table above, compared with the total resistance of the original Series 60 ship, the total resistance of the optimized ship type is significantly reduced, by about 12.55%, indicating that the optimization effect is good. In addition, the total resistance value of the optimal ship type obtained by the Kriging surrogate model is 56.755N, and the resistance value predicted by the potential flow theory is 56.697N. The two are very close, indicating that the Kriging surrogate model has high accuracy, which further demonstrates the reliability of the optimal value obtained by the optimization algorithm in this paper.
[0121] Figure 7The comparison of free-face wave-making between the parent ship and the optimized ship based on potential flow theory is shown. It can be seen that the bow wave system is significantly weakened, and the originally large area of high-intensity red wave peaks is significantly reduced. The stern wave system is also more gentle. Overall, the range and intensity of the wave peak areas are significantly reduced and decreased, and the wave-making is more converged near the hull, indicating that the optimized ship type generates less wave-making resistance during navigation.
[0122] Figure 8 The paper presents a comparison of the dynamic pressure distribution on the hull surface of the optimized hull form and the parent hull form based on potential flow theory. It can be observed that the range of both high-pressure and low-pressure areas on the hull surface is significantly reduced.
[0123] This invention considers the precise control of displacement volume and the rationality of hull geometry after deformation during the global deformation process of different ship types. Based on numerical integration and recursive formulas, it provides an analytical expression for the change in hull displacement volume under translational deformation, solving the problems of not being able to directly predict the change in displacement volume based on design variables before deformation and the difficulty in accurately feeding forward control of volume constraints. By establishing a criterion for judging the geometric feasibility of the deformed hull based on the principle of differential calculus, a reasonable range of deformation parameters can be determined in advance, thereby transforming the traditional "design-verification-adjustment" empirical iterative process into a deterministic one-step calculation, significantly improving the efficiency and reliability of ship type optimization.
[0124] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for global deformation and optimization of a ship that considers precise control of displacement volume and rationality of deformation, characterized in that: Determine the original ship type and displacement volume control range, and along the length of the original ship type, take the starting position of the deformation region, the ending position of the deformation region, the position of the fixed cross section within the deformation region, and the amplitude of the global deformation modification function as the optimization targets. Determine the upper and lower limits of each parameter's value to construct a rule design space; collect samples in the rule design space, with each sample representing a set of optimization target parameters, to obtain an initial sample set; Construct deformation rationality constraints, and take the intersection of the rule design space and the deformation rationality constraints as the optimization design space; The initial sample set is filtered to remove samples that do not meet the constraints on the rationality of deformation; For the remaining samples, obtain the actual performance indicators of the ship type after global deformation for each sample; Construct a proxy model that can output an estimate of the performance index of the ship type after global deformation based on the input sample. Set the number of stations and their horizontal coordinates. Cut the original ship shape into transverse sections along the ship's length at each station's horizontal coordinate. Calculate the area of each cross section and construct a two-dimensional point set of the station's horizontal coordinate and its corresponding cross section area. Lagrange interpolation is performed on the two-dimensional point set to obtain the polynomial expression of the area curve of the original ship shape cross section. Based on the parameters in the polynomial, the volume change expression of the ship shape after global deformation corresponding to the sample is constructed. Then, the volume change constraint condition of the ship shape after global deformation is constructed according to the displacement volume control interval. Within the optimization design space, the surrogate model is used as the objective function. Optimization is performed based on the volume change constraint of the hull after global deformation. A set of optimization objective parameters that satisfy the volume change constraint of the hull after global deformation and correspond to the optimal performance index are obtained. Global deformation of the original hull is then performed based on this set of optimization objective parameters.
2. The method for global deformation and optimization of a ship considering precise control of displacement volume and rationality of deformation as described in claim 1, characterized in that: The global deformation modification function for: in, and The starting and ending positions of the deformation area along the length of the original hull shape; The amplitude of the global deformation modification function; The position of the fixed cross section within the deformation area.
3. The method for global deformation and optimization of a ship considering precise control of displacement volume and rationality of deformation as described in claim 2, characterized in that: The deformation rationality constraint conditions for: 。 4. The method for global deformation and optimization of a ship considering precise control of displacement volume and rationality of deformation as described in claim 3, characterized in that: The upper and lower limits of each parameter's value are determined to construct the rule design space. ; In the space of rule design Samples collected in China Each sample For a set of optimization target parameters, This yields the initial sample set; The rule design space Deformation rationality constraints The intersection of these elements serves as the basis for optimizing design space. ; The initial sample set is filtered to remove samples that do not meet the deformation rationality constraints; for the remaining samples... Obtain the true performance indicators of the ship hull after global deformation for each sample. ; Constructing a proxy model Proxy model It can output an estimate of the performance index of the ship hull after global deformation based on the input sample. ,Right now .
5. A method for global deformation and optimization of a ship considering precise control of displacement volume and rationality of deformation, as described in claim 4, is characterized in that: The number of stations set x-coordinate of station , For the original ship type, along the length direction, the x-coordinate of each station Perform cross-sectional cutting and calculate the area of each cross-section. Specifically: Get the x-coordinate of the station Discrete grid points on the corresponding cross section , The area of the cross section is calculated using Green's formula. ; in, , ; Construct the horizontal axis of the station Area of its corresponding cross section Two-dimensional point set .
6. The method for global deformation and optimization of a ship considering precise control of displacement volume and rationality of deformation as described in claim 5, characterized in that: The two-dimensional point set By performing Lagrange interpolation, a polynomial expression for the area curve of the original ship's transverse section is obtained. ; Based on the parameters in this polynomial Construct an expression for the volume change of the ship hull after global deformation corresponding to the sample. : Then, control the range based on the drainage volume. Construct constraints on the volume change of the ship shape after global deformation; 。 7. A method for global deformation and optimization of a ship considering precise control of displacement volume and rationality of deformation as described in claim 6, characterized in that: The aforementioned in the optimization design space Internally, the proxy model will be implemented. As the objective function, the constraint is based on the volume change of the hull shape after global deformation. The optimization process is performed to obtain a set of target parameters that satisfy the constraints on the volume change of the hull after global deformation and correspond to the optimal performance index. The original ship form undergoes global deformation based on the set of optimization target parameters.
8. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.
9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When executed by a processor, the computer program implements the steps of the method according to any one of claims 1 to 7.
10. A computer program product comprising computer instructions, characterized in that: When executed by a processor, the computer instructions implement the steps of the method according to any one of claims 1 to 7.