Anchor chain simulation method and system based on spring-quality system

Abstract

The invention discloses an anchor chain simulation method and system based on a spring-quality system, and the method comprises the steps: S1, building an anchor chain model, determining the initial position of a first node in the anchor chain model, the length of an anchor chain and the number of nodes, and determining the initial positions of other nodes; s2, applying external force to the anchor chain model, and performing stress analysis on each node in the anchor chain model based on the Newton second law; s3, updating the speed and the position of each node; s4, acquiring an initial distance between adjacent nodes set by a user, comparing the initial distance between the adjacent nodes with a set threshold value, and setting the distance between the adjacent nodes according to a comparison result; and S5, obtaining a simulation result of the anchor chain model. Accurate simulation of the stress and motion state of the anchor chain in a dynamic environment is realized, the simulation accuracy is further improved by setting the distance between adjacent nodes, the dynamic behavior of the anchor chain in the anchoring stage is accurately simulated, and the safety in the ship mooring and operation process is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of anchor chain simulation analysis, and in particular to an anchor chain simulation method and system based on a spring-mass system. Background Art

[0002] In the simulation system, the traditional anchor chain stress analysis method is usually based on the static mechanical model, so it cannot reflect the behavior of the anchor chain in a dynamic environment, especially the dynamic response under the action of external forces such as wind and waves. The limitations of these static methods make it impossible for the ship handling simulator to simulate the stress of the anchor chain during the anchoring stage, resulting in the user being unable to know the state of anchoring, and then in actual ship mooring, potential safety hazards may be caused by anchoring technology. Therefore, there is an urgent need for a simulation technology that can simulate the behavior of anchor chains in real time under dynamic environments. Summary of the invention

[0003] The present invention provides an anchor chain simulation method and system based on a spring-mass system, so as to overcome the technical problem that the existing ship handling simulator cannot simulate the stress condition of the anchor chain of the ship during the anchoring stage, resulting in the user being unable to know the anchoring status, and further, when the ship is actually moored, potential safety hazards may be caused by the anchoring technology.

[0004] In order to achieve the above object, the technical solution of the present invention is:

[0005] A method for simulating an anchor chain based on a spring-mass system, the specific steps comprising:

[0006] S1: establishing an anchor chain model, determining an initial position of a first node in the anchor chain model, a length of the anchor chain, and the number of nodes, and determining initial positions of remaining nodes based on the initial position of the first node, the length of the anchor chain, and the number of nodes;

[0007] S2: Apply external force to the anchor chain model according to the actual environment, and perform force analysis on each node in the anchor chain model based on Newton's second law;

[0008] S3: Update the velocity and position of each node based on the force analysis results of each node;

[0009] S4: obtaining the initial distance between adjacent nodes set by the user, and comparing the initial distance between adjacent nodes with a set threshold, and setting the distance between adjacent nodes according to the comparison result;

[0010] S5: Get the simulation result of the anchor chain model.

[0011] Furthermore, in S1, the calculation formula for the initial positions of the remaining nodes is:

[0012]

[0013] Among them, r anchor_point is the initial position of the first node, that is, the three-dimensional coordinate of the anchor port; p represents other nodes other than the first node, and p∈[1,N-1], N is the number of nodes; L segment is the length between two nodes, and L total is the length of the anchor chain, i.e. the height between the ship and the seabed; is the unit vector of the anchor chain direction.

[0014] Furthermore, in S2, an external force is applied to the anchor chain model with reference to the actual environment, and the process of force analysis of each node in the anchor chain model based on Newton's second law is as follows:

[0015] Initialize the speed of each node as:

[0016] v i (0) = 0

[0017] The total force of each node i in time t is updated, and the update formula is:

[0018]

[0019] Among them, m i is the node quality, is gravity, is the damping force, is the spring force, for other external forces, including reefs and wind;

[0020]

[0021] Where g is the acceleration due to gravity, c is the d is the damping coefficient, x i and x j are the positions of nodes i and j respectively, μ is the friction coefficient; is the natural length of the anchor chain; k ij is the anchor chain stiffness, i, j∈N.

[0022] Furthermore, in S3, the speed and position of each node are updated based on the force analysis result of each node, including:

[0023] The velocity of the node is updated based on the total force on node i. The formula is:

[0024]

[0025] in, is the acceleration of node i, Δt is the time step;

[0026] The position of the node is calculated based on the updated node velocity. The formula is:

[0027] x i (t+Δt)=x i (t)+v i (t)Δt

[0028] Among them, x i (t) is the position of node i at time t, v i (t) is the velocity of node i at time t.

[0029] Furthermore, in S4, the process of obtaining the initial distance between adjacent nodes set by the user, comparing the initial distance between adjacent nodes with the set threshold, and setting the distance between adjacent nodes according to the comparison result is as follows:

[0030] If the distance between adjacent nodes satisfies:

[0031]

[0032] According to the current length of two adjacent nodes Set the distance between adjacent nodes, that is, keep the current length; otherwise, adjust the current length of two adjacent nodes to the set threshold, that is, adjust to

[0033] in, is the current length of two adjacent nodes, C max is the set maximum stretch factor; The natural length of the anchor chain.

[0034] An anchor chain simulation system based on a spring-mass system, used to implement the anchor chain simulation method based on a spring-mass system, comprising:

[0035] Anchor chain model establishment module is used to determine the initial position of the first node, the length of the anchor chain and the number of nodes in the anchor chain model, and determine the initial positions of the remaining nodes based on the initial position of the first node, the length of the anchor chain and the number of nodes;

[0036] Anchor chain model force analysis module, used to perform force analysis on each node in the anchor chain model based on Newton's second law;

[0037] A velocity and position update module, used to update the velocity and position of each node based on the force analysis results of each node;

[0038] The constraint module is used to obtain the initial distance between adjacent nodes set by the user, compare the initial distance between adjacent nodes with the set threshold, and set the distance between adjacent nodes according to the comparison result.

[0039] Furthermore, the anchor chain establishment module determines the calculation formula for the initial positions of the remaining nodes based on the initial position of the first node, the length of the anchor chain and the number of nodes as follows:

[0040]

[0041] Among them, r anchor_point is the initial position of the first node, that is, the three-dimensional coordinate of the anchor port; p represents other nodes other than the first node, and p∈[1,N-1], N is the number of nodes; L segment is the length between two nodes, and L total is the length of the anchor chain, i.e. the height between the ship and the seabed; is the unit vector of the anchor chain direction.

[0042] Furthermore, the process of the anchor chain model force analysis module performing force analysis on each node in the anchor chain model based on Newton's second law is as follows:

[0043] Initialize the speed of each node as:

[0044] v i (0) = 0

[0045] After the anchor chain model is subjected to external force, the total force of each node i within time t is updated, and the update formula is:

[0046]

[0047] Among them, m i is the node quality, is gravity, is the damping force, is the spring force, for other external forces, including reefs and wind;

[0048]

[0049] Where g is the acceleration due to gravity, c is the d is the damping coefficient, x i and x j are the positions of nodes i and j respectively, μ is the friction coefficient; is the natural length of the anchor chain; k ij is the anchor chain stiffness, i, j∈N.

[0050] Furthermore, the speed and position update module updates the speed and position of each node based on the force analysis result of each node, including:

[0051] The velocity of the node is updated based on the total force on node i. The formula is:

[0052]

[0053] in, is the acceleration of node i, Δt is the time step;

[0054] The position of the node is calculated based on the updated node velocity. The formula is:

[0055] x i (t+Δt)=x i (t)+v i (t)Δt

[0056] Among them, x i (t) is the position of node i at time t, v i (t) is the velocity of node i at time t.

[0057] Beneficial effects: The present invention establishes an anchor chain model, and sets the initial position of the first node in the anchor chain model, the length of the anchor chain and the number of nodes; determines the initial positions of the remaining nodes based on the initial position of the first node, the length of the anchor chain and the number of nodes; applies external force to the anchor chain model with reference to the actual environment, and performs force analysis on each node in the anchor chain model; updates the speed and position of each node based on the force analysis result of each node, thereby achieving accurate simulation of the force and motion state of the anchor chain in a dynamic environment; and by setting the distance between adjacent nodes, further improves the simulation accuracy, accurately simulates the dynamic behavior of the anchor chain in the anchoring stage, and improves the safety of the ship during mooring and operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0059] Figure 1 It is a flow chart of an anchor chain simulation method based on a spring-mass system in the present invention;

[0060] Figure 2 Schematic diagram of force analysis of a node in an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] This embodiment provides an anchor chain simulation method based on a spring-mass system. Figure 1 As shown, the specific steps include:

[0063] S1: establishing an anchor chain model, determining an initial position of a first node in the anchor chain model, a length of the anchor chain, and the number of nodes, and determining initial positions of remaining nodes based on the initial position of the first node, the length of the anchor chain, and the number of nodes;

[0064] In a specific embodiment, in S1, the calculation formula for the initial positions of the remaining nodes is:

[0065]

[0066] Among them, r anchor_point is the initial position of the first node, that is, the three-dimensional coordinate of the anchor port; p is the pth node other than the first node, and p∈[1,N-1], N is the number of nodes; L segment is the length between two nodes, and L total is the length of the anchor chain, i.e. the height between the ship and the seabed; is the unit vector of the anchor chain direction.

[0067] Specifically, in this embodiment, the initial anchor chain model is first constructed based on a series of particles (representing the nodes of the anchor chain) and springs (connecting these nodes to simulate the physical properties of the anchor chain). Each particle has position, velocity and mass properties, and each spring has natural length and stiffness properties. The introduction of dynamic physical simulation based on the spring-mass system can effectively improve the simulation accuracy, so that the force and motion state of the anchor chain in a complex dynamic environment can be simulated more realistically. Then, the initial anchor chain model is replaced with a simulated anchor chain model through a three-dimensional model conversion method to make it meet the actual needs in the simulation scene and realize the dynamic visualization of the anchor chain model.

[0068] S2: Perform force analysis on each node in the anchor chain model based on Newton’s second law;

[0069] In a specific embodiment, in S2, the process of performing force analysis on each node in the anchor chain model based on Newton's second law is:

[0070] Initialize the speed of each node as:

[0071] v i (0) = 0

[0072] After the anchor chain model is subjected to external force, the total force of each node i within time t is updated, such as Figure 2 As shown, the update formula is:

[0073]

[0074] Among them, m i is the node quality, is gravity, is the damping force, is the spring force, for other external forces, including reefs and wind;

[0075]

[0076] Where g is the acceleration due to gravity, c is the d is the damping coefficient, x i and x j are the positions of nodes i and j respectively, μ is the friction coefficient; is the natural length of the anchor chain; k ij is the anchor chain stiffness, i, j∈N.

[0077] In this embodiment, the mass of the node is determined according to the material and size of the anchor chain, and the stiffness parameter of the spring can be adjusted according to the actual anchor chain material to meet the simulation requirements under different environmental conditions.

[0078] S3: Update the velocity and position of each node based on the force analysis results of each node;

[0079] In a specific embodiment, in S3, updating the speed and position of each node based on the force analysis result of each node includes:

[0080] The velocity of the node is updated based on the total force on node i. The formula is:

[0081]

[0082] in, is the acceleration of node i, Δt is the time step;

[0083] The position of the node is calculated based on the updated node velocity. The formula is:

[0084] x i (t+Δt)=x i (t)+vi (t)Δt

[0085] Among them, x i (t) is the position of node i at time t, v i (t) is the velocity of node i at time t.

[0086] S4: Obtain the initial distance between adjacent nodes set by the user, compare the initial distance between adjacent nodes with the set threshold, and set the distance between adjacent nodes according to the comparison result; specifically, the user can set the initial distance between adjacent nodes according to the distance of the nodes of the actual anchor chain to meet actual needs.

[0087] In a specific embodiment, in S4, the process of obtaining the initial distance between adjacent nodes set by the user, comparing the initial distance between adjacent nodes with a set threshold, and setting the distance between adjacent nodes according to the comparison result is as follows:

[0088] If the distance between adjacent nodes satisfies:

[0089]

[0090] According to the current length of two adjacent nodes Set the distance between adjacent nodes, otherwise adjust the current length of two adjacent nodes to the set threshold, that is,

[0091] in, is the current length of two adjacent nodes, C max is the set maximum stretch factor; The natural length of the anchor chain.

[0092] Specifically, the distances between the nodes in the anchor chain are detected and adjusted to prevent the anchor chain from being overstretched or compressed. max It can be set according to the actual situation to avoid excessive stretching of the spring, which may lead to inaccurate simulation results.

[0093] S5: Get the simulation result of the anchor chain model.

[0094] Specifically, in this embodiment, the force analysis result of the first node is compared with the set force threshold for completing anchoring. If the force analysis result of the first node meets the set force threshold for completing anchoring, it means that the ship has completed the anchoring process, thereby ensuring the safety of the ship during mooring and operation.

[0095] In this embodiment, an anchor chain simulation system based on a spring-mass system is also provided, which is used to implement the anchor chain simulation method based on a spring-mass system, including:

[0096] Anchor chain establishment model, the anchor chain establishment module is used to determine the initial position of the first node in the anchor chain model, the length of the anchor chain and the number of nodes, and determine the initial positions of the remaining nodes based on the initial position of the first node, the length of the anchor chain and the number of nodes;

[0097] Anchor chain model force analysis module, used to perform force analysis on each node in the anchor chain model based on Newton's second law;

[0098] A velocity and position update module, used to update the velocity and position of each node based on the force analysis results of each node;

[0099] The constraint module is used to obtain the initial distance between adjacent nodes set by the user, compare the initial distance between adjacent nodes with the set threshold, and set the distance between adjacent nodes according to the comparison result.

[0100] Specifically, the anchor chain establishment module determines the calculation formula for the initial positions of the remaining nodes based on the initial position of the first node, the length of the anchor chain and the number of nodes:

[0101]

[0102] Among them, r anchor_point is the initial position of the first node, that is, the three-dimensional coordinate of the anchor port; p represents other nodes other than the first node, and p∈[1,N-1], N is the number of nodes; L segment is the length between two nodes, and L total is the length of the anchor chain, i.e. the height between the ship and the seabed; is the unit vector of the anchor chain direction.

[0103] Specifically, the process of the anchor chain model force analysis module performing force analysis on each node in the anchor chain model based on Newton's second law is as follows:

[0104] Initialize the speed of each node as:

[0105] v i (0) = 0

[0106] After the anchor chain model is subjected to external force, the total force of each node i within time t is updated, and the update formula is:

[0107]

[0108] Among them, m i is the node quality, is gravity, is the damping force, is the spring force, for other external forces, including reefs and wind;

[0109]

[0110]

[0111] Where g is the acceleration due to gravity, c is the d is the damping coefficient, x i and x j are the positions of nodes i and j respectively, μ is the friction coefficient; is the natural length of the anchor chain; k ij is the anchor chain stiffness, i, j∈N.

[0112] Specifically, the speed and position update module updates the speed and position of each node based on the force analysis results of each node, including:

[0113] The velocity of the node is updated based on the total force on node i. The formula is:

[0114]

[0115] in, is the acceleration of node i, Δt is the time step;

[0116] The position of the node is calculated based on the updated node velocity. The formula is:

[0117] x i (t+Δt)=x i (t)+v i (t)Δt

[0118] Among them, x i (t) is the position of node i at time t, v i (t) is the velocity of node i at time t.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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. An anchor chain simulation method based on a spring-mass system, characterized in that: The specific steps include: S1: establishing an anchor chain model, determining an initial position of a first node in the anchor chain model, a length of the anchor chain, and the number of nodes, and determining initial positions of remaining nodes based on the initial position of the first node, the length of the anchor chain, and the number of nodes; S2: Apply external force to the anchor chain model according to the actual environment, and perform force analysis on each node in the anchor chain model based on Newton's second law; S3: Update the velocity and position of each node based on the force analysis results of each node; S4: obtaining the initial distance between adjacent nodes set by the user, and comparing the initial distance between adjacent nodes with a set threshold, and setting the distance between adjacent nodes according to the comparison result; S5: Get the simulation result of the anchor chain model.

2. The anchor chain simulation method based on the spring-mass system according to claim 1 is characterized in that: In S1, the calculation formula for the initial positions of the remaining nodes is: Among them, r anchor_point is the initial position of the first node, that is, the three-dimensional coordinate of the anchor port; p represents other nodes other than the first node, and p∈[1,N-1], N is the number of nodes; L segment is the length between two nodes, and L total is the length of the anchor chain, i.e. the height between the ship and the seabed; is the unit vector of the anchor chain direction.

3. The anchor chain simulation method based on the spring-mass system according to claim 2 is characterized in that: In S2, external force is applied to the anchor chain model with reference to the actual environment, and the process of force analysis of each node in the anchor chain model based on Newton's second law is as follows: Initialize the speed of each node as: v i (0)＝0 The total force of each node i in time t is updated, and the update formula is: Among them, m i is the node quality, is gravity, is the damping force, is the spring force, for other external forces, including reefs and wind; Where g is the acceleration due to gravity, c is the d is the damping coefficient, x i and x j are the positions of nodes i and j respectively, μ is the friction coefficient; is the natural length of the anchor chain; k ij is the anchor chain stiffness, i, j∈N.

4. The anchor chain simulation method based on the spring-mass system according to claim 3 is characterized in that: In S3, the speed and position of each node are updated based on the force analysis results of each node, including: The velocity of the node is updated based on the total force on node i. The formula is: in, is the acceleration of node i, Δt is the time step; The position of the node is calculated based on the updated node velocity. The formula is: x i (t+Δt)=x i (t)+v i (t)Δt Among them, x i (t) is the position of node i at time t, v i (t) is the velocity of node i at time t.

5. The anchor chain simulation method based on the spring-mass system according to claim 4 is characterized in that: In S4, the initial distance between adjacent nodes set by the user is obtained, and the initial distance between adjacent nodes is compared with the set threshold value. The process of setting the distance between adjacent nodes according to the comparison result is as follows: If the distance between adjacent nodes satisfies: According to the current length of two adjacent nodes Set the distance between adjacent nodes, otherwise adjust the current length of two adjacent nodes to the set threshold, that is, in, is the current length of two adjacent nodes, C max is the set maximum stretch factor; The natural length of the anchor chain.

6. An anchor chain simulation system based on a spring-mass system, used to implement the method of claims 1-5, characterized in that: include: Anchor chain establishment model, the anchor chain establishment module is used to determine the initial position of the first node in the anchor chain model, the length of the anchor chain and the number of nodes, and determine the initial positions of the remaining nodes based on the initial position of the first node, the length of the anchor chain and the number of nodes; Anchor chain model force analysis module, used to perform force analysis on each node in the anchor chain model based on Newton's second law; A velocity and position update module, used to update the velocity and position of each node based on the force analysis results of each node; The constraint module is used to obtain the initial distance between adjacent nodes set by the user, compare the initial distance between adjacent nodes with the set threshold, and set the distance between adjacent nodes according to the comparison result.

7. The anchor chain simulation system based on the spring-mass system according to claim 6 is characterized in that: The anchor chain establishment module determines the calculation formula for the initial positions of the remaining nodes based on the initial position of the first node, the length of the anchor chain and the number of nodes: Among them, r anchor_point is the initial position of the first node, that is, the three-dimensional coordinate of the anchor port; p represents other nodes other than the first node, and p∈[1,N-1], N is the number of nodes; L segment is the length between two nodes, and L total is the length of the anchor chain, i.e. the height between the ship and the seabed; is the unit vector of the anchor chain direction.

8. The anchor chain simulation system based on the spring-mass system according to claim 7, characterized in that: The process of the anchor chain model force analysis module to perform force analysis on each node in the anchor chain model based on Newton's second law is as follows: Initialize the speed of each node as: v i (0)＝0 After the anchor chain model is subjected to external force, the total force of each node i within time t is updated, and the update formula is: Among them, m i is the node quality, is gravity, is the damping force, is the spring force, for other external forces, including reefs and wind; Where g is the acceleration due to gravity, c is the d is the damping coefficient, x i and x j are the positions of nodes i and j respectively, μ is the friction coefficient; is the natural length of the anchor chain; k ij is the anchor chain stiffness, i, j∈N.

9. The anchor chain simulation system based on the spring-mass system according to claim 8, characterized in that: The velocity and position update module updates the velocity and position of each node based on the force analysis results of each node, including: The velocity of the node is updated based on the total force on node i. The formula is: in, is the acceleration of node i, Δt is the time step; The position of the node is calculated based on the updated node velocity. The formula is: x i (t+Δt)=x i (t)+v i (t)Δt Among them, x i (t) is the position of node i at time t, v i (t) is the velocity of node i at time t.

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