A method for real-time visual presentation of ship icebreaking process showing sea ice fracture features

Abstract

The application discloses a ship icebreaking process visual presentation method for displaying sea ice splitting characteristics in real time, relates to the technical field of ship simulation, and comprises the following steps: performing numerical simulation on the collision and splitting mechanical behavior of sea ice in the ship sailing process in advance to construct a typical characteristic crack database; determining crack characteristic parameters matched with icebreaking working condition parameters of a simulation scene based on the pre-constructed typical characteristic crack database; and implanting a sea ice crack path in an ice field according to the crack characteristic parameters, so that sea ice units in the crack path can be deleted by triggering the collision of a ship bow in the simulation process, and a visual picture of the splitting of a sea ice model caused by the collision of a ship model can be displayed. The method can display the sea ice splitting process in real time based on data driving, and can meet the visual presentation and real-time requirements of the most common sea ice splitting phenomenon in the ice area sailing of a ship simulation platform.

Description

Technical Field

[0001] This application relates to the field of ship simulation technology, and in particular to a method for visually presenting the ship icebreaking process in real time, showcasing the characteristics of sea ice splitting. Background Technology

[0002] Polar vessels are essential equipment for polar shipping and trade, waterway development and maintenance, and resource exploitation. The harsh polar environment necessitates significant differences in the design of polar vessels compared to conventional ships. Besides excellent open-water navigation performance, polar vessels must also possess superior ice-crossing capabilities, icebreaking performance, and ice-handling capabilities. Currently, the most common ice-crossing operation for polar vessels is continuous icebreaking, which utilizes a special bow structure for continuous icebreaking while maintaining a stable speed. This method is suitable for typical layered ice conditions. Therefore, studying the navigation mechanism of polar vessels under continuous icebreaking mode is beneficial for performance evaluation and hull-type optimization design.

[0003] Conventional methods such as empirical estimation, model testing, or actual ship testing are ineffective. Therefore, current methods generally utilize navigation simulators to simulate the continuous icebreaking process of ships navigating in polar regions, providing a human-based forecasting and evaluation tool for ship navigation performance in ice-covered areas. Research on ice zone visualization in navigation simulators plays an indispensable role in improving their versatility. Ice zone visualization is used to visually represent the process of ships breaking through ice. However, current ice zone visualization primarily relies on visual effects rendering, only roughly showing the breaking effect of ice within the ship's channel. It cannot realistically depict the ice breaking process under stress, leading to an unreasonable representation of the icebreaking process and failing to meet the visual presentation requirements of continuous icebreaking simulation. Summary of the Invention

[0004] This application addresses the aforementioned problems and technical requirements by proposing a method for visually presenting the ship icebreaking process in real time, showcasing the characteristics of sea ice fracturing. The technical solution of this application is as follows:

[0005] A method for visually presenting the ship icebreaking process in real time, showcasing the characteristics of sea ice fracturing, comprising:

[0006] The crack feature parameters corresponding to the icebreaking conditions in the current ship icebreaking simulation scenario are identified in the typical feature crack database as target feature parameters. The typical feature crack database includes the crack feature parameters of sea ice cracks generated under different icebreaking conditions. The typical feature crack database is constructed by numerical simulation of the collision and splitting mechanical behavior of sea ice during ship navigation.

[0007] After randomly implanting crack paths into the sea ice model of the current ship icebreaking simulation scenario according to the target feature parameters, the sea ice model with implanted crack paths is divided into several sea ice units by discrete meshing.

[0008] During the simulation of the current ship icebreaking scenario, when the bow of the ship model collides with the crack initiation point of the crack path implanted in the sea ice model, the sea ice unit in the crack path is deleted to show the visual scene of the sea ice model being split by the collision with the ship model.

[0009] The further technical solution is that each set of crack feature parameters includes the crack propagation morphology and the crack development gap at each location. Crack paths are randomly implanted into the sea ice model of the current ship icebreaking simulation scenario according to the target feature parameters, including:

[0010] In the sea ice model, a crack initiation point is randomly selected. Starting from the crack initiation point, the crack path is formed along a random direction using the crack propagation morphology in the target feature parameters as the path direction and the crack propagation gap at each position in the target feature parameters as the path width.

[0011] A further technical solution is that each set of crack characteristic parameters also includes crack propagation velocity, and the removal of sea ice elements from the crack path includes:

[0012] Based on the crack propagation rate in the target feature parameters, sea ice units in the crack path are deleted sequentially starting from the crack initiation point.

[0013] A further technical solution involves dividing the sea ice model with implanted crack paths into discrete meshes, resulting in several sea ice elements, including:

[0014] The sea ice model outside each crack path is discretized into a discrete mesh using the first discretization method, and the sea ice model inside each crack path is discretized into a discrete mesh using the second discretization method. The mesh density of the second discretization method is higher than that of the first discretization method, and the size of the discrete mesh inside the crack path is smaller.

[0015] The further technical solution is that each set of icebreaking parameters includes sea ice thickness and ship speed, and the visual presentation method of the ship icebreaking process also includes:

[0016] A finite element model of sea ice was constructed based on the measured structural parameters of sea ice and different sea ice thicknesses. The measured structural parameters of sea ice include porosity, elastic modulus and strength.

[0017] Based on the measured constitutive mechanical model of sea ice, the collision and splitting mechanical behavior of sea ice during the ship's navigation at different ship speeds is numerically simulated, and the global cohesive element method in finite element analysis is used to obtain the crack characteristic parameters of sea ice cracks generated under each set of icebreaking conditions.

[0018] Crack characteristic parameters of sea ice cracks generated under different icebreaking conditions were obtained, and a database of typical characteristic cracks was constructed.

[0019] A further technical solution involves obtaining the crack characteristic parameters of sea ice cracks generated under each set of icebreaking conditions, including:

[0020] During the numerical simulation, the crack propagation gaps at various locations of the generated sea ice cracks and the positions of the crack tips at different times are recorded. The crack propagation morphology is obtained by connecting the positions of the crack tips at different times, and the crack propagation rate is calculated based on the positions of the crack tips at different times.

[0021] The further technical solution involves obtaining multiple sets of crack characteristic parameters under each set of icebreaking condition parameters through numerical simulation, determining the crack characteristic parameters corresponding to the icebreaking condition parameters of the current ship icebreaking simulation scenario in the typical characteristic crack database as target characteristic parameters, and embedding crack paths, including:

[0022] Several sets of crack feature parameters are randomly selected from the typical crack feature database and the icebreaking condition parameters corresponding to the current ship icebreaking simulation scenario as target feature parameters. Several crack paths are randomly implanted into the sea ice model according to each set of target feature parameters.

[0023] Further technical solutions include the following methods for visually presenting the ship icebreaking process:

[0024] A crack bounding box is constructed centered on the crack initiation point of each crack path implanted in the sea ice model of the current ship icebreaking simulation scenario. A bow bounding box of the ship model in the current ship icebreaking simulation scenario is also constructed. During the simulation according to the current ship icebreaking simulation scenario, when the overlapping area of ​​the bow bounding box of the ship model and the crack bounding box of a crack path reaches the area threshold, it is determined that the bow of the ship model has collided with the crack initiation point of the crack path.

[0025] A further technical solution is that the shape and size of the crack enclosure box and the bow enclosure box are matched with the icebreaking condition parameters of the current ship icebreaking simulation scenario.

[0026] Further technical solutions include the following methods for visually presenting the ship icebreaking process:

[0027] When a collision is detected between the bow of the ship model and the crack initiation point of the crack path implanted in the sea ice model, triggering the deletion of sea ice units in the crack path, a sea ice splitting sound effect is played synchronously. The further technical solution is as follows.

[0028] The beneficial technical effects of this application are:

[0029] This application discloses a method for real-time visualization of the ship icebreaking process, showcasing the characteristics of sea ice splitting. This method determines crack feature parameters that match the icebreaking conditions of the simulation scenario based on a pre-built database of typical characteristic cracks. Sea ice crack paths are then implanted into the ice field according to these crack feature parameters. During simulation, sea ice units in the crack paths can be deleted by a collision with the ship's bow, thus displaying the visual effect of the sea ice model splitting due to a collision with the ship model. This data-driven method can display the sea ice splitting process in real time, meeting the visual and real-time requirements for the most common sea ice splitting phenomenon during navigation in ice-covered areas in ship simulation platforms. Attached Figure Description

[0030] Figure 1 This is a flowchart of a method for presenting a visual representation of a ship icebreaking process according to an embodiment of this application.

[0031] Figure 2 This is a schematic diagram of a crack path implanted in a sea ice model and the discrete mesh generation in an example. Detailed Implementation

[0032] The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0033] This application discloses a method for visually presenting the ship icebreaking process in real time, showcasing the characteristics of sea ice splitting. Please refer to [reference needed]. Figure 1 The flowchart shown illustrates the method. To demonstrate sea ice splitting characteristics in real-time during simulation, this method first requires numerical simulation of the collision-splitting mechanics of sea ice during ship navigation to obtain crack characteristic parameters of sea ice cracks generated under different icebreaking conditions, thereby constructing a database of typical characteristic cracks. Each set of icebreaking condition parameters includes sea ice thickness and ship speed. The method for constructing the database of typical characteristic cracks through numerical simulation includes:

[0034] (1) A finite element model of sea ice is constructed based on the measured structural parameters and thickness of sea ice, wherein the measured structural parameters of sea ice include the measured porosity, elastic modulus and strength.

[0035] (2) Based on the constructed finite element model of sea ice and the constructed ship model, the collision and splitting mechanical behavior of sea ice during the ship's navigation at the set ship speed is numerically simulated based on the measured constitutive mechanical model of sea ice. The crack characteristic parameters of sea ice cracks generated under the current icebreaking conditions are obtained by using the global cohesive element method in finite element analysis.

[0036] The crack characteristic parameters obtained include: recording the crack propagation gap at various locations of the generated sea ice cracks during the numerical simulation, as well as the position of the crack tip at different times. Then, connecting the positions of the crack tip at different times yields the crack propagation morphology. Therefore, each set of crack characteristic parameters includes the crack propagation morphology and the crack propagation gap at each location. In addition, the crack propagation velocity can be calculated based on the position of the crack tip at different times. Here, the directly calculated crack propagation velocity includes the crack propagation velocity at the crack tip at different locations, or the average crack propagation velocity can be directly calculated to simplify the data.

[0037] In a numerical simulation, sea ice may develop one or more different sea ice cracks. Since the generation of sea ice cracks is random, the crack characteristic parameters of different sea ice cracks are different. In addition, multiple numerical simulations will be carried out under each set of icebreaking conditions to obtain multiple sets of crack characteristic parameters under each set of icebreaking conditions.

[0038] (3) Adjust at least one of sea ice thickness and ship speed to construct different icebreaking condition parameters. Perform full-process numerical simulations under different icebreaking condition parameters to obtain the crack characteristic parameters of sea ice cracks generated under different icebreaking condition parameters, and construct a database of typical characteristic cracks. The obtained numerical simulation results can also be compared and verified with the measured data from Arctic scientific expeditions.

[0039] After pre-constructing a database of typical characteristic cracks, in any simulation process:

[0040] 1. First, construct the current ship icebreaking simulation scenario according to the simulation requirements, including a sea ice model and a ship model. The sea ice model has a predetermined sea ice thickness and can also achieve a snow-covered effect on its surface. Then, determine the crack feature parameters corresponding to the icebreaking condition parameters of the current ship icebreaking simulation scenario in the typical feature crack database as the target feature parameters.

[0041] As shown above, each set of icebreaking condition parameters often corresponds to multiple sets of crack feature parameters. Therefore, this step randomly selects several sets of crack feature parameters from the typical feature crack database and the sets of crack feature parameters corresponding to the icebreaking condition parameters of the current ship icebreaking simulation scenario as target feature parameters.

[0042] 2. Randomly implant crack paths into the sea ice model of the current ship icebreaking simulation scenario according to the target feature parameters. As shown above, each set of crack feature parameters includes the crack propagation morphology, the crack development gap at each location, and the crack propagation velocity. Then, randomly select the crack initiation point in the sea ice model, and then form the corresponding crack path along a random direction from the crack initiation point, using the crack propagation morphology in the target feature parameters as the path direction and the crack development gap at each location in the target feature parameters as the path width.

[0043] 3. The sea ice model with embedded crack paths is discretized into several sea ice units. Mesh discretization can be done using Unity3D's built-in mesh rendering function. Mesh discretization is mainly divided into two categories: discretizing the sea ice model outside each crack path using the first discretization method, and discretizing the sea ice model inside each crack path using the second discretization method. The mesh density of the second discretization method is higher than that of the first discretization method, and the size of the discrete mesh inside the crack path is smaller. For example, in one instance, the coverage area of ​​the entire sea ice model is as follows: Figure 2 As shown by the solid black line in the image, an implanted crack path is as follows: Figure 2 The red solid line in the image shows the sea ice elements obtained by meshing the sea ice model outside the crack path. Figure 2 As shown by the black dashed line in the image, the sea ice elements obtained by meshing the sea ice model inside the crack path are as follows: Figure 2 As shown by the red dashed line in the image.

[0044] 4. During the simulation of the current ship icebreaking simulation scenario, when the bow of the ship model collides with the crack initiation point of the crack path implanted in the sea ice model, the sea ice unit in the crack path is deleted to show the visual scene of the sea ice model being split by the collision with the ship model.

[0045] In one embodiment, collision detection is performed using bounding box theory based on the collision detection principle in Unity3D. After implanting crack paths, a bounding box for cracks is constructed centered on the crack initiation point of each crack path implanted in the sea ice model of the current ship icebreaking simulation scenario, as well as a bounding box for the bow of the ship model in the current ship icebreaking simulation scenario. During the simulation of the current ship icebreaking scenario, when the overlapping area between the bounding box of the ship model's bow and the bounding box of a crack path reaches an area threshold, it is determined that the bow of the ship model has collided with the crack initiation point of the crack path. In one embodiment, the shape and size of the crack bounding box and the bow bounding box are matched with the icebreaking condition parameters of the current ship icebreaking simulation scenario. For example, the higher the ship speed, the larger the bounding box size. This is because a higher ship speed makes it easier for sea ice to split, and a larger bounding box size increases the probability of collision between the two, and a greater distance between them will trigger sea ice splitting.

[0046] As mentioned above, each set of crack feature parameters also includes crack propagation velocity. Therefore, when the bow of the ship model collides with the crack initiation point of the crack path and triggers the deletion of sea ice elements in the crack path, the sea ice elements in the crack path are sequentially deleted from the crack initiation point according to the crack propagation velocity in the target feature parameters. Additionally, when the deletion of sea ice elements in the crack path is triggered, a sea ice splitting sound effect is played simultaneously to further enhance the realism of the visuals.

[0047] The above descriptions are merely preferred embodiments of this application, and this application is not limited to the above embodiments. It is understood that other improvements and variations that can be directly derived or conceived by those skilled in the art without departing from the spirit and concept of this application should be considered to be included within the protection scope of this application.

Claims

1. A method for visually presenting the ship icebreaking process in real time, showcasing the characteristics of sea ice fracturing, characterized in that, The visual presentation method for the ship icebreaking process includes: The crack feature parameters corresponding to the icebreaking conditions in the current ship icebreaking simulation scenario are identified in the typical feature crack database as target feature parameters. The typical feature crack database includes crack feature parameters of sea ice cracks generated under different icebreaking conditions, and the typical feature crack database is constructed by numerical simulation of the collision and splitting mechanical behavior of sea ice during ship navigation. After randomly implanting crack paths into the sea ice model of the current ship icebreaking simulation scenario according to the target feature parameters, the sea ice model with implanted crack paths is divided into several sea ice units by discrete meshing. During the simulation of the current ship icebreaking simulation scenario, when the bow of the ship model collides with the crack initiation point of the crack path implanted in the sea ice model, the sea ice unit in the crack path is deleted to show the visual scene of the sea ice model being split by the collision with the ship model. Each set of crack feature parameters includes the crack propagation morphology and the crack development gap at each location. Randomly implanting crack paths into the sea ice model of the current ship icebreaking simulation scenario according to the target feature parameters includes: randomly selecting a crack initiation point in the sea ice model, and forming a crack path from the crack initiation point along a random direction using the crack propagation morphology in the target feature parameters as the path direction and the crack development gap at each location in the target feature parameters as the path width. Each set of crack feature parameters also includes crack propagation velocity. Deleting sea ice units in the crack path includes: sequentially deleting sea ice units in the crack path starting from the crack initiation point according to the crack propagation velocity in the target feature parameters.

2. The method for visually presenting the ship icebreaking process according to claim 1, characterized in that, The process of discretizing the sea ice model along the implanted crack path into several sea ice elements includes: The sea ice model outside each crack path is discretized into a discrete mesh using the first discretization method, and the sea ice model inside each crack path is discretized into a discrete mesh using the second discretization method. The mesh density of the second discretization method is higher than that of the first discretization method, and the size of the discrete mesh inside the crack path is smaller.

3. The method for visually presenting the ship icebreaking process according to claim 1, characterized in that, Each set of icebreaking parameters includes sea ice thickness and ship speed. The visual presentation method for the ship icebreaking process also includes: A finite element model of sea ice was constructed based on the measured structural parameters of sea ice and different sea ice thicknesses. The measured structural parameters of sea ice include porosity, elastic modulus and strength. Based on the measured constitutive mechanical model of sea ice, the collision and splitting mechanical behavior of sea ice during the ship's navigation at different ship speeds is numerically simulated, and the global cohesive element method in finite element analysis is used to obtain the crack characteristic parameters of sea ice cracks generated under each set of icebreaking conditions. Crack characteristic parameters of sea ice cracks generated under different icebreaking conditions were obtained, and a database of typical characteristic cracks was constructed.

4. The method for visually presenting the ship icebreaking process according to claim 3, characterized in that, The crack characteristic parameters of the sea ice cracks generated under each set of icebreaking conditions include: During the numerical simulation, the crack propagation gaps at various locations of the generated sea ice cracks and the positions of the crack tips at different times are recorded. The crack propagation morphology is obtained by connecting the positions of the crack tips at different times, and the crack propagation rate is calculated based on the positions of the crack tips at different times.

5. The method for visually presenting the ship icebreaking process according to claim 3, characterized in that, Numerical simulation yields multiple sets of crack characteristic parameters under each set of icebreaking conditions. The crack characteristic parameters corresponding to the icebreaking conditions in the current ship icebreaking simulation scenario are determined from the typical characteristic crack database and used as target characteristic parameters. Crack paths are then implanted, including: Several sets of crack feature parameters are randomly selected from the typical crack feature database and the icebreaking condition parameters corresponding to the current ship icebreaking simulation scenario as target feature parameters, and several crack paths are randomly implanted into the sea ice model according to each set of target feature parameters.

6. The method for visually presenting the ship icebreaking process according to claim 1, characterized in that, The method for visually presenting the ship icebreaking process also includes: A crack bounding box is constructed centered on the crack initiation point of each crack path implanted in the sea ice model of the current ship icebreaking simulation scenario. A bow bounding box of the ship model in the current ship icebreaking simulation scenario is also constructed. During the simulation according to the current ship icebreaking simulation scenario, when the overlapping area of ​​the bow bounding box of the ship model and the crack bounding box of a crack path reaches an area threshold, it is determined that the bow of the ship model has collided with the crack initiation point of the crack path.

7. The method for visually presenting the ship icebreaking process according to claim 6, characterized in that, The shapes and dimensions of the crack enclosure and the bow enclosure are matched with the icebreaking parameters of the current ship icebreaking simulation scenario.

8. The method for visually presenting the ship icebreaking process according to claim 1, characterized in that, The method for visually presenting the ship icebreaking process also includes: When a collision is detected between the bow of the ship model and the crack initiation point of the crack path implanted in the sea ice model, triggering the deletion of sea ice units in the crack path, a sea ice splitting sound effect is played synchronously.

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