Real-time simulation method for ice collision fracture of icebreaker based on impact propagation driving

Abstract

The application relates to the field of ship technology and is an ice collision fracture real-time simulation method based on impact propagation driving in an ice area, which comprises the following steps: reading a high-resolution triangular surface grid of sea ice, constructing a low-resolution envelope grid completely surrounding the original surface; tetrahedralizing the envelope grid to generate a volume grid; generating a candidate block in the volume grid space and establishing a mapping relationship between the volume grid and the candidate block; constructing a quality matrix and a discrete Laplace operator based on the volume grid to calculate an explicit propagation mapping; obtaining a collision point, an impact direction and a fracture threshold to construct a local impact source; performing fracture judgment according to the response difference between adjacent candidate blocks and performing connected component analysis on the candidate block adjacency graph; obtaining fragments according to the connected component analysis and updating and displaying the fragment results in real time to realize real-time simulation of ship-ice collision. The application realizes real-time simulation of sea ice fracture in the process of ship-ice collision and improves the realism of the ice area navigation module in a marine simulator.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding technology, and in particular to a real-time simulation method for ship-ice collision fracture in ice zones based on impact propagation. Background Technology

[0002] With the increasing navigability of the Arctic shipping routes and the rise in polar shipping, resource development, and polar operations, higher demands are being placed on maritime simulators for ice-covered navigation safety training, navigation risk assessment, and verification of polar operation plans. Ice-covered navigation scenarios are characterized by strong nonlinearity, strong coupling, and multi-scale features. The interaction between ships and sea ice involves complex processes such as contact impact, energy propagation, material failure, and debris movement. Real-time sea ice fracture simulation has become a key issue affecting the realism and interactivity of ice-covered navigation simulations.

[0003] Traditional physics-based fracture simulation methods typically rely on continuum mechanics, finite element methods, mass-spring models, or meshless methods. These methods offer high physical accuracy in stress-strain representation and fracture mechanism description, but they often require solving large sparse linear systems and involve dynamic mesh reconstruction or topology updates, resulting in high computational costs and making them difficult to apply directly to real-time interactive environments such as nautical simulators.

[0004] Geometrically driven and pre-fragmentation methods typically utilize Voronoi partitioning, recursive space partitioning, or predefined fragmentation patterns to generate fracture effects, offering high operational efficiency and suitability for real-time display. However, these methods primarily rely on preset geometric rules for fracture patterns, lacking modeling of impact propagation, energy diffusion, and relative motion trends of adjacent ice blocks during ship-ice collisions. This can easily lead to problems such as strong randomness in fracture results, insufficient physical consistency, and unclear impact location responses.

[0005] The existing technology still has the following problems:

[0006] (1) The high-precision physical fracture method has a large computational load, which makes it difficult to meet the real-time interaction requirements; (2) The pure geometric pre-fracture method lacks the expression of impact propagation and energy consistency, and the physical interpretability of the fracture results is insufficient; (3) Directly involving high-resolution sea ice surface meshes in fracture calculations leads to complex topology processing and increased communication and rendering overhead; (4) The collision detection, fracture solution and visualization update in the ship-ice interaction simulation system are highly coupled, which is not conducive to expansion and deployment.

[0007] Therefore, there is a need to provide a method that can improve the real-time performance and rationality of ship-ice interaction and breaking simulation in the ice zone in a navigation simulator while maintaining consistency in sea ice fracture morphology, impact propagation process and visualization details. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a real-time simulation method for ship-ice collision fracture in ice-covered areas based on impact propagation. This invention achieves real-time simulation of sea ice fracture during ship-ice collisions through surface decoupling modeling, mass-weighted impact propagation, candidate block-level fracture determination, and a pre-computation acceleration strategy, thereby improving the realism and immersion of the ice-covered navigation module in a maritime simulator.

[0009] The technical means employed in this invention are as follows: A real-time simulation method for ship-ice collision fracture in ice-covered areas based on impact propagation includes: reading a high-resolution triangular surface mesh of sea ice and constructing a low-resolution envelope mesh that completely surrounds the original surface; tetrahedronizing the envelope mesh to generate a volume mesh; generating candidate blocks in the volume mesh space and establishing a mapping relationship between the volume mesh and the candidate blocks; constructing a mass matrix and a discrete Laplacian operator based on the volume mesh to calculate the explicit propagation mapping; obtaining the collision point, impact direction, and fracture threshold to construct a local impact source; performing fracture determination based on the response differences between adjacent candidate blocks and performing connectivity component analysis on the adjacency graph of the candidate blocks; obtaining fragments based on the connectivity component analysis and updating and displaying the fragment results in real time to achieve real-time simulation of ship-ice collision.

[0010] Furthermore, by reading the high-resolution triangular surface mesh of the sea ice, a vertex set and a face set are obtained, and the vertex coordinates are normalized to the range of a unit cube; an unsigned distance field is constructed based on the original surface vertex set. ,in For spatial points, express Find the shortest distance to the original surface; define the offset isosurface and determine the offset distance through binary search so that the offset surface completely surrounds the original surface, closely approximates the original geometry and does not intersect; extract the offset surface using the MarchingCubes algorithm and simplify the mesh using the QEM edge collapse method; perform Boolean union operation to obtain a low-resolution envelope mesh.

[0011] Furthermore, the envelope mesh is subjected to Delaunay tetrahedral subdivision to generate a volume mesh and a set of nodes. and tetrahedral unit set During the partitioning process, the mass of the control unit is constrained by the minimum shape ratio.

[0012] Furthermore, Voronoi seed points are arranged in the volume mesh space, and tetrahedral elements are divided into different candidate blocks according to spatial proximity; let the set of candidate blocks be... Each candidate block consists of a set of adjacent tetrahedral units, and a tetrahedral adjacency matrix is ​​constructed based on the shared face relationships of the tetrahedrons. Construct a mapping matrix between units and candidate blocks based on the tetrahedral belonging candidate block relationship. ;based on and Further, the candidate block adjacency matrix is ​​obtained. For each candidate block, extract the boundary triangular facets containing tetrahedral units to form a coarse-grained closed boundary; perform a geometric intersection operation between the coarse-grained closed boundary and the original high-resolution surface mesh to obtain the fine surface fragments corresponding to the candidate block.

[0013] Furthermore, the quality matrix constructed based on the volume mesh... and Discrete Laplace operator Specifically, this includes: for an initial shock field The global impulse response after propagation is calculated using a single-step implicit propagation model. :

[0014] in, To propagate step length; Explicit propagation mappings are computed during the preprocessing stage:

[0015] in, This is an explicit propagation mapping.

[0016] Furthermore, the construction of the local impact source specifically includes: when the Unity physics system detects contact between the ship and sea ice, acquiring the collision point. and direction of impact Based on the vertices of the volume mesh Distance to the collision point is used to assign impact weights ,Will Along the direction of impact Extended to vector impulse Obtain the initial impact field The initial impact field includes information on the collision location and impact direction.

[0017] Furthermore, the fracture determination includes: based on the global impact response. The tetrahedral elements or vertex responses are aggregated to the candidate block level according to their quality weights. For adjacent candidate blocks... and Calculate response differences ;when Greater than the fracture threshold If two candidate blocks are considered to have a clear relative motion trend, the corresponding edge in the candidate block's adjacency graph is deleted; otherwise, the connection is maintained. After all adjacent blocks are determined, connected component analysis is performed on the candidate block's adjacency graph. Each connected component represents a piece of sea ice that remains connected as a whole after the impact.

[0018] Furthermore, based on the results of the connected component analysis, fragment labels or OBJ fragment data are generated and returned to the Unity client. The Unity client hides the rendering and collision components of the impacted object, allowing the fragments to participate in rigid body motion in the scene and be visualized.

[0019] Compared with the prior art, the present invention has the following advantages: This invention moves the low-resolution volume mesh construction, candidate block partitioning, adjacency relationship establishment, high-resolution surface fragment generation, and impact propagation matrix solution to the preprocessing stage. During the runtime stage, only impact source construction, matrix-vector multiplication, block-level fracture determination, and connected component analysis are performed, which significantly reduces real-time computational overhead.

[0020] This invention describes the propagation of impact in sea ice medium using a mass-weighted propagation operator and a discrete Laplace operator, making the fracture results related to the collision point, impact direction, propagation step size, and grid topology. Compared with random geometric fragmentation, it can better reflect the energy propagation and fragment separation mechanism in ship-ice collisions.

[0021] This invention employs a decoupled representation of the volume and surface, where a low-resolution volume mesh undertakes the physical calculations and a high-resolution surface mesh undertakes the final display. This avoids the high-resolution mesh from participating in real-time fracture calculations while preserving the geometric details of the sea ice surface.

[0022] This invention adopts a client-server separation architecture. The Unity client is responsible for collision detection and visualization updates, while the server is responsible for complex geometric calculations, impact propagation, and fragment generation, which facilitates the expansion of multi-level fragmentation, remote calculation, and deployment on different simulation platforms.

[0023] This invention limits the fragmentation level by using a hierarchical object control method, avoiding infinite recursive fragmentation and improving system stability in continuous collision scenarios. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the real-time simulation method for ship-ice collision fracture in ice zones based on impact propagation driven by the present invention.

[0026] Figure 2 This is a schematic diagram of a high-resolution sea ice model in an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of the d-isosurface of the sea ice model in an embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram of Matchingcube in an embodiment of the present invention.

[0029] Figure 5 This is a schematic diagram of low-resolution envelope surface generation in an embodiment of the present invention.

[0030] Figure 6 This is a schematic diagram of the intersection operation results of the volume mesh and the high-resolution surface mesh in an embodiment of the present invention.

[0031] Figure 7 This is a cloud map of a local impact source in an embodiment of the present invention.

[0032] Figure 8 This is a schematic diagram of the global impact response in an embodiment of the present invention.

[0033] Figure 9 This is a schematic diagram of a ship-ice interaction scenario in an embodiment of the present invention.

[0034] Figure 10 This is a schematic diagram showing the relationship between the fracture pattern and the impact location in an embodiment of the present invention.

[0035] Figure 11 This is a schematic diagram showing the relationship between the fracture morphology and the fracture threshold in an embodiment of the present invention.

[0036] Figure 12 This is a schematic diagram of large-scale scene interaction in an embodiment of the present invention. Detailed Implementation

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0040] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0041] like Figure 1 As shown, this invention provides a real-time simulation method for ship-ice collision fracture in ice-covered areas based on impact propagation, including: reading a high-resolution triangular surface mesh of sea ice and constructing a low-resolution envelope mesh that completely surrounds the original surface; in a preferred embodiment of this invention, by reading the high-resolution triangular surface mesh of sea ice, a vertex set and a face set are obtained, such as... Figure 2 To improve the stability of subsequent calculations, the vertex coordinates are normalized to the range of a unit cube, enabling envelope generation, tetrahedralization, and impact propagation calculations to be performed on models of different sizes at a uniform scale.

[0042] Construct an unsigned distance field based on the original surface vertex set. ,in For spatial points, express The shortest distance to the original surface; define the offset isosurface, such as Figure 3 As shown, the offset distance is determined through binary search, ensuring that the offset surface completely surrounds the original surface, closely approximating the original geometry without intersecting. The Marching Cubes algorithm is then used to extract the offset surface, as shown below. Figure 4 The mesh is simplified using the QEM edge collapse method. To avoid self-intersections or duplicated faces during the simplification process, Boolean union operations can be performed to obtain a low-resolution cage mesh, such as... Figure 5 As shown.

[0043] The envelope mesh is tetrahedralized to generate a volume mesh; in a preferred embodiment of the invention, the envelope mesh is subjected to Delaunay tetrahedral subdivision to generate a volume mesh and a set of nodes. and tetrahedral unit set During the meshing process, the mass of the control unit is constrained by the minimum shape ratio to avoid excessively flat or distorted tetrahedrons affecting the stability of the discrete Laplacian operator. The volume mesh is not directly used for the final display, but is used for impact propagation, candidate block division, and fracture determination.

[0044] Candidate blocks are generated in the volume mesh space, and a mapping relationship between the volume mesh and the candidate blocks is established. In a preferred embodiment of the invention, Voronoi seed points are arranged in the volume mesh space, and tetrahedral elements are divided into different candidate blocks according to spatial proximity. Let the set of candidate blocks be... Each candidate block consists of a set of adjacent tetrahedral units, and a tetrahedral adjacency matrix is ​​constructed based on the shared face relationships of the tetrahedrons. Construct a mapping matrix between units and candidate blocks based on the tetrahedral belonging candidate block relationship. ;based on and Further, the candidate block adjacency matrix is ​​obtained. During the runtime phase, only the candidate block adjacency graph needs to be analyzed. Remove the edges and perform connected component analysis.

[0045] For each candidate block, boundary triangular patches containing tetrahedral elements are extracted to form a coarse-grained closed boundary. The coarse-grained closed boundary is then geometrically intersected with the original high-resolution surface mesh to obtain the fine-grained surface fragments corresponding to the candidate block. For example... Figure 6 As shown, this process is completed in one go during the preprocessing stage, and during runtime, only the corresponding fine fragments are output based on the fracture labels of the candidate blocks, thereby avoiding the participation of high-resolution surface meshes in real-time fracture calculations.

[0046] The explicit propagation map is calculated by constructing a mass matrix and a discrete Laplacian operator based on a volume mesh; in a preferred embodiment of the invention, the mass matrix is ​​constructed based on a volume mesh. and Discrete Laplace operator Specifically, it includes: For an initial shock field The global impulse response after propagation is calculated using a single-step implicit propagation model. :

[0047] in, To propagate step length; To meet the requirements of real-time simulation, explicit propagation mappings are calculated during the preprocessing stage:

[0048] in, This is an explicit propagation mapping. Only execution is required during the runtime phase. The global shock response field can then be obtained.

[0049] The collision point, impact direction, and fracture threshold are obtained to construct a local impact source. In a preferred embodiment of this invention, when the Unity physics system detects contact between a ship and sea ice, the collision point is obtained. and direction of impact Based on the vertices of the volume mesh Distance to the collision point is used to assign impact weights The weights can be calculated using a linear decay function, a Gaussian decay function, or a compact support kernel function. Along the direction of impact Extended to vector impulse Obtain the initial impact field The initial impact field contains information about the collision location and impact direction, so different collision conditions will lead to different fracture responses.

[0050] Fragmentation determination is performed based on the response differences between adjacent candidate blocks, and connectivity component analysis is performed on the candidate block adjacency graph; in a preferred embodiment of the present invention, based on the global impulse response... The tetrahedral elements or vertex responses are aggregated to the candidate block level according to their quality weights. For adjacent candidate blocks... and Calculate response differences ;when Greater than the fracture threshold If two candidate blocks are considered to have a clear relative motion trend, the corresponding edge in the candidate block's adjacency graph is deleted; otherwise, the connection is maintained. After all adjacent blocks are determined, connected component analysis is performed on the candidate block's adjacency graph. Each connected component represents a piece of sea ice that remains connected as a whole after the impact.

[0051] Fragments are obtained based on connected component analysis, and the fragment results are updated and displayed in real time to achieve real-time simulation of ship-ice collision. In a preferred embodiment of this invention, fragment labels or OBJ fragment data are generated based on the connected component analysis results and returned to the Unity client. The client hides the rendering and collision components of the impacted object, parses the returned fragment results, creates a new Mesh object, and adds Renderer, Collider, and Rigidbody components to it, allowing the fragments to continue participating in visualization and rigid body motion within the scene.

[0052] Example 1 To address the challenge of maintaining real-time performance, physical plausibility, and high-resolution visualization details in existing ice-sea collision fracture simulations, this invention provides a real-time simulation method and system for ice-sea collision fracture based on impact propagation. By employing surface decoupling modeling, mass-weighted impact propagation, candidate block-level fracture determination, and pre-computation acceleration strategies, the method achieves real-time simulation of sea ice fracture during ship-ice collisions, thereby enhancing the realism and immersion of the ice navigation module in a navigation simulator.

[0053] This invention provides a real-time simulation method for ship-ice collision fracture in ice-covered areas based on impact propagation, comprising the following steps: Decoupled modeling of sea ice surface: Read the high-resolution triangular surface mesh of sea ice and normalize the vertices; construct a low-resolution envelope mesh that completely surrounds the original surface; tetrahedronize the envelope mesh to generate a low-resolution volume mesh for impact propagation and fracture determination.

[0054] Candidate block and multi-level mapping preprocessing: Candidate blocks are generated in the low-resolution volume mesh space based on Voronoi partitioning; forward aggregation mapping and reverse display mapping are established between volume mesh vertices, tetrahedral elements, candidate blocks and fine surface fragments; candidate block adjacency graph is constructed based on tetrahedral shared face relationships.

[0055] Impact propagation pre-computation: Based on the volume mesh, a mass matrix and a discrete Laplace propagation operator are constructed, and the implicit impact propagation equation is transformed into an explicit mapping matrix, so that the high-dimensional linear system does not need to be solved repeatedly during the running phase.

[0056] Runtime local impact construction: When a ship collides with sea ice, the collision point, impact direction and fracture threshold are obtained, a local impact source is constructed in the neighborhood of the collision point, and the impact weight is extended along the impact direction to form the initial impact field.

[0057] Impact response and fracture determination: The initial impact field is diffused into a global impact response field using a pre-computed explicit mapping matrix; the response is aggregated to the candidate block level; adjacent edges of candidate blocks are deleted or retained based on the comparison results of the response differences between adjacent candidate blocks and the fracture threshold, and the fragment set is obtained through connected component analysis.

[0058] Real-time visualization: Candidate block-level fracture labels are mapped back to high-resolution surface fragments. The client generates mesh objects, rendering components, collision components, and rigid body components based on the fragment labels or OBJ fragment data returned by the server, realizing real-time display of the ship-ice collision and breaking process.

[0059] The present invention also provides a real-time simulation system for ship-ice collision fracture in ice zones based on impact propagation, including a mesh preprocessing module, a body surface decoupling mapping module, an impact propagation pre-calculation module, a real-time fracture calculation module, a communication interaction module, and a visualization display module.

[0060] The mesh preprocessing module is used to read the input sea ice surface mesh, perform normalization, construct a low-resolution envelope mesh, and generate a tetrahedral volume mesh.

[0061] The volume surface decoupling mapping module is used to establish the mapping relationship between volume mesh vertices, tetrahedral elements, candidate blocks, and high-resolution surface fragments, thereby decoupling physical calculations from the final display.

[0062] The shock propagation pre-computation module is used to construct the mass matrix, discrete Laplacian operator, and explicit propagation mapping matrix, and to cache candidate block adjacency graphs and fine fragmentation data.

[0063] The real-time fracture calculation module is used to calculate the response differences of candidate blocks based on the collision point, impact direction and fracture threshold, update the adjacency graph of candidate blocks and output the connected component results.

[0064] The communication and interaction module is used to transmit collision events, impact parameters, debris labels, and debris model data between the client and the server.

[0065] The visualization module is used to generate meshes, materials, colliders, and rigid bodies in a Unity scene based on fragment tags or OBJ fragment data, and to drive fragment movement and rendering updates.

[0066] In this embodiment, the system adopts a client-server separation architecture. The client is preferably a Unity environment, used for scene building, ship motion control, collision detection, physical interaction, and visualization updates; the server is preferably a Python program, used for model reading, tetrahedronization, candidate block partitioning, impact propagation pre-calculation, fracture determination, and fragment generation.

[0067] During startup, the server reads the sea ice model and completes normalization, cage construction, tetrahedronization, candidate block partitioning, adjacency graph construction, fine-grained debris pre-generation, and explicit mapping pre-computation of impact propagation. These results are then kept in memory or cached in local files during subsequent interactions, avoiding the repeated execution of costly geometric calculations for each collision event.

[0068] During runtime, the server listens for client requests via TCP sockets. Each collision event is encapsulated as a JSON message, with fields including object_name, point, direction, and threshold. object_name distinguishes whether the collision occurred on a intact object or existing debris; point determines the impact location; direction indicates the impact direction; and threshold controls the degree of fragmentation.

[0069] After the client detects a collision between the ship and the target sea ice object, it first determines whether the object meets the breakup trigger conditions. The system can classify objects into three categories: Root, Fragment_i, and SubFragment_i. Root represents the initial intact sea ice object, Fragment_i represents primary fragments, and SubFragment_i represents secondary fragments. Root and Fragment_i can trigger breakup calculations, while SubFragment_i will not trigger further breakup, thus limiting the recursion level and maintaining system stability.

[0070] After receiving a collision message, the server transforms the collision point to the fragmentation model coordinate system, constructs a local impact source based on the collision point and direction, obtains the global response field through pre-calculated propagation mapping, performs candidate block-level fracture determination and connectivity component analysis, and serializes the corresponding fragment model before returning it to the client. The client receives the data and updates the scene object, enabling real-time display of the ship-ice interaction and fragmentation process.

[0071] Example 2 To verify the stability of the method of this invention, surface decoupling experiments can be conducted on sea ice models of different complexities. As the surface noise intensity increases, the number of vertices and faces of the original surface mesh increases. However, by using low-resolution cages and tetrahedral volume meshes to handle physical calculations, preprocessing can still be completed within an acceptable time, and low computational overhead can be maintained during the runtime phase.

[0072] Table 1 presents the surface decoupling results for sea ice models of different complexities in one embodiment. The results show that as the surface geometric complexity increases, the number of cage meshes and tetrahedral elements grows at a controllable scale, proving that this surface decoupling strategy can adapt to sea ice surface models of different resolutions.

[0073] Table 1 Results of surface decoupling experiments on the sea ice model

[0074] In the impact propagation experiment, a structure was built as follows: Figure 9 In the interactive scenario shown, when the breakage threshold is lowered, adjacent candidate blocks are more easily identified as broken, the number of independent fragments increases, and the breakage range expands, as shown in the example. Figure 10As shown; when the location of the collision point changes, the fracture area spatially shifts and tends to spread from the collision point outwards, as... Figure 11 As shown above, the fracture results of this invention are driven by the collision location, impact direction, propagation step size, fracture threshold, and volume mesh topology, rather than by random geometric segmentation.

[0075] In real-time testing, since volume mesh construction, candidate block partitioning, adjacency relationship establishment, and impact propagation matrix solving are all completed in the preprocessing stage, the runtime stage only needs to perform local impact source construction, matrix-vector multiplication, candidate block response calculation, adjacent edge deletion, and connected component analysis based on the current collision event. Therefore, it can meet the real-time display requirements of ship-ice interaction scenarios in a navigation simulator, and the overall effect is as follows: Figure 12 As shown.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A real-time simulation method for ship-ice collision fracture in ice-covered areas based on impact propagation, characterized in that, include: Read the high-resolution triangular surface mesh of sea ice and construct a low-resolution envelope mesh that completely surrounds the original surface; The envelope mesh is tetrahedralized to generate a volume mesh; Candidate blocks are generated in the volume mesh space, and a mapping relationship between the volume mesh and the candidate blocks is established; Voronoi seed points are arranged in the volume mesh space, and tetrahedral elements are divided into different candidate blocks according to spatial proximity; let the set of candidate blocks be... Each candidate block consists of a set of adjacent tetrahedral units, and a tetrahedral adjacency matrix is ​​constructed based on the shared face relationships of the tetrahedrons. Construct a mapping matrix between units and candidate blocks based on the tetrahedral belonging candidate block relationship. ;based on and Further, the candidate block adjacency matrix is ​​obtained. ; For each candidate block, extract the boundary triangular facets containing tetrahedral units to form a coarse-grained closed boundary; perform a geometric intersection operation between the coarse-grained closed boundary and the original high-resolution surface mesh to obtain the fine surface fragments corresponding to the candidate block; The explicit propagation map is calculated by constructing a mass matrix and a discrete Laplacian operator based on a volume mesh; specifically, the construction of the mass matrix and discrete Laplacian operator based on the volume mesh includes: For an initial shock field The global impulse response after propagation is calculated using a single-step implicit propagation model. : in, To propagate step length; Represents the mass matrix, Represents the discrete Laplace operator; Explicit propagation mappings are computed during the preprocessing stage: in, For explicit propagation mapping; Obtain the collision point, impact direction, and fracture threshold to construct a local impact source; Breakage determination is performed based on the response differences between adjacent candidate blocks, and connectivity component analysis is conducted on the candidate block adjacency graph; the breakage determination includes: Based on global shock response The tetrahedral elements or vertex responses are aggregated to the candidate block level according to their quality weights. For adjacent candidate blocks... and Calculate response differences ;when Greater than the fracture threshold If two candidate blocks are considered to have a clear relative motion trend, the corresponding edge in the candidate block adjacency graph is deleted; otherwise, the connection is maintained. After all adjacent blocks are determined, connected component analysis is performed on the candidate block adjacency graph. Each connected component represents a piece of sea ice that remains connected as a whole after the impact. Based on the analysis of the connected components, fragments are obtained, and the fragment results are updated and displayed in real time to realize real-time simulation of ship-ice collision.

2. The real-time simulation method for ship-ice collision fracture in ice zones based on impact propagation driven according to claim 1, characterized in that, By reading the high-resolution triangular surface mesh of the sea ice, the vertex set and the face set are obtained, and the vertex coordinates are normalized to the range of a unit cube. Construct an unsigned distance field based on the original surface vertex set. ,in For spatial points, express Find the shortest distance to the original surface; define the offset isosurface and determine the offset distance through a binary search, so that the offset surface completely surrounds the original surface, closely follows the original geometry and does not intersect; The offset surface is extracted using the Marching Cubes algorithm, and the mesh is simplified using the QEM edge collapse method; Boolean union operation is performed to obtain a low-resolution envelope mesh.

3. The real-time simulation method for ship-ice collision fracture in ice zones based on impact propagation driven according to claim 1, characterized in that, Perform Delaunay tetrahedral subdivision on the envelope mesh to generate a volume mesh and a set of nodes. and tetrahedral unit set During the partitioning process, the mass of the control unit is constrained by the minimum shape ratio.

4. The real-time simulation method for ship-ice collision fracture in ice zones based on impact propagation driven according to claim 1, characterized in that, The construction of the local impact source specifically includes: When the Unity physics system detects a ship making contact with sea ice, it obtains the collision point. and direction of impact Based on the vertices of the volume mesh Distance to the collision point is used to assign impact weights ,Will Along the direction of impact Extended to vector impulse Obtain the initial impact field The initial impact field includes information on the collision location and impact direction.

5. The real-time simulation method for ship-ice collision fracture in ice zones based on impact propagation driven according to claim 1, characterized in that, Based on the results of the connected component analysis, fragment labels or OBJ fragment data are generated and returned to the Unity client. The Unity client hides the rendering and collision components of the impacted object, allowing the fragments to participate in rigid body motion in the scene and be visualized.

Images