Ship icebreaking process visual presentation method for displaying sea ice splitting characteristics in real time

Abstract

The invention discloses a ship icebreaking process visual presentation method capable of displaying sea ice splitting characteristics in real time, and relates to the technical field of ship simulation. According to the method, numerical simulation is conducted on collision splitting mechanical behaviors of sea ice in the ship navigation process in advance, and a typical characteristic crack database is constructed; then, crack characteristic parameters matched with the icebreaking working condition parameters of the simulation scene are determined on the basis of a pre-constructed typical characteristic crack database, and a sea ice crack path is implanted into the ice rink according to the crack characteristic parameters, so that sea ice units in the crack path can be triggered and deleted through ship bow collision in the simulation process; and displaying a visual picture that the sea ice model is split due to the collision of the ship model. According to the method, the sea ice splitting process can be displayed in real time based on data driving, and the requirements for visual display and real-time performance of the most common sea ice splitting phenomenon during ice navigation in a ship simulation platform can be met.

Description

Technical Field

[0001] The present application relates to the field of ship simulation technology, and in particular to a method for presenting a visual scene of a ship's icebreaking process that displays sea ice splitting characteristics in real time. Background Art

[0002] Polar navigation ships are necessary equipment for polar shipping and trade, channel development and maintenance, and resource development. The harsh polar environmental conditions make the design of polar navigation ships very different from that of conventional ships. In addition to good open water navigation performance, polar navigation ships must also have good ice navigation performance, excellent icebreaking performance, and ice operation performance. At present, the most commonly used ice navigation condition for polar navigation ships is the continuous icebreaking mode, which is to use the special bow structure to continuously break ice and maintain a stable speed. It is suitable for conventional ice layer conditions. Therefore, studying the navigation mechanism of polar navigation ships in the continuous icebreaking mode is conducive to performance evaluation and ship type optimization design.

[0003] Conventional empirical estimation, model tests or real ship testing methods are not effective. Therefore, at present, the continuous icebreaking process of polar ships is generally simulated through navigation simulators to provide a human-in-the-loop prediction and evaluation method for the navigation performance of ships in ice areas. The study of ice zone vision in navigation simulators plays an indispensable role in improving the versatility of navigation simulators. The ice zone vision is used to visualize the process of ships destroying ice layers. However, the current ice zone vision presentation is mainly based on visual effect rendering, which can only roughly show the crushing effect of ice layers in the ship's channel, and cannot truly show the process of ice layer splitting under force. This will cause the icebreaking process presented by the ice zone vision to be very unreasonable and cannot meet the visual presentation requirements during the simulation of continuous icebreaking of ships. Summary of the invention

[0004] In response to the above problems and technical requirements, this application proposes a visual presentation method for a ship's icebreaking process that displays sea ice splitting characteristics in real time. The technical solution of this application is as follows:

[0005] A method for presenting a visual scene of a ship breaking ice in real time to display sea ice splitting characteristics, the method comprising:

[0006] Determine the crack characteristic parameters in the typical characteristic crack database corresponding to the icebreaking working condition parameters of the current ship icebreaking simulation scene as the target characteristic parameters; the typical characteristic crack database includes the crack characteristic parameters of sea ice cracks generated under different icebreaking working condition parameters, and the typical characteristic crack database is constructed by numerically simulating the collision and splitting mechanical behavior of sea ice during the navigation of the ship;

[0007] After randomly implanting crack paths in the sea ice model of the current ship icebreaking simulation scenario according to the target characteristic parameters, the sea ice model with the implanted crack paths is divided into a number of sea ice units by discrete grids;

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

[0009] A further technical solution is that each set of crack characteristic parameters includes crack propagation morphology and crack expansion gaps at various positions, and crack paths are randomly implanted in the sea ice model of the current ship icebreaking simulation scene according to the target characteristic parameters, including:

[0010] A crack starting point is randomly selected in the sea ice model, and a crack path is formed from the crack starting point along a random direction with the crack extension morphology in the target characteristic parameters as the path direction and the crack expansion gap at each position in the target characteristic parameters as the path width.

[0011] A further technical solution is that each set of crack characteristic parameters also includes crack propagation speed, and deleting the sea ice unit in the crack path includes:

[0012] According to the crack propagation speed in the target characteristic parameter, the sea ice units in the crack path are deleted sequentially starting from the crack starting point of the crack path.

[0013] A further technical solution is to divide the sea ice model with the crack path into a discrete grid and divide it into a number of sea ice units including:

[0014] The sea ice model outside each crack path is discretely meshed according to a first discrete method, and the sea ice model inside each crack path is discretely meshed according to a second discrete method. The mesh density of the second discrete method is higher than that of the first discrete method, and the discrete mesh size inside the crack path is smaller.

[0015] A further technical solution is that each set of icebreaking working condition 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 is 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 mechanics 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 unit method in finite element analysis is used to obtain the crack characteristic parameters of sea ice cracks generated under each set of icebreaking operating parameters.

[0018] The crack characteristic parameters of sea ice cracks generated under different icebreaking operating parameters are obtained and a typical characteristic crack database is constructed.

[0019] A further technical solution is to obtain crack characteristic parameters of sea ice cracks generated under each set of icebreaking working condition parameters, including:

[0020] During the numerical simulation process, the crack expansion gap of the generated sea ice cracks at various locations and the positions of the crack tips of the sea ice cracks at different times are recorded. The positions of the crack tips at different times are connected to obtain the crack propagation morphology, and the crack propagation speed is calculated based on the positions of the crack tips at different times.

[0021] Its further technical solution is to obtain multiple groups of crack characteristic parameters under each group of icebreaking working condition parameters through numerical simulation, determine the crack characteristic parameters corresponding to the icebreaking working condition parameters of the current ship icebreaking simulation scene in the typical characteristic crack database as the target characteristic parameters and implant them into the crack path, including:

[0022] Several groups of crack characteristic parameters are randomly selected from the typical characteristic crack database corresponding to the icebreaking operating parameters of the current ship icebreaking simulation scenario as target characteristic parameters, and several crack paths are randomly implanted in the sea ice model according to each group of target characteristic parameters.

[0023] A further technical solution is that the method for presenting the visual scene of the ship's icebreaking process also includes:

[0024] A crack bounding box is constructed with the crack starting point of each crack path implanted in the sea ice model of the current ship icebreaking simulation scene as the center, and the bow bounding box of the ship model of the current ship icebreaking simulation scene is constructed; during the simulation process according to the current ship icebreaking simulation scene, when it is detected that 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 collides with the crack starting point of the crack path.

[0025] A further technical solution is that the shapes and sizes of the crack bounding box and the bow bounding box are matched with the icebreaking working condition parameters of the current ship icebreaking simulation scene.

[0026] A further technical solution is that the method for presenting the visual scene of the ship's icebreaking process also includes:

[0027] When it is detected that the bow of the ship model collides with the crack starting point of the crack path implanted in the sea ice model and triggers the start of deleting the sea ice units in the crack path, the sea ice splitting sound effect is played synchronously, and a further technical solution is as follows.

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

[0029] The present application discloses a visual presentation method for a ship's icebreaking process that displays the sea ice splitting characteristics in real time. The method determines the crack characteristic parameters that match the icebreaking working condition parameters of the simulation scene based on a pre-built typical characteristic crack database, and implants the sea ice crack path in the ice field according to the crack characteristic parameters, so that the sea ice unit in the crack path can be deleted by triggering the collision of the bow of the ship during the simulation process to display the visual picture of the sea ice model being split by the collision of the ship model. The method can display the sea ice splitting process in real time based on data drive, and can meet the visual display and real-time requirements of the most common sea ice splitting phenomenon when sailing in ice areas in the ship simulation platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a method flow chart of a method for presenting a visual scene of a ship's icebreaking process according to an embodiment of the present application.

[0031] Figure 2 A crack path implanted in the sea ice model and a schematic diagram of the discrete mesh division in an example. DETAILED DESCRIPTION

[0032] The specific implementation of the present application is further described below in conjunction with the accompanying drawings.

[0033] This application discloses a method for presenting a visual scene of a ship breaking ice in real time, which can show the characteristics of sea ice splitting. Figure 1 The method flow diagram shown in the figure shows that in order to display the sea ice splitting characteristics in real time during the simulation process, the method first needs to numerically simulate the collision splitting mechanical behavior of sea ice during the ship's navigation process to obtain the crack characteristic parameters of sea ice cracks generated under different icebreaking conditions, thereby constructing a typical characteristic crack database. Each set of icebreaking conditions parameters includes sea ice thickness and ship speed, and the method of constructing a typical characteristic crack database through numerical simulation includes:

[0034] (1) A finite element model of sea ice is constructed based on the measured structural parameters of sea ice and the thickness of sea ice. 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 occurring when the ship is sailing at the set ship speed is numerically simulated based on the measured constitutive mechanics model of sea ice, and the global cohesive unit method in finite element analysis is used to obtain the crack characteristic parameters of the sea ice cracks generated under the current icebreaking operating parameters.

[0036] The crack characteristic parameters obtained include: recording the crack expansion gap of the generated sea ice cracks at various positions and the position of the crack tip of the sea ice cracks at different times during the numerical simulation process, and then connecting the positions of the crack tips at different times to obtain the crack expansion morphology, so each set of crack characteristic parameters obtained includes the crack expansion morphology and the crack expansion gap at various positions. In addition, the crack expansion speed can also be calculated according to the position of the crack tip at different times. The crack expansion speed directly calculated here includes the crack expansion speed of the crack tip at different positions, or the average crack expansion speed can be directly calculated to simplify the data.

[0037] In a numerical simulation, sea ice may produce 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 performed under each set of icebreaking operating parameters to obtain multiple sets of crack characteristic parameters under each set of icebreaking operating parameters.

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

[0039] After pre-building a typical characteristic crack database, in any simulation process:

[0040] 1. First, the current ship icebreaking simulation scene is constructed according to the simulation requirements, including the sea ice model and the ship model. The sea ice model has a predetermined sea ice thickness, and the snow covering effect can also be achieved on the surface of the sea ice model. Then, the crack characteristic parameters corresponding to the icebreaking working condition parameters of the current ship icebreaking simulation scene in the typical characteristic crack database are determined as the target characteristic parameters.

[0041] As mentioned above, each set of icebreaking operating parameters often corresponds to multiple sets of crack characteristic parameters. In this step, several sets of crack characteristic parameters are randomly selected from the typical characteristic crack database and the sets of crack characteristic parameters corresponding to the icebreaking operating parameters of the current ship icebreaking simulation scene as target characteristic parameters.

[0042] 2. Randomly implant crack paths in the sea ice model of the current ship icebreaking simulation scene according to the target characteristic parameters. As above, each set of crack characteristic parameters includes crack propagation morphology, crack expansion gap at each position, and crack propagation speed. Then, a crack starting point is randomly selected in the sea ice model, and then the corresponding crack path is formed from the crack starting point along the random direction with the crack propagation morphology in the target characteristic parameters as the path direction and the crack expansion gap at each position in the target characteristic parameters as the path width.

[0043] 3. Discrete the sea ice model with the crack path into several sea ice units. The mesh discretization can be completed using the built-in mesh drawing function of Unity3D. Mesh discretization is mainly divided into two categories: the sea ice model outside each crack path is discretized according to the first discretization method, and the sea ice model inside each crack path is discretized according to the second discretization method. The mesh density of the second discretization method is higher than that of the first discretization method, and the discrete mesh size inside the crack path is smaller. For example, in one example, the coverage area of ​​the entire sea ice model is as follows: Figure 2 As shown by the black solid line in the figure, a crack path is implanted as Figure 2 As shown by the red solid line in the figure, the sea ice unit obtained by mesh discretization of the sea ice model outside the crack path is as follows Figure 2 As shown by the black dashed line in , the sea ice unit obtained by mesh discretization of the sea ice model inside the crack path is as follows Figure 2 As shown by the red dashed line in .

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

[0045] In one embodiment, based on the collision detection principle in Unity3D, the bounding box theory is used to perform collision detection. After the crack path is implanted, the crack bounding box can be constructed with the crack starting point of each crack path implanted in the sea ice model of the current ship icebreaking simulation scene as the center, and the bow bounding box of the ship model of the current ship icebreaking simulation scene is constructed. In the simulation process according to the current ship icebreaking simulation scene, when it is detected that 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 collides with the crack starting 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 working condition parameters of the current ship icebreaking simulation scene. For example, the greater the ship speed, the larger the bounding box size. This is because the greater the ship speed, the easier it is to cause sea ice splitting. The larger the bounding box size is set, the greater the probability of collision between the two and the opportunity to trigger sea ice splitting when the distance between the two is far.

[0046] As mentioned above, each set of crack characteristic parameters also includes crack propagation speed. When the bow of the ship model collides with the crack starting point of the crack path and triggers the deletion of the sea ice unit in the crack path, the sea ice units in the crack path are deleted in sequence starting from the crack starting point of the crack path according to the crack propagation speed in the target characteristic parameters. In addition, when the sea ice unit in the crack path is triggered to start deleting, the sea ice splitting sound effect is also played synchronously to further improve the authenticity of the scene.

[0047] The above is only a preferred embodiment of the present application, and the present application is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the protection scope of the present application.

Claims

1. A method for presenting a visual scene of a ship breaking ice in real time to display the characteristics of sea ice splitting, characterized in that: The method for presenting a visual scene of a ship breaking ice comprises: Determine crack characteristic parameters in a typical characteristic crack database corresponding to icebreaking operating parameters of a current ship icebreaking simulation scenario as target characteristic parameters; the typical characteristic crack database includes crack characteristic parameters of sea ice cracks generated under different icebreaking operating parameters, and the typical characteristic crack database is constructed by numerically simulating the collision and splitting mechanical behavior of sea ice during ship navigation; After randomly implanting crack paths in the sea ice model of the current ship icebreaking simulation scene according to the target characteristic parameters, the sea ice model with the implanted crack paths is divided into a plurality of sea ice units by discrete grids; During the simulation process according to the current ship icebreaking simulation scenario, when the bow of the ship model collides with the crack starting point of the crack path implanted in the sea ice model, the sea ice unit in the crack path is triggered to be deleted to display the visual picture of the sea ice model being split by the collision with the ship model.

2. The method for presenting the visual scene of a ship breaking ice according to claim 1 is characterized in that: Each set of crack characteristic parameters includes crack propagation morphology and crack expansion gaps at various positions. The crack paths randomly implanted in the sea ice model of the current ship icebreaking simulation scene according to the target characteristic parameters include: A crack starting point is randomly selected in the sea ice model, and a crack path is formed from the crack starting point along a random direction with the crack extension morphology in the target characteristic parameter as the path direction and the crack expansion gap at each position in the target characteristic parameter as the path width.

3. The method for presenting the visual scene of a ship breaking ice according to claim 2 is characterized in that: Each set of crack characteristic parameters also includes a crack propagation speed, and the deleting of the sea ice unit in the crack path includes: The sea ice units in the crack path are deleted sequentially starting from the crack starting point of the crack path according to the crack propagation speed in the target characteristic parameter.

4. The method for presenting the visual scene of a ship breaking ice according to claim 1, characterized in that: The step of dividing the sea ice model with the crack path embedded therein into a plurality of sea ice units by discrete grids includes: The sea ice model outside each crack path is discretely meshed according to a first discrete method, and the sea ice model inside each crack path is discretely meshed according to a second discrete method. The mesh density of the second discrete method is higher than that of the first discrete method, and the discrete mesh size inside the crack path is smaller.

5. The method for presenting the visual scene of a ship breaking ice according to claim 3 is characterized in that: Each set of icebreaking working condition parameters includes sea ice thickness and ship speed, and the ship icebreaking process visual presentation method further includes: A finite element model of sea ice is 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 mechanics 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 unit method in finite element analysis is used to obtain the crack characteristic parameters of sea ice cracks generated under each set of icebreaking operating parameters. The crack characteristic parameters of sea ice cracks generated under different icebreaking working conditions are obtained and the typical characteristic crack database is constructed.

6. The method for presenting the visual scene of a ship breaking ice according to claim 5 is characterized in that: The crack characteristic parameters of the sea ice cracks generated under each set of icebreaking working condition parameters include: During the numerical simulation process, the crack expansion gap of the generated sea ice cracks at various locations and the positions of the crack tips of the sea ice cracks at different times are recorded. The positions of the crack tips at different times are connected to obtain the crack propagation morphology, and the crack propagation speed is calculated based on the positions of the crack tips at different times.

7. The method for presenting the visual scene of a ship breaking ice according to claim 5, characterized in that: Numerical simulation obtains multiple groups of crack characteristic parameters under each group of icebreaking working condition parameters, and determines the crack characteristic parameters corresponding to the icebreaking working condition parameters of the current ship icebreaking simulation scene in the typical characteristic crack database as the target characteristic parameters and implants them into the crack path, including: Several groups of crack characteristic parameters are randomly selected from each group of crack characteristic parameters corresponding to the icebreaking operating parameters of the current ship icebreaking simulation scene in the typical characteristic crack database as target characteristic parameters, and several crack paths are randomly implanted in the sea ice model according to each group of target characteristic parameters.

8. The method for presenting the visual scene of a ship breaking ice according to claim 1, characterized in that: The method for presenting a visual scene of a ship breaking ice process further comprises: A crack bounding box is constructed with the crack starting point of each crack path implanted in the sea ice model of the current ship icebreaking simulation scene as the center, and a bow bounding box of the ship model of the current ship icebreaking simulation scene is constructed; during the simulation process according to the current ship icebreaking simulation scene, when it is detected that 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 collides with the crack starting point of the crack path.

9. The method for presenting the visual scene of a ship breaking ice according to claim 8, characterized in that: The shapes and sizes of the crack bounding box and the bow bounding box match the icebreaking working condition parameters of the current ship icebreaking simulation scene.

10. The method for presenting the visual scene of a ship breaking ice according to claim 1, characterized in that: The method for presenting a visual scene of a ship breaking ice process further comprises: When it is detected that the bow of the ship model collides with the crack starting point of the crack path implanted in the sea ice model and triggers the start of deleting the sea ice units in the crack path, the sea ice splitting sound effect is played synchronously.

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