Parameterized modeling method and system for anchor chain based on multi-body-fluid combined simulation

Abstract

The present application relates to the technical field of marine equipment modeling simulation, and provides an anchor chain parameterized modeling method and system based on multi-body-fluid joint simulation, which comprises: equivalent actual anchor chain to a plurality of anchor chain balls; by means of constant speed towing hydrodynamic simulation, the viscous resistance of the actual anchor chain section is calculated; the same equivalent anchor chain section is simulated under the same towing working condition, and the viscous resistance of the equivalent anchor chain section is calculated; the anchor chain ball radius is corrected through consistency verification; the density of the anchor chain ball is calculated based on the number and radius of the anchor chain ball; the anchoring water depth, mooring radius and seabed lying anchor chain section length of the actual anchor chain are obtained, and the initial position of each anchor chain ball is determined in combination with the anchor chain ball spacing; the model of the seabed and its irregular structures is created, and multi-body-fluid dynamics joint simulation under the action of gravity is carried out in combination with the radius, density and initial position of each anchor chain ball. The problems of low parameterization degree and poor adaptability of the mooring anchor chain lumped mass modeling method are solved.

Description

Technical Field

[0001] This invention belongs to the field of marine engineering equipment modeling and simulation technology, and particularly relates to a parametric modeling method and system for anchor chains based on multibody-fluid co-simulation. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Mooring chains are a key component of marine engineering equipment (such as floating platforms, ships, and offshore wind power facilities). The hydrodynamic characteristics, maximum tension, and strength of the mooring system directly affect the dynamic response characteristics, safety, and stability of floating platforms. Therefore, the dynamic modeling of mooring chains is an unavoidable issue in hydrodynamic analysis of floating marine engineering equipment.

[0004] However, the equivalent simplified model based on potential flow theory reduces the accuracy of hydrodynamic load calculations on mooring chains; simulation models based on computational fluid dynamics struggle to simulate the tensile but not compressive characteristics of anchor chain links, and the large length of the anchor chain and the large-area spatial meshing increase computation time and efficiency. In particular, when the anchor chain system involves seabed reefs or uneven seabed surfaces, traditional lumped mass modeling methods struggle to represent collisions with irregular seabed protrusions, limiting the applicability of this method under complex conditions. Summary of the Invention

[0005] To address the technical problems mentioned above, this invention provides a parametric modeling method and system for anchor chains based on multibody-fluid co-simulation. This method effectively simulates the changes in the anchor chain's position as the mooring float changes, the dynamic changes in the length of the anchor chain lying flat on the seabed, and the collision and contact between the anchor chain and irregular protrusions on the seabed. This improves the calculation accuracy of the hydrodynamic load on the mooring anchor chain and solves the problems of low accuracy and poor adaptability of the lumped mass modeling method for mooring anchor chains.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of this invention provides a parametric modeling method for anchor chains based on multibody-fluid co-simulation, comprising:

[0008] Based on multibody dynamics, the actual anchor chain is equivalent to several anchor chain balls, and the spacing between the anchor chain balls is calculated by combining the total length of the actual anchor chain.

[0009] A particle hydrodynamic tank was created using a semi-implicit moving particle method, and the viscous resistance of the actual anchor chain segment was calculated using constant-speed towing hydrodynamic simulation. Simulations of equivalent anchor chain segments of the same length under the same towing conditions were conducted to calculate the viscous resistance of the equivalent anchor chain segments. The radius of the anchor chain balls was corrected through consistency verification. The density of the anchor chain balls was calculated based on the number and radius of the anchor chain balls. The anchoring depth, mooring radius, and length of the seabed flat anchor chain segment of the actual anchor chain were obtained. Combined with the spacing of the anchor chain balls, the number of anchor chain balls in the seabed flat segment and the suspended segment in the water was determined, and then the initial position of each anchor chain ball was determined.

[0010] A model of the seabed and its irregular structures was created. Based on the radius, density, and initial positions of the anchor chain spheres, a multibody-flow dynamics co-simulation under gravity was performed.

[0011] Furthermore, the number of anchor chain balls in the seabed lying section and the underwater suspended section are respectively: ; ;in, This refers to the number of anchor chain balls on the horizontal section of the seabed. Where d is the number of anchor chain balls suspended in the water, D is the anchoring depth, R is the mooring radius, L is the length of the anchor chain segment lying flat on the seabed, and d is the anchor chain ball length suspended in the water. 间距 The distance between the anchor chain balls.

[0012] Furthermore, the tension characteristics of the anchor chain are expressed using a tensile-resistant but not compressive-resistant equation for adjacent anchor chain balls:

[0013] ;

[0014] in, This represents the actual distance between two adjacent anchor chain balls. K represents the relative speeds of two adjacent anchor chain balls moving towards each other. 刚度 and C 阻尼 These are the spring stiffness coefficient and damping coefficient, d 间距 The distance between the anchor chain balls.

[0015] Furthermore, based on Hertzian contact theory, the contact relationship between the seabed surface and the surface of its irregular structures and the anchor chain ball is defined.

[0016] Furthermore, it also includes: based on the anchor point positions at both ends of the anchor chain and the anchoring water depth, a particle fluid dynamics water tank is created using a semi-implicit moving particle method, and the diameter of the water particles and the calculation step size are determined by combining the diameter and spacing of the anchor chain balls.

[0017] A second aspect of the present invention provides a parametric modeling system for anchor chains based on multibody-fluid co-simulation, comprising:

[0018] The discrete module is configured to: based on multibody dynamics, the actual anchor chain is equivalent to several anchor chain balls, and the spacing between the anchor chain balls is calculated in combination with the total length of the actual anchor chain;

[0019] The calculation module is configured to: create a particle hydrodynamic tank using a semi-implicit moving particle method and calculate the viscous resistance of the actual anchor chain segment using constant-speed towing hydrodynamic simulation; perform simulations under the same towing conditions on equivalent anchor chain segments of the same length and calculate the viscous resistance of the equivalent anchor chain segments; correct the anchor chain ball radius through consistency verification; calculate the anchor chain ball density based on the number and radius of the anchor chain balls; obtain the anchoring depth, mooring radius, and length of the seabed flat anchor chain segment of the actual anchor chain, and determine the number of anchor chain balls in the seabed flat segment and the underwater suspended segment in combination with the anchor chain ball spacing, and then determine the initial position of each anchor chain ball;

[0020] The simulation module is configured to create a model of the seabed and its irregular structures, and perform a multibody-flow dynamics co-simulation under gravity by combining the radius, density and initial position of each anchor chain ball.

[0021] Furthermore, the number of anchor chain balls in the seabed lying section and the underwater suspended section are respectively: ; ;in, This refers to the number of anchor chain balls on the horizontal section of the seabed. Where d is the number of anchor chain balls suspended in the water, D is the anchoring depth, R is the mooring radius, L is the length of the anchor chain segment lying flat on the seabed, and d is the anchor chain ball length suspended in the water. 间距 The distance between the anchor chain balls.

[0022] Furthermore, the tension characteristics of the anchor chain are expressed using a tensile-resistant but not compressive-resistant equation for adjacent anchor chain balls:

[0023] ;

[0024] in, This represents the actual distance between two adjacent anchor chain balls. K represents the relative speeds of two adjacent anchor chain balls moving towards each other. 刚度 and C 阻尼 These are the spring stiffness coefficient and damping coefficient, d 间距 The distance between the anchor chain balls.

[0025] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above-described method for parametric modeling of anchor chains based on multibody-fluid co-simulation.

[0026] A fourth aspect of the present invention provides a computer device including a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor, wherein the processor executes the program to implement the steps in the above-described method for parametric modeling of anchor chains based on multibody-fluid co-simulation.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] This invention equates mooring anchor chains to multiple discrete spheres, with adjacent spheres using tensile but not compressive equations to express the tension characteristics of the anchor chain. Secondly, it utilizes a semi-implicit Lagrange-based moving particle method to create a fluid dynamics model, improving the accuracy of calculating the hydrodynamic loads on the mooring anchor chain. Furthermore, this Lagrange-based method facilitates multibody-fluid dynamics co-simulation, eliminating the need for mesh nesting and improving computational efficiency compared to traditional mesh-based fluid dynamics. Finally, it employs Hertzian contact theory to represent the contact between the spherical anchor chain and the seabed, effectively simulating the changes in the anchor chain's position with the mooring float, the dynamic changes in the length of the anchor chain lying flat on the seabed, and the collision contact between the anchor chain and irregular protrusions on the seabed. This solves the problems of low parameterization and poor adaptability in lumped mass modeling methods for mooring anchor chains.

[0029] This invention equates the actual anchor chain to several anchor chain balls, avoiding the direct use of anchor chain links and anchor chain link contact models, thus greatly improving computational efficiency. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 This is a data processing flowchart of Embodiment 1 of the present invention;

[0032] Figure 2 This is a schematic diagram of the hydrodynamic load equivalent model of Embodiment 1 of the present invention;

[0033] Figure 3 This is a schematic diagram of the hydrodynamic load simulation results of Embodiment 1 of the present invention;

[0034] Figure 4 This is a simplified rigid body model of the lumped mass of the mooring anchor chain according to Embodiment 1 of the present invention;

[0035] Figure 5 This is a schematic diagram of the initial position of the equivalent concentrated mass anchor chain according to Embodiment 1 of the present invention;

[0036] Figure 6 This is a schematic diagram of the catenary configuration under gravity according to Embodiment 1 of the present invention;

[0037] Figure 7 This is a schematic diagram of the contact between the anchor chain ball and the uneven seabed structure in Embodiment 1 of the present invention;

[0038] Figure 8 This is a schematic diagram of the axial force of the anchor chain ball in Embodiment 1 of the present invention;

[0039] Figure 9 This is a fluid dynamics simulation diagram based on the semi-implicit method of moving particles in Embodiment 1 of the present invention;

[0040] Figure 10 This is a schematic diagram of the structure of a computer device according to Embodiment 4 of the present invention. Detailed Implementation

[0041] 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.

[0042] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0043] Example 1

[0044] This embodiment provides a parametric modeling method for anchor chains based on multibody-fluid co-simulation.

[0045] This embodiment provides a parametric modeling method for anchor chains based on multibody-fluid co-simulation. According to the anchor chain linear density and hydrodynamic loads, the mooring anchor chain is equivalent to multiple discrete spheres. The tension characteristics of adjacent spheres are expressed using equations that assess tensile strength but not compressive strength. Furthermore, meshless particle fluid is used to simulate the water environment loads, and the hydrodynamic loads acting on the anchor chain are expressed based on multibody-fluid dynamics co-simulation. Finally, Hertzian contact theory is used to express the contact between the spherical anchor chain and the seabed, effectively simulating the changes in the anchor chain's position with the mooring float, the dynamic changes in the length of the anchor chain lying flat on the seabed, and the collision contact between the anchor chain and irregular protrusions on the seabed. This solves the problems of low parametric degree and poor adaptability in lumped mass modeling methods for mooring anchor chains.

[0046] This embodiment provides a parametric modeling method for mooring anchor chains based on multibody-fluid co-simulation, which inherits the computational advantages of the lumped mass method and significantly improves modeling efficiency and adaptability to complex working conditions, and is of great significance for improving the dynamic modeling and simulation performance of mooring anchor chains.

[0047] This embodiment provides a parametric modeling method for anchor chains based on multibody-fluid co-simulation, such as... Figure 1 As shown, it includes the following steps:

[0048] Step 1: Discretization of anchor chain load equivalent.

[0049] Based on the specifications, length, water depth, and mooring radius of the mooring anchor chain, the mooring anchor chain is discretized into anchor chain ball entities with a certain spacing, and the axial tensile and compressive load relationship between adjacent anchor chain balls is expressed by nonlinear spring force.

[0050] The equivalent parameters of the anchor chain load and the order of calibration of each parameter are as follows: anchor chain length; equivalent hydrodynamic load; equivalent linear density; equivalent tensile stiffness and compressive gap.

[0051] (1) Anchor chain length calibration.

[0052] (101) Obtain the total length L of the actual mooring anchor chain (abbreviated as actual anchor chain, also known as anchor chain link anchor chain). 总长 Based on water depth, estimate the length of the section lying flat on the seabed and the section suspended in the water.

[0053] (102) Based on the total length L 总长 The anchor chain links are discretized into anchor chain balls, which are fewer in number than the anchor chain links, to obtain the equivalent mooring anchor chain (abbreviated as equivalent anchor chain, also known as anchor chain ball anchor chain).

[0054] (103) Based on the total length L 总长 The anchor chain ball spacing d is calculated based on the number of anchor chain balls. 间距 .

[0055] In this embodiment, the anchor chain balls of the same anchor chain specification have equal spacing. Therefore, the number N of anchor chain balls is first determined. 总 Then, the anchor chain ball spacing d is obtained according to formula (1). 间距 :

[0056] (1);

[0057] (2) Hydrodynamic load equivalent.

[0058] (201) First, a hydrodynamic experiment is conducted based on the actual anchor chain specifications. Specifically, a hydrodynamic experiment is conducted on a section of actual anchor chain (the length of this section needs to be greater than or equal to 5 anchor chain ball spacings) to measure the total hydrodynamic load F it experiences in the water flow. 水动力 .

[0059] (202) Then, according to the requirement that the hydrodynamic loads of the actual anchor chain segment and the equivalent anchor chain segment are consistent, the radius r of the equivalent anchor chain ball can be solved. The specific steps are as follows: Create a digital water tank (particle hydrodynamic water tank) based on the semi-implicit moving particle method, carry out constant speed towing hydrodynamic simulation for the actual anchor chain segment of a given length, and calculate the viscous resistance of the actual anchor chain segment; at the same time, carry out towing simulation under the same towing conditions for the equivalent anchor chain segment of the same length, and calculate the viscous resistance of the equivalent anchor chain segment; continuously correct the anchor chain ball radius r so that the two viscous resistances are consistent, and obtain the final equivalent radius r of the anchor chain ball.

[0060] The above equivalence is to obtain the size of the anchor chain ball, that is, to obtain the carrier of hydrodynamic load when the anchor chain moves in the water.

[0061] Among them, the hydrodynamic load is obtained by multibody-particle fluid dynamics co-simulation. Particle fluid dynamics discretizes the fluid into water particles and solves the discrete Navier-Stokes (NS) equations to obtain the final hydrodynamic load. When the anchor chain ball moves in the water, the surrounding liquid water particles will exert viscous drag and inertial drag. This method has a high convergence speed. Combined with parallel computing on a graphics card, it greatly improves the calculation accuracy and speed of the anchor chain hydrodynamic load.

[0062] For example, an anchor chain segment with 11 anchor chain links can be equivalently represented by 6 anchor chain balls, such as... Figure 2 As shown. Following the steps described above, a hydrodynamic experiment was conducted on an actual anchor chain segment to obtain F. 水动力 Then, through hydrodynamic simulation (i.e., multibody-particle hydrodynamic co-simulation), the hydrodynamic loads of the actual anchor chain segment and the equivalent anchor chain segment are calculated and compared, and the anchor chain ball size is continuously adjusted until the hydrodynamic loads are consistent. For example... Figure 3 and Figure 4 As shown, the hydrodynamic loads of the two anchor chain segments are basically the same at this time, and the radius of the anchor chain ball at this time can be used as the final equivalent radius of the anchor chain ball after correction.

[0063] (3) Linear density equivalence. Based on the number of anchor chain balls, the radius of the anchor chain balls, and the total mass of the actual anchor chain (M 锚链 =ρ 线 ×L 总长 , ρ 线 (The actual linear density of the anchor chain) is used to calculate the density of the anchor chain ball.

[0064] Based on the number of anchor chain balls obtained in (1) and the radius of the anchor chain balls obtained in (202), calculate the density of the anchor chain balls, such that the total mass M of the anchor chain is... 锚链 Consistency:

[0065] (2);

[0066] Among them, M 锚链N represents the total mass of the actual anchor chain. 总 This represents the total number of anchor chain balls in the equivalent anchor chain.

[0067] (4) Tensile stiffness is equivalent to compression gap. Based on the axial tensile stiffness of the anchor chain link, the relationship between adjacent anchor chain balls is defined by mechanical equations, resulting in an anchor chain composed of multiple anchor chain balls connected by mechanical equations.

[0068] Because gaps exist between adjacent anchor chain links in actual anchor chains, the anchor chain links move within these gap spaces without being subjected to force. To account for this characteristic, gap control equations and nonlinear spring equations are used. The equivalent anchor chain's tensile and compressive stiffness, as well as the gap distance, are determined. Based on the design specifications for studless anchor chains, the default anchor chain link gap is the anchor chain ball spacing d. 间距 The opposing axial force F between two adjacent anchor chain balls 轴向 The equivalent calculation uses the tensile-resistant but not compressive-resistant equation shown below:

[0069] (3);

[0070] in, The actual distance between two adjacent anchor chain balls is calculated in real time in global coordinates based on the magnitude of the spatial vector of the centroid coordinates of the two balls during simulation (the actual distance between the two anchor chain balls is calculated in real time based on the magnitude of the spatial vector of the centroid coordinates of the two balls). Let K be the relative velocity of the adjacent anchor chain balls moving towards each other (in the simulation, the spatial vector of the centroid coordinate of each anchor chain ball relative to the global coordinate is calculated in global coordinates, and then the difference is used to calculate the relative velocity), exp is the nonlinear power of the spring, and K is the relative velocity of the adjacent anchor chain balls moving towards each other. 刚度 and C 阻尼 These are the spring stiffness coefficient and damping coefficient, respectively.

[0071] Step 2: Find the shape of the anchor chain and catenary.

[0072] Firstly, the catenary shape of the anchor chain is a non-linear curve, making it difficult to calculate the position of the anchor chain ball after equivalent discretization. To obtain the spatial position of the anchor chain ball, the lengths of the seabed lying section and the underwater suspended section of the anchor chain are estimated based on the mooring radius and water depth. Both the seabed lying section and the underwater suspended section are then simplified into straight line segments for modeling. Figure 5 As shown.

[0073] Based on the anchoring depth D (known), mooring radius R (known), length L of the anchor chain segment lying flat on the seabed (known), and anchor chain ball spacing d... 间距 (Given information) Determine the number of anchor chain balls in the seabed section and the suspended section in the water, respectively. , ,Right now:

[0074] (4);

[0075] (5);

[0076] Define the anchor chain sphere as a sphere. Set the seabed anchoring point as the origin (0,0), then the coordinates of the first mass sphere are (0,0). Based on the relative positions of the nodes, the coordinates of the nth node on the seabed are... The coordinates of the node at the end of the seabed are:

[0077] (6);

[0078] No. Each node is suspended in the water. According to geometric relationships, the position of a suspended node relative to the previous suspended node is:

[0079] (7);

[0080] Then the first The coordinates of the m-th node (the node suspended in the water) are:

[0081] (8);

[0082] Top (the) The coordinates of the nodes (number of nodes) are:

[0083] (9);

[0084] like Figure 6 As shown, since the mooring anchor chain exhibits a catenary shape in a still water environment, the anchor chain set by this method needs to be left still for several seconds during the simulation so that it can return to the catenary shape and the mooring system can reach a balanced state; then, wave, water flow and other working conditions are applied.

[0085] Step 3: Modeling the collision and contact between the anchor chain ball and irregular seabed structures.

[0086] To simulate the collision response characteristics of irregular structures such as seabed reefs and shipwrecks, as well as the uneven seabed surface and anchor chain loads, a three-dimensional model of the uneven seabed surface and irregular structures is constructed based on the geometric dimensions and mass information of the seabed plane and the irregular seabed structures to be modeled.

[0087] like Figure 7 As shown, based on Hertzian contact theory, the contact relationship between the seabed surface, the surface of irregular structures and the anchor chain ball is defined. Multibody-flow dynamics co-simulation is used to simulate the contact and collision between the seabed and irregular structures and the anchor chain ball, and the contact force is calculated.

[0088] Simultaneously, it can create the mechanical properties of seabed reefs and shipwrecks relative to the seabed, and calculate the displacement of irregular seabed structures caused by the impact of anchor chains.

[0089] Step 4: Parametric modeling of anchor chains.

[0090] Based on information such as the anchor point positions at both ends of the anchor chain and the anchoring water depth, a particle fluid dynamics tank is created using the semi-implicit moving particle method. The diameter of the water particles is determined according to the diameter and spacing of the anchor chain spheres. d 水粒子 The particle diameter is less than or equal to the minimum sphere diameter or one-third of the spacing; secondly, based on the water particle movement speed... V 水粒子 And Courant number Courant Determine the step size Δt used for the multibody-flow dynamics co-simulation, and calculate the ratio of the product of the Coulomb number and the water particle diameter to the water particle velocity, where the step size is less than or equal to Δt, as shown in the formula: ;

[0091] The radius r and density of the anchor chain ball Anchorage depth D, mooring radius R, and anchor chain nonlinear spring stiffness K 刚度 Damping coefficient C 阻尼 The length L of the anchor chain lying flat on the seabed and the initial position of each anchor chain ball are set as parameters. At the same time, the collision contact stiffness and damping between the anchor chain and irregular seabed structures are also set as parameters. The spatial coordinates of the anchor chain ball are defined by the above parameter values. At the same time, the ball radius of the anchor chain ball is directly defined in the parent system by means of the parameter value connection function, so as to realize the parameterized modeling of the hydrodynamic load of the anchor chain. Through multibody-flow dynamics joint simulation under gravity, the catenary shape of the anchor chain ball and anchor chain is obtained.

[0092] For example, the analysis condition is that the floating frame of a floating photovoltaic system is subjected to constant current impact, and the dragging of the anchor points of the mooring chain is used to simulate the constant velocity fluid impact condition.

[0093] (1) Simplified mass of the mooring chain system: The mooring system has an anchoring depth of D=6.4m, a mooring radius of R=15.2m, a seabed length of L=10.4m, and a node spacing of d=0.8m. Then, from equations (4) and (5), we have:

[0094] ;

[0095] ;

[0096] The coordinates of the nth mass sphere on the seabed are: The coordinates of the end mass sphere are The 14+m node is suspended in the water, and its coordinates are:

[0097] ;

[0098] The coordinates of the topmost node are .

[0099] The mass of the sphere is m = 170 kg, and its radius is r = 0.25 m.

[0100] (2) Mechanical modeling of mooring anchor chains:

[0101] For tension in a mooring anchor chain, the relative axial force between two adjacent mass spheres is used to simulate it, such as... Figure 8 As shown, the axial force is defined parametrically, and the magnitude of the force is expressed by equation (3);

[0102] For water resistance, this embodiment uses the Translation Force in RecurDyn for parameterization, and the magnitude of the water resistance in the X direction is... ,in, The drag coefficient, This represents the relative velocity of the mass sphere with respect to the global coordinates in the X direction. It is an absolute value function; the damping in the Y and Z directions is similar; in addition, water resistance can also be obtained through rigid body-fluid co-simulation.

[0103] (3) Floating frame modeling: First, build a floating body model and a square trough to hold the liquid.

[0104] (4) Simulation Analysis: RecurDyn-Particleworks co-simulation was used. RecurDyn calculated the forces and motions of the rigid body structure, while Particleworks generated fluid particles and calculated the forces and motions of the particles and the interaction forces between the particles and the rigid body, such as... Figure 9 As shown.

[0105] This embodiment provides a parametric modeling method for anchor chains based on multibody-fluid co-simulation, which has the following technical advantages:

[0106] (1) Solve the problem of low calculation accuracy of traditional potential flow theory models;

[0107] (2) It avoids the direct use of anchor chain links and anchor chain link contact models, which greatly improves computational efficiency;

[0108] (3) The discrete NS equations are solved using meshless particle fluid dynamics, which has higher computational accuracy than traditional potential flow theory. At the same time, particle fluid dynamics has higher computational efficiency than transmission finite element and finite volume methods.

[0109] (4) The equivalent method for anchor chain load and the equivalent order of each parameter are the key points;

[0110] (5) High degree of parameterization and high modeling efficiency: Most of the parameters of the anchor chain have been parameterized, resulting in high modeling efficiency; the parameterization process makes the modeling process easier to carry out through secondary development, which greatly improves the modeling efficiency.

[0111] (6) Strong adaptability: When the mooring system is under different working conditions, such as different water depths, different mooring radii, different floating platforms, or when it is subjected to seabed friction or undercurrents, the parameters of the concentrated mass anchor chain model and the external force parameters are dynamically correlated and adjusted, avoiding remodeling or cumbersome model adjustment.

[0112] (7) Collision simulation between anchor chains and uneven seabed and irregular seabed structures was realized.

[0113] Example 2

[0114] This embodiment provides a parametric modeling system for anchor chains based on multibody-fluid co-simulation, which specifically includes:

[0115] The discrete module is configured to: convert the actual anchor chain into several anchor chain balls to obtain the equivalent anchor chain, obtain the actual anchor chain length, and calculate the anchor chain ball spacing based on the number of anchor chain balls;

[0116] The calculation module is configured to: take a segment of the actual anchor chain, conduct hydrodynamic experiments to obtain the total hydrodynamic force, preliminarily determine the anchor chain ball radius based on the hydrodynamic load consistency requirements and Morrison's equations, and correct the anchor chain ball radius by verifying the consistency of the simulation through hydrodynamic simulation; calculate the density of the anchor chain balls based on the number and radius of the anchor chain balls; obtain the anchoring depth, mooring radius, and length of the seabed horizontal anchor chain segment of the actual anchor chain, and determine the number of anchor chain balls in the seabed horizontal segment and the suspended segment in the water by combining the anchor chain ball spacing, and then determine the position of each anchor chain ball;

[0117] The simulation module is configured to simulate the contact and collision between the anchor chain balls and the seabed and irregular structures and calculate the contact force based on the anchor chain ball radius, anchor chain ball density and the position of each anchor chain ball through multibody-flow dynamics co-simulation.

[0118] Furthermore, the simulation consistency refers to the fact that the hydrodynamic load obtained by multibody-particle fluid dynamics co-simulation of a corresponding equivalent anchor chain in the actual anchor chain is consistent with the total hydrodynamic load obtained by the hydrodynamic experiment.

[0119] Furthermore, the tension characteristics of the anchor chain are expressed using a tensile-resistant but not compressive-resistant equation for adjacent anchor chain balls:

[0120] ;

[0121] in, This represents the actual distance between two adjacent anchor chain balls. K represents the relative speeds of two adjacent anchor chain balls moving towards each other. 刚度 and C 阻尼 These are the spring stiffness coefficient and damping coefficient, d 间距The distance between the anchor chain balls.

[0122] It should be noted that each module in this embodiment corresponds one-to-one with each step in Embodiment 1, and their specific implementation processes are the same, so they will not be repeated here.

[0123] Example 3

[0124] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in the anchor chain parametric modeling method based on multibody-fluid co-simulation as described in Embodiment 1 above.

[0125] Example 4

[0126] This embodiment provides a computer device, such as... Figure 10 As shown, the system includes a display device, an input device, a computer-readable storage medium (volatile memory and non-volatile storage medium), a processor, a communication interface (i.e., a network interface), and a computer program stored on the computer-readable storage medium and executable on the processor. The processor, communication interface, and computer-readable storage medium can be connected via a bus or other means. The communication interface is used to receive and send data, and when the processor executes the program, it implements the steps in the anchor chain parametric modeling method based on multibody-fluid co-simulation described in Embodiment 1 above.

[0127] Any references to memory, storage, database, or other media used in this application and embodiments may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual-rate SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0128] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0129] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0130] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0131] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A parametric modeling method for anchor chains based on multibody-fluid co-simulation, characterized in that, include: Based on multibody dynamics, the actual anchor chain is equivalent to several anchor chain balls, and the spacing between the anchor chain balls is calculated by combining the total length of the actual anchor chain. A particle hydrodynamic tank was created using a semi-implicit moving particle method, and the viscous resistance of the actual anchor chain segment was calculated using constant-speed towing hydrodynamic simulation. Simulations of equivalent anchor chain segments of the same length under the same towing conditions were conducted to calculate the viscous resistance of the equivalent anchor chain segments. The radius of the anchor chain balls was corrected through consistency verification. The density of the anchor chain balls was calculated based on the number and radius of the anchor chain balls. The anchoring depth, mooring radius, and length of the seabed flat anchor chain segment of the actual anchor chain were obtained. Combined with the spacing of the anchor chain balls, the number of anchor chain balls in the seabed flat segment and the suspended segment in the water was determined, and then the initial position of each anchor chain ball was determined. Models of the seabed and its irregular structures are created, and multibody-flow dynamics joint simulations are performed under gravity by combining the radius, density, and initial position of each anchor chain ball.

2. The parametric modeling method for anchor chains based on multibody-fluid co-simulation as described in claim 1, characterized in that, The number of anchor chain balls in the seabed horizontal section and the underwater suspended section are respectively: ; ;in, This refers to the number of anchor chain balls on the horizontal section of the seabed. Where d is the number of anchor chain balls suspended in the water, D is the anchoring depth, R is the mooring radius, L is the length of the anchor chain segment lying flat on the seabed, and d is the anchor chain ball length suspended in the water. 间距 The distance between the anchor chain balls.

3. The parametric modeling method for anchor chains based on multibody-fluid co-simulation as described in claim 1, characterized in that, The tension characteristics of the anchor chain are expressed using the tensile-resistant but not compressive-resistant equation for adjacent anchor chain balls: ； in, This represents the actual distance between two adjacent anchor chain balls. K represents the relative speeds of two adjacent anchor chain balls moving towards each other. 刚度 and C 阻尼 These are the spring stiffness coefficient and damping coefficient, d 间距 The distance between the anchor chain balls.

4. The parametric modeling method for anchor chains based on multibody-fluid co-simulation as described in claim 1, characterized in that, Based on Hertzian contact theory, the contact relationship between the seabed surface, the surface of irregular structures, and the anchor chain ball is defined.

5. The parametric modeling method for anchor chains based on multibody-fluid co-simulation as described in claim 1, characterized in that, Also includes: Based on the anchor point positions at both ends of the anchor chain and the anchoring water depth, a particle fluid dynamics water tank is created using the moving particle semi-implicit method. The diameter of the water particles and the calculation step size are determined by combining the diameter and spacing of the anchor chain balls.

6. A parametric modeling system for anchor chains based on multibody-fluid co-simulation, characterized in that, include: The discrete module is configured to: based on multibody dynamics, the actual anchor chain is equivalent to several anchor chain balls, and the spacing between the anchor chain balls is calculated in combination with the total length of the actual anchor chain; The calculation module is configured to: create a particle hydrodynamic tank using a semi-implicit moving particle method and calculate the viscous resistance of the actual anchor chain segment using constant-speed towing hydrodynamic simulation; perform simulations under the same towing conditions on equivalent anchor chain segments of the same length and calculate the viscous resistance of the equivalent anchor chain segments; correct the anchor chain ball radius through consistency verification; calculate the anchor chain ball density based on the number and radius of the anchor chain balls; obtain the anchoring depth, mooring radius, and length of the seabed flat anchor chain segment of the actual anchor chain, and determine the number of anchor chain balls in the seabed flat segment and the underwater suspended segment in combination with the anchor chain ball spacing, and then determine the initial position of each anchor chain ball; The simulation module is configured to create a model of the seabed and its irregular structures, and perform a multibody-flow dynamics co-simulation under gravity by combining the radius, density and initial position of each anchor chain ball.

7. The parametric modeling system for anchor chains based on multibody-fluid co-simulation as described in claim 6, characterized in that, The number of anchor chain balls in the seabed horizontal section and the underwater suspended section are respectively: ; ;in, This refers to the number of anchor chain balls on the horizontal section of the seabed. Where d is the number of anchor chain balls suspended in the water, D is the anchoring depth, R is the mooring radius, L is the length of the anchor chain segment lying flat on the seabed, and d is the anchor chain ball length suspended in the water. 间距 The distance between the anchor chain balls.

8. The parametric modeling system for anchor chains based on multibody-fluid co-simulation as described in claim 6, characterized in that, The tension characteristics of the anchor chain are expressed using the tensile-resistant but not compressive-resistant equation for adjacent anchor chain balls: ； in, This represents the actual distance between two adjacent anchor chain balls. K represents the relative speeds of two adjacent anchor chain balls moving towards each other. 刚度 and C 阻尼 These are the spring stiffness coefficient and damping coefficient, d 间距 The distance between the anchor chain balls.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the parametric modeling method for anchor chains based on multibody-fluid co-simulation as described in any one of claims 1-5.

10. A computer device comprising a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the anchor chain parametric modeling method based on multibody-fluid co-simulation as described in any one of claims 1-5.

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