Method and device for fast estimation of hydrostatic characteristics during hull geometric deformation process

Abstract

This invention discloses a method and device for rapid prediction of hydrostatic characteristics during hull geometric deformation, belonging to the interdisciplinary field of marine engineering and computer-aided design. The method calculates initial hydrostatic parameters based on an initial three-dimensional geometric model of the hull; discretizes the geometric model into a triangular mesh model, applies a small perturbation to each mesh vertex, and calculates the sensitivity using the finite difference method based on the changes in hydrostatic parameters; mesh vertices near the waterline employ a one-sided constrained perturbation strategy; establishes a free-form deformation (FFD) control frame covering the hull model, and determines the mapping relationship between each mesh vertex and the FFD control point after perturbation; couples the sensitivity of each mesh vertex with the mapping relationship to construct a control point-level sensitivity matrix; obtains the displacement of the FFD control points after perturbation, and calculates the changes in hydrostatic parameters using a multi-precision prediction strategy. This method avoids repeatedly performing complete hydrostatic calculations during the interactive process by constructing a control point-level hydrostatic mapping model.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of marine engineering and computer-aided design, and in particular to a method and device for rapid prediction of hydrostatic characteristics during hull geometric deformation. Background Technology

[0002] In the process of overall ship design and hull optimization, even minor changes in hull lines can significantly affect hydrostatic characteristics such as displacement volume, center of buoyancy, and wetted surface area. These hydrostatic parameters are important fundamental indicators for ship stability analysis, resistance calculation, and propulsion system matching, and therefore need to be frequently evaluated during the hull design phase.

[0003] In existing ship design processes, hydrostatic parameters are typically calculated precisely based on a complete three-dimensional hull model using methods such as numerical integration or geometric intersection. This type of calculation involves operations such as traversing the hull surface mesh, determining waterlines, and volume decomposition, resulting in high computational complexity and making it difficult to meet the real-time feedback requirements during the hull's geometric deformation processes.

[0004] When parametrically editing a hull model using the Free Form Deformation (FFD) method, designers typically need to repeatedly adjust the local or overall hull lines by dragging control points. Performing a complete hydrostatic calculation after each control point displacement would severely impact interactive efficiency; while calculating hydrostatic parameters only after deformation is complete would fail to provide designers with immediate references during the design process, reducing the efficiency and reliability of parametric design.

[0005] Furthermore, directly applying general sensitivity analysis or linear approximation methods to ship hydrostatic calculations is easily affected by factors such as geometric discontinuities near the waterline and large variations in the displacement of control points, leading to insufficient stability and engineering applicability of the predicted results. Therefore, it is necessary to propose a real-time prediction method for hydrostatic characteristics oriented towards ship geometric deformation scenarios. Summary of the Invention

[0006] The purpose of this invention is to provide a method for real-time prediction of hydrostatic characteristics during hull deformation. By constructing a unified calculation framework of "grid vertex sensitivity - FFD control point mapping - multi-precision prediction model" and introducing a waterline region-restricted disturbance mechanism, the method can achieve rapid and stable prediction of hydrostatic parameters during the geometric interactive deformation of the hull.

[0007] This invention provides a method for rapid prediction of hydrostatic characteristics during hull geometric deformation by coupling sensitivity analysis with free-form deformation, comprising the following steps:

[0008] Calculate the initial hydrostatic parameters based on the initial three-dimensional geometric model of the hull;

[0009] The initial three-dimensional geometric model of the hull is discretized into a triangular mesh model. A small perturbation is applied to each mesh vertex, and the sensitivity is calculated using the finite difference method based on the changes in hydrostatic parameters. Among them, the mesh vertices located near the waterline are subjected to a one-sided constrained perturbation strategy.

[0010] Establish a free-form deformation (FFD) control frame covering the hull model, and determine the mapping relationship between each mesh vertex and the FFD control point after perturbation; based on the chain rule, couple the sensitivity of each mesh vertex with the mapping relationship to construct a control point-level sensitivity matrix;

[0011] During the hull deformation process, the displacement of the FFD control points is obtained, and the changes in hydrostatic parameters are calculated using a multi-precision prediction strategy.

[0012] Furthermore, the hydrostatic parameters include the drainage volume, the center of buoyancy, and the wetted surface area; the drainage volume and the position of the center of buoyancy are calculated using a method based on patch integration.

[0013] Furthermore, the sensitivity is calculated as follows:

[0014]

[0015] in, For the first The unit displacement of the first grid vertex causes the first... Rate of change of hydrostatic parameters; For the first One hydrostatic parameter; For the first The coordinates of each grid vertex; For the first The tiny perturbation increment of each grid vertex , This refers to the length of the ship's hull.

[0016] Furthermore, the grid vertices near the waterline The axis coordinate is less than the preset distance The grid vertices within; the preset distance The perturbation frequency is 0.5% to 5% of the ship's draft T. The single-sided confined perturbation strategy is as follows: For grid vertices near the waterline below the waterline, a perturbation is applied in the direction pointing towards the inside of the ship, with the perturbation direction being positive; for grid vertices near the waterline above the waterline, a perturbation is applied in the direction towards the air domain, with the perturbation direction being positive.

[0017] When the disturbance direction is positive, the forward difference scheme is as follows:

[0018] .

[0019] Furthermore, the FFD control frame is sized to completely enclose the hull and expands outward by 2% to 10% of the hull length in each direction, and the control points are arranged in a regular network.

[0020] Furthermore, the geometric mapping relationship between each mesh vertex and the FFD control point of the perturbed triangular mesh model is as follows:

[0021]

[0022]

[0023] in, For the first time after adding perturbation The coordinates of each grid vertex; For the first Coordinates of one FFD control point; These are the weighting coefficients; It is a Bernstein polynomial; , , The order of the FFD in each direction; , , FFD parameter space , , The control point indices in the direction have the following value ranges: , , ; Let be the coordinates of the vertex in the parameter space.

[0024] Furthermore, the control point-level sensitivity is:

[0025]

[0026] The control point level sensitivity matrix for:

[0027]

[0028] Among them, matrix elements For the first The displacement of the FFD control point affects the first... Sensitivity of a hydrostatic parameter.

[0029] Furthermore, based on the displacement amplitude A multi-precision prediction strategy is used to calculate hydrostatic parameters;

[0030] when When using a linear model: , The displacement of the FFD control point during the application of the disturbance;

[0031] when At that time, a response surface model containing second-order terms is adopted: The second-order response matrix The results were obtained by fitting using the response surface methodology, specifically: first, several groups satisfying the following conditions were selected. Control point displacement samples For each sample group, the complete hydrostatic force is calculated using the wetted surface numerical integration method corresponding to the updated triangular network model with added perturbation, and the corresponding hydrostatic parameter changes are obtained. ; Given the sensitivity matrix Based on this, the following second-order polynomial approximation model is constructed. The corresponding samples of each group , , Substitute the values ​​into the approximate model and fit the coefficients of the second-order terms in the approximate model using the least squares method; The complete hydrostatic calculation is substituted into the second-order polynomial approximation model for synchronization. and renew.

[0032] Furthermore, the threshold and Determined based on error control criteria; when the linear model prediction error is less than 1%, the corresponding displacement amplitude... for When the second-order model prediction error is less than 3%, the corresponding displacement amplitude is... for The error was obtained by comparing the complete hydrostatic calculation results.

[0033] The present invention also provides a computer device, including 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 method for rapid prediction of hydrostatic characteristics during hull geometric deformation based on sensitivity analysis and free-form deformation coupling described above.

[0034] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for rapid prediction of hydrostatic characteristics during hull geometric deformation based on sensitivity analysis and free-form deformation coupling as described above.

[0035] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method for rapid prediction of hydrostatic characteristics during hull geometric deformation based on sensitivity analysis and free-form deformation coupling as described above.

[0036] The beneficial effects of this invention are as follows:

[0037] This invention constructs a control point-level hydrostatic mapping model, avoiding repeated execution of complete hydrostatic calculations during the interaction process. If the displacement of the moved control point is small, i.e., using first-order linear or second-order correction to calculate hydrostatic parameters, it typically only takes a few milliseconds, almost at the second feedback level. In contrast, complete hydrostatic calculations, where each control point movement is risky due to excessive deformation leading to exceeding the displacement volume constraint, usually take several seconds. This significantly improves computational efficiency; moving the control point allows for understanding the changing trend of the ship's hydrostatic forces, improving the design efficiency of hull optimization. By introducing a constrained disturbance strategy near the waterline, the stability and engineering applicability of the sensitivity model are improved. A multi-precision adaptive switching mechanism achieves a dynamic balance between computational efficiency and prediction accuracy. It is suitable for real-time feedback requirements in the parametric design and optimization process of hulls. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall process of the method of the present invention;

[0039] Figure 2 A schematic diagram of the hydrostatic sensitivity calculation and waterline processing strategy at the grid vertex level;

[0040] Figure 3 A schematic diagram showing the mapping relationship and deformation between FFD control points and the hull mesh;

[0041] Figure 4 A schematic diagram of the adaptive switching mechanism for hydrostatic parameter prediction accuracy;

[0042] Figure 5 This is a functional module structure diagram of the system of the present invention. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings. The embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0044] This invention discloses a method for rapid prediction of hydrostatic characteristics during hull geometric deformation based on sensitivity analysis and free-form deformation coupling. Figure 1 As shown. First, the initial hull geometry model is discretized into a triangular mesh model, and all vertices are extracted. The coordinates were then determined. Subsequently, the initial drainage volume was calculated using the hydrostatic integral formula. Floating center coordinates and wet surface area The core process is completed in the preprocessing stage: the system applies a small perturbation to each grid vertex, calculates its sensitivity to hydrostatic parameters, and, combined with the geometric interpolation function of the FFD control frame, derives a global mapping matrix of "control point displacement - hydrostatic parameter change". In the interactive stage, the system only needs to monitor the displacement vector of the control points, and can obtain the change in hydrostatic parameters in real time through matrix multiplication. Specifically, this includes the following steps:

[0045] S1: Discretize the initial three-dimensional geometric model of the hull into a triangular mesh model to obtain the set of mesh vertices;

[0046] The triangular mesh model preferably uses a closed mesh that meets the watertightness requirement to ensure the accuracy of volume integrals in hydrostatic calculations. At the same time, the mesh size should preferably meet the requirement that the mesh side length is (0.001~0.01)L to balance calculation accuracy and efficiency.

[0047] S2: Calculation of initial hydrostatic parameters based on a discrete model Including drainage volume Floating center coordinates and wet surface area The hydrostatic parameters are obtained by numerical integration over the wetted surface of the hull. It is preferred to use a patch integration method to calculate the displacement volume and the position of the center of buoyancy in order to improve the calculation stability.

[0048] S3: Apply a small perturbation to each grid vertex. The sensitivity is calculated using the finite difference method:

[0049]

[0050] in, For the first The unit displacement of the first grid vertex causes the first... Rate of change of hydrostatic parameters; For the first One hydrostatic parameter; For the first The coordinates of each grid vertex;

[0051] The finite difference method is preferred for calculating the perturbation at each grid vertex. The perturbation amplitude is related to the hull size and satisfies the following conditions: ,in This is to avoid amplifying numerical errors or distorting sensitivity.

[0052] For grid vertices located near the design waterline, spatial disturbances may cause the grid to cross the water surface, resulting in discontinuous changes in the drainage volume calculation. Therefore, a single-sided constrained disturbance strategy, which differs from that in ordinary areas, is adopted for this region to ensure the stability and physical rationality of the sensitivity calculation.

[0053] For the pre-set distance near the design waterline The grid vertices within the range are subjected to a one-sided constrained perturbation strategy; , Let be the vertical coordinate of the i-th grid vertex. The vertical coordinates of the current waterline; the distance near the waterline. To design the draft T, which is 0.5%~5%, and further 1%~2%, the determination is made by judging whether the height difference between the vertex and the waterline is less than d;

[0054] The unilateral perturbation direction is determined based on the position of the mesh vertex relative to the waterline. For mesh vertices below the waterline, only perturbations pointing towards the hull are applied; for mesh vertices above the waterline, only perturbations away from the waterline are applied. This avoids the adverse effects of abrupt changes in the waterline position during perturbation on the calculation of hydrostatic parameters. A forward difference scheme is used when the perturbation direction is positive.

[0055]

[0056] S4: Establish a free-form deformation (FFD) control frame covering the hull model. The optimal size of the FFD control frame is to completely enclose the hull model and expand outwards in all directions by (2%~10%) the ship's length. The optimal number of control points is (4~10)×(4~10)×(4~10) in three dimensions, arranged using a regular mesh. Define the control points. With perturbated mesh vertices Geometric mapping relationship:

[0057]

[0058]

[0059] in, For the first time after adding perturbation The coordinates of each grid vertex; For the first Coordinates of one FFD control point; For FFD control points For grid vertices The influence weighting coefficient; It is a Bernstein polynomial; , , The order of the FFD in each direction; , , FFD parameter space , , The control point indices in the direction have the following value ranges: , , ; Let be the coordinates of the vertex in the parameter space.

[0060] S5: Based on the chain rule, the vertex sensitivity is coupled with the FFD mapping relationship:

[0061]

[0062] Further, a control point-level sensitivity matrix is ​​constructed. The control point-level sensitivity is constructed in matrix form, and matrix multiplication is preferred for fast solution. ;

[0063]

[0064] This is the control point-level sensitivity matrix, and its elements are... This represents the change in the k-th hydrostatic parameter caused by the unit displacement of the i-th FFD control point, and is used to establish a linear quantitative mapping relationship between the control point displacement and the hydrostatic change.

[0065] S6: During the hull deformation process, obtain the displacement of the FFD control points. And calculate the hydrostatic parameter changes based on the mapping model; according to the displacement amplitude A multi-precision prediction strategy is adopted: when A linear model is used at this time: ;when When using a response surface model that includes second-order terms: ; This is the second-order response surface coefficient matrix, used to compensate for nonlinear errors under moderate deformation. Second-order response matrix. The results were obtained through response surface methodology fitting. The specific process included: selecting several groups that satisfied... Control point displacement samples Perform a complete hydrostatic calculation on each sample group to obtain the corresponding changes in hydrostatic parameters. Given the first-order sensitivity matrix Based on this, the following second-order polynomial approximation model is constructed: Substitute the sample data from each group into the model described above, and fit the coefficients of the second-order terms in the model using the least squares method to determine the matrix. Among them, matrix Each element characterizes the second-order coupling effect and nonlinear influence between the displacements of the control points.

[0066] During the hull deformation process, the sensitivity matrix is ​​further updated. With second-order matrix The sensitivity matrix is ​​updated using FFD control point displacements greater than T2. With second-order matrix ,when By performing a complete hydrostatic calculation and using the numerical integration method on the wetted surface of the updated hull mesh, accurate parameters such as displacement volume and center of buoyancy coordinates can be obtained. The changes in these hydrostatic parameters can then be used to determine the appropriate parameters. Substitute into the second-order polynomial approximation model and update synchronously. and .

[0067] Thresholds T1 and T2 are determined based on error control criteria. When the linear model prediction error is less than 1%, the corresponding displacement amplitude is defined as... When the second-order model prediction error is less than 3%, the corresponding displacement amplitude is defined as follows: The error was obtained by comparing the results of precise hydrostatic calculations.

[0068] Figure 2 This is a schematic diagram of the hydrostatic sensitivity calculation and waterline processing strategy at the grid vertex level. Figure 2 The hull cross section 201 and design waterline 202 are shown. To construct the sensitivity model, it is necessary to calculate the partial derivatives of the mesh vertex position changes with parameters such as displacement volume. Mesh points 203 in the ordinary region are calculated using conventional omnidirectional perturbation. However, for mesh points 204 in the waterline region located within a preset distance d near the design waterline 202, their position changes may cause mesh patches to cross the water surface, resulting in a nonlinear abrupt change in the influent volume. This embodiment adopts a "constrained perturbation strategy": for critical points below the water surface, only the impact of perturbation towards the deep water direction is calculated; for critical points above the water surface, only the impact of perturbation towards the air domain is calculated. This unilateral or constrained perturbation method 205 (represented by a unidirectional arrow in the figure) effectively avoids the failure of the linearization assumption at the waterline, significantly improving the robustness of the prediction model.

[0069] Figure 3 The FFD control frame 301 surrounding the hull 302 is shown. The control frame consists of several evenly distributed control points 303 (Q). j Composed of ) . The dashed line 304 in the diagram represents the control point relative to vertex 305 (P) of the hull mesh. i The geometric control rights (weighted influence) of the control point 303 are determined in step S5 of this invention. The chain rule is used to combine the "sensitivity of a vertex to hydrostatic forces" with the "geometric weight of a control point to a vertex," constructing a mapping model that directly connects control point 303 with hydrostatic parameters. When a control point is moved along the arrow direction 306 (i.e., a disturbance is added), the hull 302 deforms accordingly. The system does not need to use mesh vertices as intermediaries; it directly calculates the change in hydrostatic parameters ΔH based on the control point displacement ΔQ.

[0070] Figure 4 The mechanism shown is executed by the precision control module, aiming to balance calculation speed and accuracy. The horizontal axis represents the displacement amplitude of the FFD control points. When the displacement amplitude is in region 401 (less than the first preset threshold) When the displacement amplitude is in region 402 (between...), the system determines it to be a fine-tuning mode and adopts a linear prediction mode, which uses only the first-order sensitivity matrix for calculation, resulting in the fastest response speed. and When the displacement amplitude is in region 403 (greater than the second preset threshold), the system determines that the linearity error may increase and automatically switches to enhanced prediction mode, introducing a higher-order correction coefficient for compensation. When the displacement amplitude is in region 403 (greater than the second preset threshold), the system determines that the linearity error may increase and automatically switches to enhanced prediction mode, introducing a higher-order correction coefficient for compensation. When the hydrostatic force is detected, it indicates that the hull has undergone severe deformation, and the original linear or approximate model has failed. At this time, the system triggers the accurate calculation mode, performs a complete numerical integration based on the new deformed mesh (step S6), obtains accurate hydrostatic values, and uses these accurate values ​​to correct the mapping model (update the sensitivity matrix) to ensure the accuracy of the prediction benchmark for subsequent deformations.

[0071] Figure 5 The system of this invention mainly consists of a preprocessing module, an interactive deformation module, a hydrostatic estimation module, and a precision control module. The preprocessing module is responsible for the arduous matrix construction work during model loading (corresponding to steps S1-S5). The interactive deformation module provides a visual interface and outputs control point displacement information. The hydrostatic estimation module is the core calculation unit, receiving displacement information and combining it with the mapping model to output real-time data curves such as displacement and center of buoyancy. The precision control module acts like a monitor, monitoring the deformation amplitude in real time, dynamically adjusting the calculation strategy of the estimation module, and calling the background solver for precise updates when necessary.

[0072] Example 1

[0073] To verify the effectiveness and engineering applicability of the method of the present invention in real-time prediction of hydrostatic characteristics during hull deformation, this embodiment uses a 230,000-ton bulk carrier as the initial hull type for simulation verification. The accuracy of hydrostatic parameter prediction, calculation efficiency, and constraint condition satisfaction are tested under small-amplitude, medium-amplitude, and large-amplitude interactive hull deformation conditions.

[0074] The verification process used the traditional complete hydrostatic calculation method as a reference, and adopted displacement deviation, buoyancy center position deviation and calculation time as the main evaluation indicators. The constraints were set as follows: displacement deviation not exceeding 2%, buoyancy center longitudinal position deviation not exceeding 1% of ship length, and stability-related parameters within the allowable range of the specification.

[0075] Test results show that the method of this invention has a hydrostatic parameter estimation error of less than 0.5% under small deformation conditions, less than 1.5% under medium deformation conditions, and can automatically trigger accurate calculations to ensure an error of less than 0.1% under large deformation conditions, thus meeting the accuracy requirements of ship engineering design. In terms of computational efficiency, traditional complete hydrostatic calculations take approximately 3 to 8 seconds per run, while the method of this invention takes less than 10 milliseconds per estimation, improving computational efficiency by more than 300 times and enabling real-time feedback during the interactive deformation process of the hull. Furthermore, under preset hydrostatic constraints, using the method of this invention for hull deformation editing ensures that the hull shape meets the constraint requirements throughout the entire process, effectively avoiding the constraint overshooting problem that easily occurs in interactive design using traditional methods, and significantly improving the reliability and efficiency of parametric hull design.

[0076] In particular, in some preferred embodiments of the present invention, a computer device is also provided, including a memory and a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method for rapid prediction of hydrostatic characteristics during hull geometric deformation based on sensitivity analysis and free-form deformation coupling described in any of the above embodiments.

[0077] In some other preferred embodiments of the present invention, a computer-readable storage medium is also provided, on which a computer program / instruction is stored, wherein when the computer program is executed by a processor, the steps of the method for rapid prediction of hydrostatic characteristics during hull geometric deformation based on sensitivity analysis and free-form deformation coupling described in any of the above embodiments are implemented.

[0078] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above embodiments of the method for rapid prediction of hydrostatic characteristics during hull geometric deformation based on sensitivity analysis and free-form deformation coupling, which will not be repeated here.

[0079] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0080] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0081] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A method for fast prediction of hydrostatic characteristics during geometric deformation of a ship hull, characterized in that, Includes the following steps: Calculate the initial hydrostatic parameters based on the initial three-dimensional geometric model of the hull; The initial three-dimensional geometric model of the hull is discretized into a triangular mesh model. A small perturbation is applied to each mesh vertex, and the sensitivity is calculated using the finite difference method based on the changes in hydrostatic parameters. Among them, the mesh vertices located near the waterline are subjected to a one-sided constrained perturbation strategy. Establish a free-form deformation (FFD) control frame covering the hull model, and determine the mapping relationship between each mesh vertex and the FFD control point after perturbation; Based on the chain rule, the sensitivity of each grid vertex is coupled with the mapping relationship to construct a control point-level sensitivity matrix; During the deformation of the hull under disturbance, the displacement of the FFD control point is obtained, and the changes in hydrostatic parameters are calculated using a multi-precision prediction strategy.

2. The method of claim 1, wherein The hydrostatic parameters include the drainage volume, the center of buoyancy, and the wetted surface area; the drainage volume and the position of the center of buoyancy are calculated using a method based on patch integration.

3. The method for rapid prediction of hydrostatic characteristics during hull geometric deformation according to claim 1, characterized in that, The sensitivity is calculated as follows: in, For the first The unit displacement of the first grid vertex causes the first... Rate of change of hydrostatic parameters; For the first One hydrostatic parameter; For the first The coordinates of each grid vertex; For the first The tiny perturbation increment of each grid vertex , This refers to the length of the ship's hull.

4. The method for rapid prediction of hydrostatic characteristics during hull geometric deformation according to claim 1, characterized in that, The grid vertices near the waterline The axis coordinate is less than the preset distance The axis coordinates of the grid vertices within; the preset distance The perturbation frequency is 0.5% to 5% of the ship's draft T. The single-sided confined perturbation strategy is as follows: For grid vertices near the waterline below the waterline, a perturbation is applied in the direction pointing towards the inside of the ship, with the perturbation direction being positive; for grid vertices near the waterline above the waterline, a perturbation is applied in the direction towards the air domain, with the perturbation direction being positive. When the disturbance direction is positive, the forward difference scheme is as follows: 。 5. The method for rapid prediction of hydrostatic characteristics during hull geometric deformation according to claim 1, characterized in that, The FFD control frame is sized to completely enclose the hull and expands outward by 2% to 10% of the hull length in each direction, and the control points are arranged in a regular network.

6. The method for rapid prediction of hydrostatic characteristics during hull geometric deformation according to claim 1, characterized in that, The geometric mapping relationship between each grid vertex of the perturbed triangular mesh model and the FFD control points is as follows: in, For the first time after adding perturbation The coordinates of each grid vertex; For the first Coordinates of one FFD control point; These are the weighting coefficients; It is a Bernstein polynomial; , , The order of the FFD in each direction; , , FFD parameter space , , The control point indices in the direction have the following value ranges: , , ; Let be the coordinates of the vertex in the parameter space.

7. The method for rapid prediction of hydrostatic characteristics during hull geometric deformation according to claim 1, characterized in that, The sensitivity of each grid vertex and the mapping relationship between each grid vertex and the FFD control point after perturbation are coupled into a control point level sensitivity; The control point level sensitivity matrix for: Among them, matrix elements For the first The displacement of the FFD control point affects the first... Sensitivity of a hydrostatic parameter.

8. The method for rapid prediction of hydrostatic characteristics during hull geometric deformation according to claim 1, characterized in that, Based on displacement amplitude A multi-precision prediction strategy is used to calculate hydrostatic parameters; when When using a linear model: , The displacement of the FFD control point during the application of the disturbance; when At that time, a response surface model containing second-order terms is adopted: The second-order response matrix The results were obtained by fitting using the response surface methodology, specifically: first, several groups satisfying the following conditions were selected. Control point displacement samples For each sample group, the complete hydrostatic force is calculated using the wetted surface numerical integration method corresponding to the updated triangular network model with added perturbation, and the corresponding hydrostatic parameter changes are obtained. ; Given the sensitivity matrix Based on this, the following second-order polynomial approximation model is constructed. The corresponding samples of each group , , Substitute the values ​​into the approximate model and fit the coefficients of the second-order terms in the approximate model using the least squares method; The complete hydrostatic calculation is substituted into the second-order polynomial approximation model for synchronization. and renew.

9. The method for rapid prediction of hydrostatic characteristics during hull geometric deformation according to claim 8, characterized in that, The threshold and Determined based on error control criteria; when the linear model prediction error is less than 1%, the corresponding displacement amplitude... for When the second-order model prediction error is less than 3%, the corresponding displacement amplitude is... for The error was obtained by comparing the complete calculation results.

10. 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 as described in any one of claims 1 to 9.

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